This document discusses a methodology for simulating cementitious materials using the discrete element method (DEM) to study the effects of cement blending on pore network characteristics and transport-based durability. The methodology involves simulating particle packing and hydration using DEM and modeling techniques. Pore networks are then analyzed using algorithms to characterize topology and geometry. Parameters from these analyses can be input into models to estimate permeability and durability. The methodology is applied to study gap-graded rice husk ash blends with cement to determine the impact of particle size distribution gaps on pore characteristics relevant to durability.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Three dimensional finite element modeling of pervious concrete pavementeSAT Journals
Abstract Pervious concrete has the unique characteristic of allowing water to pass through its porous matrix. . Pervious concrete pavement systems usually have three main layers, pervious concrete on the top, a subbase layer of aggregate for water storage in the middle and the subgrade (soil) layer below. Finite element modeling of this novel material is challenging due to its complex porous characteristics. In this paper, a method has been proposed to model pervious concrete pavement using finite element methods, which includes a modified approach to capture the unique vertical porosity distribution in the pervious concrete layer by averaging the distribution in three distinct vertical sections. The mechanical properties of the pervious concrete layer are assumed to vary along its depth since the porosity of the pervious concrete also varies with depth. ABAQUS, a general-purpose finite element software package was used to develop the model and perform the analysis. The model was validated through a convergence study, and in comparison with the analytical theory of tensile stress and deflection for traditional concrete pavement. In addition, the significance of the porosity distribution model was validated by comparing the results from EverFE – a specific software for pavement structure analysis. It was found that there is significant difference in tensile stress if modeled using the modified vertical porosity distribution in the previous concrete layer to more fully capture its vertical porosity distribution, as compared to an averaged porosity model in the previous concrete layer. It was also noted that compressive stress demand may have increased importance for pervious concrete, but only for highly porous applications which are not commonly used. Keywords: pervious concrete, vertical porosity, finite element, critical loading, stress, deflection
Moisture penetration causes many direct and indirect distresses in flexible asphalt pavement. Due to damage in asphalt concrete and binder by moisture are the prime concern of failure for flexible pavement worldwide. The causes and prediction are investigated in this study. The asphalt binder was modified with carbon nanotubes (CNT) with very small percentages. The modified binder was simulated with moisture damage with AASHTO T-283 methods. In this study, polymer and carbon nanotubes (CNT) have been added to liquid asphalt binder to examine whether the resulting modified binder has improved moisture damage resistance. Using laboratory tested data, an artificial intelligence modeling technique has been utilized to determine the moisture damage behavior of the modified binder. Multi-Layer Perceptron (MLP) provides the best prediction for wet and dry samples AFM readings with R2 values respectively 0.6407 and 0.8371.
Today, retrofitting of the old structures is important. For this purpose, determination of capacities for these buildings, which mostly are non-ductile, is a very useful tool. In this context, non-ductile RC joint in concrete structures, as one of the most important elements in these buildings are considered, and the shear capacity, especially for retrofitting goals can be very beneficial. In this paper, three famous soft computing methods including artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS) and also group method of data handling (GMDH) were used to estimating the shear capacity for this type of RC joints. A set of experimental data which were a failure in joint are collected, and first, the effective parameters were identified. Based on these parameters, predictive models are presented in detail and compare with each other. The results showed that the considered soft computing techniques are very good capabilities to determine the shear capacity.
This document discusses a study that investigated the fracture behavior of pervious concrete specimens with varying pore structures and fiber contents. The researchers tested notched beams in three-point bending to characterize fracture toughness and critical crack tip opening displacement. They used stereological and morphological methods to analyze the pore structures of the concrete mixtures from images. The results showed that fracture toughness depended primarily on porosity, and higher porosity or larger pore sizes reduced toughness. Fibers had a greater effect on post-peak response in mixtures with higher porosity. Pore spacing and tortuosity helped explain these effects. A statistical model and sensitivity analysis quantified the influence of pore structure features and fiber content on fracture toughness.
A coupled SPH-DEM model for fluid-structure interaction problems with free-su...Ke Wu
1. The document presents a coupled Smoothed Particle Hydrodynamics (SPH)-Discrete Element Method (DEM) model for simulating fluid-structure interaction problems involving free-surface fluid flow and structural failure.
2. SPH is used to model the fluid domain based on the Navier-Stokes equations, while DEM with a parallel bond model is used to represent the solid structure as a hexagonal packing of bonded particles.
3. Validation tests show good agreement with analytical and published results for DEM fracture modeling, SPH fluid modeling, and coupled SPH-DEM modeling without fracture. Simulation results indicate the model can capture the full fluid-structure interaction process from structural deformation to failure and post-failure movement.
This document presents a study that uses gene expression programming (GEP) to develop a model for predicting sediment transport in sewers under no-deposition conditions. The study first reviews existing sediment transport equations developed using dimensional analysis and semi-experimental methods. It then describes using GEP to present six different models considering effective parameters on sediment transport. The best model is selected by comparing their performance on validation data not used in model development. The results show the GEP model achieves a root mean squared error of 0.12 and mean average percentage error of 2.56 on the training data, and 0.14 and 2.82 respectively on the validation data. This performance is compared to existing sediment transport equations.
To Experimental Study of Comparison and Development of Design for Rigid Pavem...Agriculture Journal IJOEAR
Abstract— The development of design have been discussed adopted various types methods use. The Hadi and Arfiadi Method presents a formulation for the optimum rigid road pavement design by genetic algorithm, a new method. The Westergaard’s Method determines the stresses in the rigid concrete slab and also the pressure-deformation curve which depend upon the relative stiffness of the slab and the subgrade. Razouki and Al-Muhana also developed stress charts similar to Westergaard’s method. The paper reveals that the effects on the maximum bending tensile stress are quite significant due to the modulus of subgrade reaction, modulus of elasticity of concrete and slab The Maharaj and Gill method have performed axisymmetric finite element analysis by varying parameters, the thickness of pavement, pressure and elastic modulus of subgrade. The advantage of this method is that four types of design charts have been presented which other methods have note done. First type of design chart has been plotted between thickness of pavement and nodal deflections for various pressures for a particular elastic modulus of soil. Second type of design chart has been plotted between thickness of pavement and element stress for various pressures for a particular elastic modulus of soil. The third type of design chart has been plotted between thickness of pavement and nodal deflections for various elastic moduli of subgrade for a particular pressure. Each of the design charts has three parameters. For two known parameters, the third parameter can be obtained.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Three dimensional finite element modeling of pervious concrete pavementeSAT Journals
Abstract Pervious concrete has the unique characteristic of allowing water to pass through its porous matrix. . Pervious concrete pavement systems usually have three main layers, pervious concrete on the top, a subbase layer of aggregate for water storage in the middle and the subgrade (soil) layer below. Finite element modeling of this novel material is challenging due to its complex porous characteristics. In this paper, a method has been proposed to model pervious concrete pavement using finite element methods, which includes a modified approach to capture the unique vertical porosity distribution in the pervious concrete layer by averaging the distribution in three distinct vertical sections. The mechanical properties of the pervious concrete layer are assumed to vary along its depth since the porosity of the pervious concrete also varies with depth. ABAQUS, a general-purpose finite element software package was used to develop the model and perform the analysis. The model was validated through a convergence study, and in comparison with the analytical theory of tensile stress and deflection for traditional concrete pavement. In addition, the significance of the porosity distribution model was validated by comparing the results from EverFE – a specific software for pavement structure analysis. It was found that there is significant difference in tensile stress if modeled using the modified vertical porosity distribution in the previous concrete layer to more fully capture its vertical porosity distribution, as compared to an averaged porosity model in the previous concrete layer. It was also noted that compressive stress demand may have increased importance for pervious concrete, but only for highly porous applications which are not commonly used. Keywords: pervious concrete, vertical porosity, finite element, critical loading, stress, deflection
Moisture penetration causes many direct and indirect distresses in flexible asphalt pavement. Due to damage in asphalt concrete and binder by moisture are the prime concern of failure for flexible pavement worldwide. The causes and prediction are investigated in this study. The asphalt binder was modified with carbon nanotubes (CNT) with very small percentages. The modified binder was simulated with moisture damage with AASHTO T-283 methods. In this study, polymer and carbon nanotubes (CNT) have been added to liquid asphalt binder to examine whether the resulting modified binder has improved moisture damage resistance. Using laboratory tested data, an artificial intelligence modeling technique has been utilized to determine the moisture damage behavior of the modified binder. Multi-Layer Perceptron (MLP) provides the best prediction for wet and dry samples AFM readings with R2 values respectively 0.6407 and 0.8371.
Today, retrofitting of the old structures is important. For this purpose, determination of capacities for these buildings, which mostly are non-ductile, is a very useful tool. In this context, non-ductile RC joint in concrete structures, as one of the most important elements in these buildings are considered, and the shear capacity, especially for retrofitting goals can be very beneficial. In this paper, three famous soft computing methods including artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS) and also group method of data handling (GMDH) were used to estimating the shear capacity for this type of RC joints. A set of experimental data which were a failure in joint are collected, and first, the effective parameters were identified. Based on these parameters, predictive models are presented in detail and compare with each other. The results showed that the considered soft computing techniques are very good capabilities to determine the shear capacity.
This document discusses a study that investigated the fracture behavior of pervious concrete specimens with varying pore structures and fiber contents. The researchers tested notched beams in three-point bending to characterize fracture toughness and critical crack tip opening displacement. They used stereological and morphological methods to analyze the pore structures of the concrete mixtures from images. The results showed that fracture toughness depended primarily on porosity, and higher porosity or larger pore sizes reduced toughness. Fibers had a greater effect on post-peak response in mixtures with higher porosity. Pore spacing and tortuosity helped explain these effects. A statistical model and sensitivity analysis quantified the influence of pore structure features and fiber content on fracture toughness.
A coupled SPH-DEM model for fluid-structure interaction problems with free-su...Ke Wu
1. The document presents a coupled Smoothed Particle Hydrodynamics (SPH)-Discrete Element Method (DEM) model for simulating fluid-structure interaction problems involving free-surface fluid flow and structural failure.
2. SPH is used to model the fluid domain based on the Navier-Stokes equations, while DEM with a parallel bond model is used to represent the solid structure as a hexagonal packing of bonded particles.
3. Validation tests show good agreement with analytical and published results for DEM fracture modeling, SPH fluid modeling, and coupled SPH-DEM modeling without fracture. Simulation results indicate the model can capture the full fluid-structure interaction process from structural deformation to failure and post-failure movement.
This document presents a study that uses gene expression programming (GEP) to develop a model for predicting sediment transport in sewers under no-deposition conditions. The study first reviews existing sediment transport equations developed using dimensional analysis and semi-experimental methods. It then describes using GEP to present six different models considering effective parameters on sediment transport. The best model is selected by comparing their performance on validation data not used in model development. The results show the GEP model achieves a root mean squared error of 0.12 and mean average percentage error of 2.56 on the training data, and 0.14 and 2.82 respectively on the validation data. This performance is compared to existing sediment transport equations.
To Experimental Study of Comparison and Development of Design for Rigid Pavem...Agriculture Journal IJOEAR
Abstract— The development of design have been discussed adopted various types methods use. The Hadi and Arfiadi Method presents a formulation for the optimum rigid road pavement design by genetic algorithm, a new method. The Westergaard’s Method determines the stresses in the rigid concrete slab and also the pressure-deformation curve which depend upon the relative stiffness of the slab and the subgrade. Razouki and Al-Muhana also developed stress charts similar to Westergaard’s method. The paper reveals that the effects on the maximum bending tensile stress are quite significant due to the modulus of subgrade reaction, modulus of elasticity of concrete and slab The Maharaj and Gill method have performed axisymmetric finite element analysis by varying parameters, the thickness of pavement, pressure and elastic modulus of subgrade. The advantage of this method is that four types of design charts have been presented which other methods have note done. First type of design chart has been plotted between thickness of pavement and nodal deflections for various pressures for a particular elastic modulus of soil. Second type of design chart has been plotted between thickness of pavement and element stress for various pressures for a particular elastic modulus of soil. The third type of design chart has been plotted between thickness of pavement and nodal deflections for various elastic moduli of subgrade for a particular pressure. Each of the design charts has three parameters. For two known parameters, the third parameter can be obtained.
Efficiency of vertical drains using finite element method may 2017Dr Mazin Alhamrany
Incorporating one-dimensional bar elements with two-dimensional quadrilateral axisymmetrical elements to tackle problems of consolidation of clay with vertical drains.
Rupture Probability of Type of Coarse Aggregate on Fracture Surface of Concrete IRJET Journal
This document discusses a study on the rupture probability of coarse aggregates on the fracture surface of concrete. Different types of aggregates including granite, dolerite, quartzite, limestone, dolomitic limestone and river gravel were used to produce concrete with target compressive strengths of 30, 50 and 70 MPa.
The results showed that limestone concrete exhibited the highest rupture probability of coarse aggregate (RPCA) values, followed by granite and dolomitic limestone concrete, while river gravel concrete had the lowest values. Within the same grade of concrete, variations in aggregate type led to differences in RPCA even when compressive strength was similar. The mineral composition, texture and proportions within the aggregates influenced the bond strength
This document discusses a finite element analysis that was performed to evaluate the responses of asphalt pavement mixtures modified with different additives. A 2D model was created using PLAXIS software to simulate pavement structures consisting of an asphalt layer modified with nano silica, silica fume, lime, rubber or polymer over an aggregate base and subgrade. Laboratory testing was conducted to determine modulus and Poisson's ratio of the modified mixtures. The model analyzed vertical displacement and stresses under traffic loads and found that mixtures modified with silica fume exhibited the least deformation and stresses.
Numerical Modelling of Soil Improvement Using Geo-fabricsIJERA Editor
A series of finite element (FE) simulations are carried out to evaluate the benefits of integrating a high modulus
geo-fabric as reinforcement into the soil-layers in this paper. Finite element analysis can handle complex
geometry, different boundary conditions and material properties with ease. In the present study a finite element
program, PLAXIS, which has proved its efficacy in geotechnical application, is used. This paper presents a two
dimensional plain strain finite element model that analysis of foundation in unreinforced and geo-fabric
reinforced soil subjected to distributed load condition.
This review article summarizes research on factors that control skid resistance at the tire-pavement interface. It discusses key parameters such as surface texture, tire tread, temperature, and loading conditions. Pavement macrotexture, characterized by mean texture depth, is identified as the most important factor for skid resistance. Microtexture and factors that reduce surface asperities like traffic polishing also significantly impact skid resistance over time. The article provides an overview of different methods to measure skid resistance and texture in both laboratory and field settings.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IRJET- Use of Ferrochrome Slag as Aggregate in Concrete- A ReviewIRJET Journal
The document reviews the use of ferrochrome slag as an aggregate in concrete. Ferrochrome slag is a solid waste produced during ferrochrome alloy steel production. It has physical and chemical properties suitable for use as a concrete aggregate. Studies have shown that water cooled ferrochrome slag can replace up to 30% of natural sand in concrete with only minor reductions in compressive strength, workability, and other properties. The concrete maintains sufficient strength for general construction uses even with a 30% replacement of sand by the industrial waste slag aggregate. Using waste ferrochrome slag in concrete has benefits for waste management and reduces demand for natural resources.
Influence of Construction Parameters on Performance of Dense Graded Bituminou...IOSR Journals
This document discusses a study that investigated the influence of construction parameters on the properties and performance of dense graded bituminous mixes. Specifically, it varied bitumen content, air void content, and compaction effort to determine their effects on Marshall stability, indirect tensile strength, and predicted fatigue and rutting performance based on mechanistic-empirical pavement design modeling. The study found that bitumen content, air voids, and density significantly impacted mix properties like indirect tensile strength as well as predicted pavement distress. Maintaining optimal bitumen content and air voids through quality control was shown to improve predicted pavement performance.
Mathematical Relationships between the Compressive Strength and Some Other St...IOSR Journals
This document establishes mathematical relationships between the compressive strength and other properties (water absorption, flexural strength, and split tensile strength) of sand-quarry dust blocks through regression analysis. Tests were conducted on blocks with varying mix ratios of cement, sand, and quarry dust. Linear and quadratic models relating each additional property to compressive strength were developed. The models were found to have low standard error and high coefficient of determination, indicating they adequately predict relationships between compressive strength and other block properties. The relationships can be used when only compressive strength testing is conducted to estimate additional properties.
Applications of FEM in Geotechnical Engineering / State-of-the-ArtDr Mazin Alhamrany
This presentation supposed to be given during the 1st Iraqi International Conference on Geotechnical Engineering (ICGE) - Baghdad - 17-19 February 2020. I am uploading this document on LinkedIn as a contribution providing geotechnical engineers an insight for the earlier, recent and "potential" future applications of FEM in the field of Geotechnical Engineering. With my best wishes to the Iraqi Geotechnical Society.
The effect of aggregate density on pavement performance of SMA-13 asphalt mix...IJERA Editor
This paper chooses the top layer SMA-13 asphalt mixture material as the research object. Basalt was selected as
pavement material, and modified SBS asphalt was used as a cementing material. Two basalt aggregates with
different densities were used to carry out standard Marshall test in the laboratory.Aimed at the volume
parameters of the asphalt mixture carry on anaiysis,and obtian the effect of aggregate density on pavement
performance of SMA-13 asphalt mixture, which is that the density of aggregate has a significant effect on the
void ratio, saturation, and the gap rate of the aggregate, thus affecting the pavement performance of the asphalt
mixture
This document presents the results of a parametric study to optimize the design of post-tensioned concrete box-girder pedestrian bridges with main spans ranging from 30 to 60 meters. An optimization algorithm called SAMO2 was used to minimize the cost by varying 33 design variables related to geometry, materials, and construction. The optimal solutions showed that depth and number of prestressing strands correlated with main span length, while slab thicknesses generally took minimum allowed values. Increasing the main span by 1 meter on average increased total cost by 6.38 euros per square meter. Concrete strength varied between 35 to 55 MPa but tended to increase with longer spans.
rutting performance evaluation of polymer modified binder in HMA mix design Nur Zulkifli
The document provides background information on a study evaluating the rutting performance of hot mix asphalt (HMA) using polymer modified binders. It discusses factors that contribute to rutting in flexible pavements like excessive traffic loads and inadequate mixture stability. The objectives of the study are to determine and compare the rutting performance of HMA mixtures using unmodified and polymer modified binders. The scope will focus on evaluating rutting performance through the Asphalt Pavement Analyzer using three binder types (unmodified and two polymer modified) based on the Superpave mix design method.
This document discusses unstructured grid generation for reservoir modeling and simulation that considers reservoir properties. It presents two approaches for designing unstructured grids for flow simulators using tetrahedral grids. One technique directly uses reservoir properties to define grid element volumes, while the other uses flow-based gridding with a permeability model. The research aims to develop grid generation methods that integrate geological and flow modeling requirements. It also outlines a modified reservoir modeling workflow where grid design considers both modeling heterogeneity and flow simulation needs simultaneously.
An Investigation of the Interlayer Adhesion Strength in Deeper Layers of the ...AM Publications
A road pavement structure is typically composed of different layers arranged one on top of the other, all supported by a natural or improved subgrade. The main purpose of this configuration is to provide the most effective structure with adequate potential to spread traffic loading from the surface to the subgrade with minimum damage. In spite of material properties and construction techniques, researchers have shown that the overall pavement performance is significantly influenced by the interlayer adhesion condition throughout the pavement structure ([8], [11], [21], [22]). Lack of intimate contact between layers results in them acting as individuals rather than as a thick bonded unit. This therefore induces overloading of layers which leads to premature deterioration of the entire structure due to traffic induced distresses. This work, therefore investigated the interlayer adhesion characteristics between the granular base and the lightly cemented subbase of a typical South African pavement structure. The influence of bonding condition on the overall pavement performance was also studied. A series of interlayer direct shear tests was run on 300 x 300 mm samples made of two layers: a 100mm G2 Granular Base (GB) compacted on top of the 100mm Cement Treated Subbase (CTSB) composed of a G5 material stabilised with 1.8% of cement. Effects of the CTSB scarification, normal pressure and moisture conditions were analysed whereby the results of the interlayer strength tests were compared with those of intra-layer strength tests. The comparative analysis showed that scarifying the CTSB before laying the GB enhances intimate contact between two layers and stimulates the unison interaction which, according to structural modelling results, improves the overall pavement performance.
IRJET- Mix Design for Wearing Course of Flexible Road Pavement by Marshal...IRJET Journal
This document presents a mix design for the wearing course of a flexible road pavement using the Marshall method. Laboratory tests were conducted on aggregates, asphalt, and pavement mixtures. The results showed the aggregates met specifications and had properties suitable for use in a wearing course. The optimum asphalt content was determined to be 5.0% based on a variety of mix parameters measured at different asphalt contents, including density, air voids, voids in the mineral aggregate, voids filled with asphalt, stability, and flow. All mix parameters at the 5.0% asphalt content met the required specifications.
HVOF Sprayed WC-Cocr Coating on Mild Steel: Microstructure and Wear Evaluationiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IRJET- Evaluating the Compactness of Boardcrete Blocks using PUNDIT ApparatusIRJET Journal
This study evaluated the compactness of three types of boardcrete blocks (A, B, C) containing different ratios of cardboard and cement using an ultrasonic pulse velocity (UPV) technique. Specimens were tested using a PUNDIT apparatus, which transmits and receives ultrasonic pulses to measure velocity. The results showed that block A with a 1:1:1.5 cement:cardboard:sand ratio had the highest UPV of 2.02 km/sec, while block C with a 1:2:4 ratio had the lowest velocity of 0.59 km/sec, indicating lower compactness. In general, increasing cardboard content decreased the UPV, suggesting boardcrete could provide lightweight and soundproof
Behaviour of pavement quality concrete with reclaimed asphalt pavement aggreg...eSAT Journals
This document summarizes a study on the use of reclaimed asphalt pavement (RAP) aggregates in pavement quality concrete. The study investigated how replacing natural aggregates with RAP aggregates at different percentages (100%, 75%, 50%, 25%) impacted the strength and durability properties of the concrete. Specimens were tested to determine compressive strength, flexural strength, workability and fatigue resistance. Test results showed that mixes with 25% RAP replacement achieved strength properties closest to normal concrete. A mix with 75% natural aggregate and 25% RAP aggregate was identified as a feasible option for use in concrete pavements based on its strength performance.
Combustion refers to the rapid oxidation of fuel accompanied by heat or heat and light. Complete combustion requires an adequate oxygen supply. The objective of good combustion is to release all the heat from fuel by controlling temperature, turbulence for mixing fuel and oxygen, and reaction time. Stoichiometry calculates the theoretical air required for combustion and can determine excess air by measuring flue gas CO2 levels. A certain amount of excess air is needed for complete combustion but too much leads to heat losses.
The document defines combustion as a chemical process where a substance reacts with oxygen in air to produce heat and light. There are several types of combustion described, including spontaneous, rapid, complete, and incomplete combustion as well as explosions. Rapid combustion occurs when a substance burns quickly, producing heat and flame, often with the introduction of external heat. Incomplete combustion results in only partial burning of a fuel due to a lack of oxygen or low temperature, producing carbon monoxide. For combustion to occur, there must be a combustible substance, a supply of oxygen (air), and enough heat to raise the substance to its ignition temperature.
Petroleum coke is a byproduct of the oil refining process with a high calorific value and lower cost than coal. It can be used in cement production, with limitations on the amount used due to its high sulfur content. Using petcoke up to 24% as a substitute for existing fuel in a cement plant can maintain acceptable sulfur ratios and volatile matter levels in the clinker and coal mix, while lowering fuel costs. However, its abrasive nature and difficulty burning require modifications to equipment for effective utilization in kilns and calciners.
Efficiency of vertical drains using finite element method may 2017Dr Mazin Alhamrany
Incorporating one-dimensional bar elements with two-dimensional quadrilateral axisymmetrical elements to tackle problems of consolidation of clay with vertical drains.
Rupture Probability of Type of Coarse Aggregate on Fracture Surface of Concrete IRJET Journal
This document discusses a study on the rupture probability of coarse aggregates on the fracture surface of concrete. Different types of aggregates including granite, dolerite, quartzite, limestone, dolomitic limestone and river gravel were used to produce concrete with target compressive strengths of 30, 50 and 70 MPa.
The results showed that limestone concrete exhibited the highest rupture probability of coarse aggregate (RPCA) values, followed by granite and dolomitic limestone concrete, while river gravel concrete had the lowest values. Within the same grade of concrete, variations in aggregate type led to differences in RPCA even when compressive strength was similar. The mineral composition, texture and proportions within the aggregates influenced the bond strength
This document discusses a finite element analysis that was performed to evaluate the responses of asphalt pavement mixtures modified with different additives. A 2D model was created using PLAXIS software to simulate pavement structures consisting of an asphalt layer modified with nano silica, silica fume, lime, rubber or polymer over an aggregate base and subgrade. Laboratory testing was conducted to determine modulus and Poisson's ratio of the modified mixtures. The model analyzed vertical displacement and stresses under traffic loads and found that mixtures modified with silica fume exhibited the least deformation and stresses.
Numerical Modelling of Soil Improvement Using Geo-fabricsIJERA Editor
A series of finite element (FE) simulations are carried out to evaluate the benefits of integrating a high modulus
geo-fabric as reinforcement into the soil-layers in this paper. Finite element analysis can handle complex
geometry, different boundary conditions and material properties with ease. In the present study a finite element
program, PLAXIS, which has proved its efficacy in geotechnical application, is used. This paper presents a two
dimensional plain strain finite element model that analysis of foundation in unreinforced and geo-fabric
reinforced soil subjected to distributed load condition.
This review article summarizes research on factors that control skid resistance at the tire-pavement interface. It discusses key parameters such as surface texture, tire tread, temperature, and loading conditions. Pavement macrotexture, characterized by mean texture depth, is identified as the most important factor for skid resistance. Microtexture and factors that reduce surface asperities like traffic polishing also significantly impact skid resistance over time. The article provides an overview of different methods to measure skid resistance and texture in both laboratory and field settings.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IRJET- Use of Ferrochrome Slag as Aggregate in Concrete- A ReviewIRJET Journal
The document reviews the use of ferrochrome slag as an aggregate in concrete. Ferrochrome slag is a solid waste produced during ferrochrome alloy steel production. It has physical and chemical properties suitable for use as a concrete aggregate. Studies have shown that water cooled ferrochrome slag can replace up to 30% of natural sand in concrete with only minor reductions in compressive strength, workability, and other properties. The concrete maintains sufficient strength for general construction uses even with a 30% replacement of sand by the industrial waste slag aggregate. Using waste ferrochrome slag in concrete has benefits for waste management and reduces demand for natural resources.
Influence of Construction Parameters on Performance of Dense Graded Bituminou...IOSR Journals
This document discusses a study that investigated the influence of construction parameters on the properties and performance of dense graded bituminous mixes. Specifically, it varied bitumen content, air void content, and compaction effort to determine their effects on Marshall stability, indirect tensile strength, and predicted fatigue and rutting performance based on mechanistic-empirical pavement design modeling. The study found that bitumen content, air voids, and density significantly impacted mix properties like indirect tensile strength as well as predicted pavement distress. Maintaining optimal bitumen content and air voids through quality control was shown to improve predicted pavement performance.
Mathematical Relationships between the Compressive Strength and Some Other St...IOSR Journals
This document establishes mathematical relationships between the compressive strength and other properties (water absorption, flexural strength, and split tensile strength) of sand-quarry dust blocks through regression analysis. Tests were conducted on blocks with varying mix ratios of cement, sand, and quarry dust. Linear and quadratic models relating each additional property to compressive strength were developed. The models were found to have low standard error and high coefficient of determination, indicating they adequately predict relationships between compressive strength and other block properties. The relationships can be used when only compressive strength testing is conducted to estimate additional properties.
Applications of FEM in Geotechnical Engineering / State-of-the-ArtDr Mazin Alhamrany
This presentation supposed to be given during the 1st Iraqi International Conference on Geotechnical Engineering (ICGE) - Baghdad - 17-19 February 2020. I am uploading this document on LinkedIn as a contribution providing geotechnical engineers an insight for the earlier, recent and "potential" future applications of FEM in the field of Geotechnical Engineering. With my best wishes to the Iraqi Geotechnical Society.
The effect of aggregate density on pavement performance of SMA-13 asphalt mix...IJERA Editor
This paper chooses the top layer SMA-13 asphalt mixture material as the research object. Basalt was selected as
pavement material, and modified SBS asphalt was used as a cementing material. Two basalt aggregates with
different densities were used to carry out standard Marshall test in the laboratory.Aimed at the volume
parameters of the asphalt mixture carry on anaiysis,and obtian the effect of aggregate density on pavement
performance of SMA-13 asphalt mixture, which is that the density of aggregate has a significant effect on the
void ratio, saturation, and the gap rate of the aggregate, thus affecting the pavement performance of the asphalt
mixture
This document presents the results of a parametric study to optimize the design of post-tensioned concrete box-girder pedestrian bridges with main spans ranging from 30 to 60 meters. An optimization algorithm called SAMO2 was used to minimize the cost by varying 33 design variables related to geometry, materials, and construction. The optimal solutions showed that depth and number of prestressing strands correlated with main span length, while slab thicknesses generally took minimum allowed values. Increasing the main span by 1 meter on average increased total cost by 6.38 euros per square meter. Concrete strength varied between 35 to 55 MPa but tended to increase with longer spans.
rutting performance evaluation of polymer modified binder in HMA mix design Nur Zulkifli
The document provides background information on a study evaluating the rutting performance of hot mix asphalt (HMA) using polymer modified binders. It discusses factors that contribute to rutting in flexible pavements like excessive traffic loads and inadequate mixture stability. The objectives of the study are to determine and compare the rutting performance of HMA mixtures using unmodified and polymer modified binders. The scope will focus on evaluating rutting performance through the Asphalt Pavement Analyzer using three binder types (unmodified and two polymer modified) based on the Superpave mix design method.
This document discusses unstructured grid generation for reservoir modeling and simulation that considers reservoir properties. It presents two approaches for designing unstructured grids for flow simulators using tetrahedral grids. One technique directly uses reservoir properties to define grid element volumes, while the other uses flow-based gridding with a permeability model. The research aims to develop grid generation methods that integrate geological and flow modeling requirements. It also outlines a modified reservoir modeling workflow where grid design considers both modeling heterogeneity and flow simulation needs simultaneously.
An Investigation of the Interlayer Adhesion Strength in Deeper Layers of the ...AM Publications
A road pavement structure is typically composed of different layers arranged one on top of the other, all supported by a natural or improved subgrade. The main purpose of this configuration is to provide the most effective structure with adequate potential to spread traffic loading from the surface to the subgrade with minimum damage. In spite of material properties and construction techniques, researchers have shown that the overall pavement performance is significantly influenced by the interlayer adhesion condition throughout the pavement structure ([8], [11], [21], [22]). Lack of intimate contact between layers results in them acting as individuals rather than as a thick bonded unit. This therefore induces overloading of layers which leads to premature deterioration of the entire structure due to traffic induced distresses. This work, therefore investigated the interlayer adhesion characteristics between the granular base and the lightly cemented subbase of a typical South African pavement structure. The influence of bonding condition on the overall pavement performance was also studied. A series of interlayer direct shear tests was run on 300 x 300 mm samples made of two layers: a 100mm G2 Granular Base (GB) compacted on top of the 100mm Cement Treated Subbase (CTSB) composed of a G5 material stabilised with 1.8% of cement. Effects of the CTSB scarification, normal pressure and moisture conditions were analysed whereby the results of the interlayer strength tests were compared with those of intra-layer strength tests. The comparative analysis showed that scarifying the CTSB before laying the GB enhances intimate contact between two layers and stimulates the unison interaction which, according to structural modelling results, improves the overall pavement performance.
IRJET- Mix Design for Wearing Course of Flexible Road Pavement by Marshal...IRJET Journal
This document presents a mix design for the wearing course of a flexible road pavement using the Marshall method. Laboratory tests were conducted on aggregates, asphalt, and pavement mixtures. The results showed the aggregates met specifications and had properties suitable for use in a wearing course. The optimum asphalt content was determined to be 5.0% based on a variety of mix parameters measured at different asphalt contents, including density, air voids, voids in the mineral aggregate, voids filled with asphalt, stability, and flow. All mix parameters at the 5.0% asphalt content met the required specifications.
HVOF Sprayed WC-Cocr Coating on Mild Steel: Microstructure and Wear Evaluationiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IRJET- Evaluating the Compactness of Boardcrete Blocks using PUNDIT ApparatusIRJET Journal
This study evaluated the compactness of three types of boardcrete blocks (A, B, C) containing different ratios of cardboard and cement using an ultrasonic pulse velocity (UPV) technique. Specimens were tested using a PUNDIT apparatus, which transmits and receives ultrasonic pulses to measure velocity. The results showed that block A with a 1:1:1.5 cement:cardboard:sand ratio had the highest UPV of 2.02 km/sec, while block C with a 1:2:4 ratio had the lowest velocity of 0.59 km/sec, indicating lower compactness. In general, increasing cardboard content decreased the UPV, suggesting boardcrete could provide lightweight and soundproof
Behaviour of pavement quality concrete with reclaimed asphalt pavement aggreg...eSAT Journals
This document summarizes a study on the use of reclaimed asphalt pavement (RAP) aggregates in pavement quality concrete. The study investigated how replacing natural aggregates with RAP aggregates at different percentages (100%, 75%, 50%, 25%) impacted the strength and durability properties of the concrete. Specimens were tested to determine compressive strength, flexural strength, workability and fatigue resistance. Test results showed that mixes with 25% RAP replacement achieved strength properties closest to normal concrete. A mix with 75% natural aggregate and 25% RAP aggregate was identified as a feasible option for use in concrete pavements based on its strength performance.
Combustion refers to the rapid oxidation of fuel accompanied by heat or heat and light. Complete combustion requires an adequate oxygen supply. The objective of good combustion is to release all the heat from fuel by controlling temperature, turbulence for mixing fuel and oxygen, and reaction time. Stoichiometry calculates the theoretical air required for combustion and can determine excess air by measuring flue gas CO2 levels. A certain amount of excess air is needed for complete combustion but too much leads to heat losses.
The document defines combustion as a chemical process where a substance reacts with oxygen in air to produce heat and light. There are several types of combustion described, including spontaneous, rapid, complete, and incomplete combustion as well as explosions. Rapid combustion occurs when a substance burns quickly, producing heat and flame, often with the introduction of external heat. Incomplete combustion results in only partial burning of a fuel due to a lack of oxygen or low temperature, producing carbon monoxide. For combustion to occur, there must be a combustible substance, a supply of oxygen (air), and enough heat to raise the substance to its ignition temperature.
Petroleum coke is a byproduct of the oil refining process with a high calorific value and lower cost than coal. It can be used in cement production, with limitations on the amount used due to its high sulfur content. Using petcoke up to 24% as a substitute for existing fuel in a cement plant can maintain acceptable sulfur ratios and volatile matter levels in the clinker and coal mix, while lowering fuel costs. However, its abrasive nature and difficulty burning require modifications to equipment for effective utilization in kilns and calciners.
Land pollution occurs as a result of human activities like deforestation, overuse of chemicals, and improper waste disposal. This damages soil and reduces forest cover. Key causes are degenerative human actions, misuse of land, soil pollution, and land conversion. Effects include increased climate issues, extinction of species due to lost habitats, and disruption of food chains. To prevent further land pollution, proper waste management, recycling, reuse, and growing more trees is needed at personal and industrial levels.
This document discusses fuels and combustion. It defines fuels and combustion, describes types of fuels like solid, liquid and gaseous. It explains complete and incomplete combustion, oxidation of carbon, hydrogen and sulfur in combustion reactions. It discusses air composition, theoretical air requirements, combustion of hydrocarbon fuels. It also covers properties of fuels like heating value, viscosity and methods of determining heating value through bomb calorimeter and gas calorimeter.
This document is a presentation by Group 4 of Diploma Civil "A" on the topic of fuel and combustion. It introduces different types of fuels such as solid, liquid, and gaseous fuels. Solid fuels discussed include coal, coke, and charcoal. Liquid fuels mentioned are tar, kerosene, diesel, petrol, and gas. Gaseous fuels include natural gas, coal gas, and biogas. The presentation covers the characteristics of good fuels, classification of fuels, advantages and disadvantages of different fuel types, and concepts of combustion and calorific values. In the end, the group thanks their professor Mr. Tarang Agarwal for giving them the opportunity to present.
Load balancing in public cloud by division of cloud based on the geographical...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This document discusses using GIS to assess topographical aspects for locating infrastructure facilities in hilly regions. It notes that traditional 2D maps and sketches used by engineers do not fully consider topography. The study develops a GIS-based methodology to analyze topographical factors and locate proposed facilities at a college campus in India as a case study. The objectives are to model the existing topography and facilities in 3D using GIS to identify suitable and adverse locations for new infrastructure, allowing more sustainable development of the hilly region.
This document discusses geo-distributed parallelization of MapReduce jobs across multiple datacenters. It introduces GEO-PACT, a Hadoop-based framework that can efficiently process sequences of parallelization contracts jobs on geo-distributed input data. GEO-PACT uses a group manager to determine optimal execution paths and job managers at each datacenter to execute tasks locally using Hadoop. It employs copy managers to transfer data between datacenters and aggregation managers to combine results. The goal is to optimize execution time by leveraging data locality across geographically distributed data sources.
A batch study of phosphate adsorption characteristics on clay soileSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Design and analysis of worm pair used in self locking system with development...eSAT Publishing House
This document describes the design and analysis of a worm pair system used for self-locking. A worm pair system combines two threaded rods or worm screws that are meshed together to provide self-locking properties with over 90% efficiency, compared to around 40% for a conventional worm gear system. The design process involves selecting materials and dimensions for the input shaft, output shaft, load drum hub, and worm screws. Calculations are shown for torque capacities, shear stresses, and efficiencies. Experimental results validate that the worm pair system has higher efficiency than a conventional worm gear self-locking system. A manual clutch is also designed to allow quickly releasing the load by disengaging the load drum from the output shaft.
Automatic collision detection for an autonomous robot using proximity sensing...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This document describes an adaptive Kalman filter implementation for video denoising. It proposes processing video frames independently in the spatial domain and then applying an adaptive temporal Kalman filter to each pixel sequence to reduce complexity. An adaptive Kalman filter is used which can adjust its parameters based on noise statistics variations and detected motions between frames. The algorithm is tested through MATLAB simulation on sample video frames, showing it produces a denoised output with reduced noise while still responding to changes in pixel values over time. The design considerations for FPGA implementation focus on using fixed-point arithmetic and shift operations instead of division to optimize for the FPGA hardware.
This document presents a new economical and time-saving method for concrete dosing based on particle packing principles. The method treats water requirements separately for each concrete constituent and uses a specific mixing sequence. Testing showed concrete produced with this new method achieved 54MPa compressive strength at 28 days using 30% less cement than a standard ABCP method concrete that achieved only 43MPa. The new method provides stronger concrete with lower cement content in a more efficient process.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Determining the rheological properties of asphalt binder using dynamic shear ...eSAT Journals
This document summarizes a study that determined the rheological properties of asphalt binder extracted from different sections of a four-year-old flexible pavement using a Dynamic Shear Rheometer (DSR). The pavement was divided into six sections based on surface course thickness. Binder was extracted and tested using the DSR to determine properties like complex modulus, elastic and viscous modulus, complex viscosity, and phase angle. These properties indicate the sections' resistance to rutting and fatigue cracking. Test results found the 60/70 grade binder provided sufficient stiffness to resist rutting and fatigue failure under existing pavement conditions.
Determining the rheological properties of asphalt binder using dynamic shear ...eSAT Journals
Abstract
This paper aims to study the rheological properties of the binder taken from four years old flexible pavement stretch. The stretch was
divided into six different sections based on the thickness of the surface course. Originally, 60/70 grade asphalt binder was used
throughout the pavement stretch. The binder was obtained from the process of extraction and recovery. Dynamic shear rheometer
(DSR) test was conducted on the recovered asphalt binder to determine the various parameters viz., Complex modulus G*, Elastic and
viscous modulus, Complex viscosity and the phase angle δ. The major pavement distress modes namely, rutting and fatigue cracking
were addressed by these output parameters of DSR. Rutting is caused by permanent deformation of paving mix while fatigue is related
to the energy absorbed during repeated load application to pavement. The test results indicated that the 60/70 binder extracted from
the selected stretches were stiff enough to resist rutting and fatigue failure.
Multiscale Modeling Approach for Prediction the Elastic Modulus of Percolated...ijtsrd
In this study the effective elastic modulus of cellulose nanocrystal CNC network is evaluated using multiscale method and micromechanical analysis. For this purpose, the elastic modulus of CNC water phases are randomly assigned to a two dimensional 2D checkerboard structure and the elastic response is evaluated. In addition, the effect of having a different number of phases CNC, water and interface is evaluated by assigning a discreet and continuous distribution of elastic modulus to checkerboard structure. When the number of phases increases dramatically, the distribution of phases is continuous and is defined with Weibull distribution. The results show that for two phase materials CNC and water when the microstructure has organized pattern the rule of the mixture and numerical model provide the same effective modulus, however when the microstructure is completely random, the self consistent micromechanical model should be used. Also, this study suggests 50 volume fraction as the percolation threshold for the CNC network with 10 GPa effective elastic modulus. The results from percolated multiphase network reveal that for microstructures with 4 phases and above, the percolated network converge to 35 GPa. Mehrdad Bor | Jim Huang "Multiscale Modeling Approach for Prediction the Elastic Modulus of Percolated Cellulose Nanocrystal (CNC) Network" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26553.pdfPaper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/26553/multiscale-modeling-approach-for-prediction-the-elastic-modulus-of-percolated-cellulose-nanocrystal-cnc-network/mehrdad-bor
Structural design and economic evaluation of roller compacted concrete pavementSalih Taner YILDIRIM
Abut, Y., & Yildirim, S. T. (2017, October). Structural design and economic evaluation of roller compacted concrete pavement with recycled aggregates. In IOP Conference Series: Materials Science and Engineering (Vol. 245, No. 2, p. 022064). IOP Publishing.
The document presents the results of a study investigating the use of shredded scrap tires as an alternative to gravel in the drainage layer of a landfill leachate collection system. Mathematical models were developed to predict the effluent-influent ratios of various physico-chemical parameters of leachate after passing through combined beds of scrap tire shreds and gravel. The models showed good agreement with experimental data. The study found that a combination of scrap tire shreds and gravel improved the reduction of leachate parameters compared to using either material alone. This supports the potential use of scrap tires as a beneficial material in leachate treatment and management of tire waste.
IRJET- Effect of Soil- Structure Interaction on Response of Building Frame...IRJET Journal
This document analyzes the effect of soil-structure interaction on the response of a three-story building frame supported by a piled-raft foundation. A finite element model is developed to model the frame, slab, beams, columns, piles, raft, and soil. Parametric studies are conducted to evaluate the effect of raft thickness and pile diameter on frame displacements. The key findings are that considering soil-structure interaction increases frame displacements compared to assuming a fixed base, and displacements decrease with increasing pile diameter and raft thickness due to improved soil resistance. Nonlinear soil behavior further reduces displacements compared to linear analysis.
Application of Geosynthetics in Pavement DesignIRJET Journal
This document summarizes research on using geosynthetics like geogrids and geotextiles in pavement design. It discusses how geosynthetics can improve load distribution and reduce stresses on subgrade layers through mechanisms like confinement and interlocking. The document reviews literature showing geogrids can allow up to 40% reduction in base course thickness and increase the number of load cycles pavements can withstand by 1.5 to 3 times. It also discusses guidelines for selecting and placing geogrids to maximize reinforcement benefits, like placing them near the top of base layers. In summary, the document outlines how geosynthetics can provide a more cost-effective way to strengthen pavements through reinforcement.
This document proposes a Mesh Superposition Technique (MST) to couple differently discretized subdomains in a finite element model. The MST replaces interfaces between subdomains with transition regions where the meshes are superposed. Weighting factors are used to blend the material properties and boundary conditions in the overlapping transition regions. The MST is applied to simulate low-velocity impact damage in a composite plate, eliminating stress disturbances at discretization interfaces compared to abrupt transitions. When used for multiple time/length scale analysis, the MST reduces CPU time by nearly half compared to sudden discretization transitions.
The document discusses finite element modeling of piled raft foundations in sand using MIDAS GTS software. It analyzes unpiled and piled raft foundations with different sizes and thicknesses, subject to various vertical load intensities. For unpiled rafts ranging from 8x8m to 15x15m, normalized settlement values ranged from 1.03-1.17mm and 0.66-0.83mm respectively. Piled raft analyses with 8x8m rafts and 0.25-3m thicknesses resulted in maximum settlements of 66-63mm. Parametric studies examined effects of raft thickness, pile spacing, number of piles, and loading on settlement behavior. Results provide design
This document summarizes research on developing a multi-scale modeling approach to predict the structural behavior of carbon fiber reinforced composite pipes used for offshore oil and gas risers. The approach models the pipe behavior at the micro, meso, and macro scales and links the scales together. Experiments were conducted to validate the modeling approach and determine material properties at each scale. Results showed good agreement between predicted and experimental properties and structural response at different loading conditions. The multi-scale modeling approach shows promise for designing composite risers while addressing current limitations in experience, standards, and design methodologies.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document introduces a multiple length/time-scale framework for virtual testing of large composite structures. The framework uses a Mesh Superposition Technique (MST) to couple areas modeled at different length-scales. It also uses an efficient solid-to-shell numerical homogenization that exploits internal symmetries of Unit Cells (UCs) to minimize computationally demanding areas and costs. The framework allows modeling different parts of a structure using different solvers depending on computational efficiency. The relevance and key aspects of the framework are demonstrated through analysis of a real aeronautical composite component.
This document describes a study that uses finite element analysis to develop an alternative method for analyzing rigid pavements. The study uses the commercial FEM software LUSAS to model a two-layer pavement system under single-wheel loading conditions. Results for flexural stresses are compared between plane strain and axisymmetric models, as well as with results from the Portland Cement Association design method. An example problem is presented to illustrate how FEM can be used for rigid pavement analysis and design.
A new proposed approach for moment capacity estimation of ferrocement members...Pouyan Fakharian
Ferrocement composites are widely used as a novel method for many different structural purposes recently. The uniform distribution and the high surface area-to-volume ratio of the reinforcement of such composites would improve the crack-arresting mechanism. Given these properties, ferrocement is an ideal option as a replacement for some traditional structures methods. In members with axially loaded reinforced concrete ferrocement composite, it would be the best alternative to use ferrocement members. Lack of sufficient research in this approach is the cause of not well defining this field for RC structures. This study has aimed to evaluate the moment capacity of ferrocement members using the GMDH method. Mechanical and geometrical parameters including the width of specimens, total depth specimens, compressive strength of ferrocement, ultimate strength of wire mesh and volume fraction of wire mesh are considered as inputs to predict the moment capacity of ferrocement members. For evaluating this model, mean absolute error (MAE), root mean absolute error (RMAE), normalized root mean square error (NRMSE) and mean absolute percentage error (MAPE) were carried out. The results conducted that the GMDH model is significantly better than some previous models and comparable to some other methods. Moreover, a new formulation for moment capacity of ferrocement members based on GMDH approach is presented. Finally, Sensitivity analysis is operated to understand the influence of each input parameters on moment capacity of ferrocement members.
Due to increase in construction activities there is increase in demand for concrete, which leads to over use of natural resource. Hints, conservation of natural resource is necessary thing. Among the waste generated it is presumed that 10% to 15% of waste hazardous and increasing at the rate of 2% to5% per year resulting in environmental pollution and effect to living beings. These wastes can be utilized as alternative construction material, so that would be one of the consistent ways of disposal. This paper attempts to study the strength parameters such as compressive and tensile strength of paper sludge ash (15% and 20%) as partial replacement of cement, M-sand (50% and 60%) of partial replacement of fine aggregate for a design mix of M25.
Performance evaluation of dense bituminous macadam mix a refusal density ap...eSAT Journals
Abstract
Secondary compaction is a state; where the pavement which is compacted with the conventional compaction has been further
compacted due to the movement of traffic and which corresponds to the ultimate density which can be attained on the bituminous
pavement called as “Refusal density” of the pavement. Secondary compaction has to be studied in detail and it is understood that the
75 blows of the Marshall test does not determine the actual field circumstances. The Marshall design actually in the field will not
simulate the field conditions hence there will be a reduction in the air voids at the refusal density. Then due to fineness of the mix, this
causes the plastic deformation on the pavement surfaces. Hence an attempt has been made to study the air void content at refusal
density. Also the Bulk Density, Air voids (Va), Voids in mineral aggregate (VMA),Voids filled with Bitumen (VFB) of the mix at the
refusal density are also studied. For the simulation of the field density in the laboratory a Hugo hammer is used. The usage of the
Polymer Modified Bitumen reduces the plastic deformation and other distresses of the pavement.
Keywords: Dense bituminous macadam (DBM), Refusal density, Hugo hammers.
This document evaluates the performance of dense bituminous macadam mix using a refusal density approach. It summarizes the objectives of determining the optimum bitumen content using polymer modified bitumen and Hugo hammer compaction. It also aims to study mix properties at refusal density and compare Marshall properties using Hugo hammer and standard compaction. The literature review covers limitations of the Marshall design method in not simulating field conditions. The document outlines the aggregate properties, mix design, and laboratory investigations conducted. Test results found the air void content at refusal density to be 3.76% and established 200 blows as the refusal density. Properties varied with compaction effort, establishing the refusal density approach better simulates field conditions compared to the standard Marshall method.
Experimental Study on Pavement Stabilization Using Geosynthetic SolutionIRJET Journal
This document summarizes an experimental study on using geosynthetic materials to stabilize pavement. Specifically, it examines using extruded biaxial polypropylene geogrid at the interface of granular sub-base and base layers of a pavement section. The geogrid is proposed to increase the modulus of the granular layers, thereby reducing the required thickness of asphalt and granular layers. A literature review found that geogrid reinforcement can decrease vertical strain and reduce horizontal tensile strain in asphalt pavements. A trial section was designed with geogrid placed between granular base and sub-base layers according to IRC guidelines. Material properties of the subgrade soil, granular layers, asph
Similar to Packing issue in cement blending for sustainability developments approach by discrete element method (20)
Hudhud cyclone caused extensive damage in Visakhapatnam, India in October 2014, especially to tree cover. This will likely impact the local environment in several ways: increased air pollution as trees absorb less; higher temperatures without tree canopy; increased erosion and landslides. It also created large amounts of waste from destroyed trees. Proper management of solid waste is needed to prevent disease spread. Suggested measures include restoring damaged plants, building fountains to reduce heat, mandating light-colored buildings, improving waste management, and educating public on health risks. Overall, changes are needed to water, land, and waste practices to rebuild the environment after the cyclone removed green cover.
Impact of flood disaster in a drought prone area – case study of alampur vill...eSAT Publishing House
1) In September-October 2009, unprecedented heavy rainfall and dam releases caused widespread flooding in Alampur village in Mahabub Nagar district, a historically drought-prone area.
2) The flood damaged or destroyed homes, buildings, infrastructure, crops, and documents. It displaced many residents and cut off the village.
3) The socioeconomic conditions and mud-based construction of homes in the village exacerbated the flood's impacts, making damage more severe and recovery more difficult.
The document summarizes the Hudhud cyclone that struck Visakhapatnam, India in October 2014. It describes the cyclone's formation, rapid intensification to winds of 175 km/h, and landfall near Visakhapatnam. The cyclone caused extensive damage estimated at over $1 billion and at least 109 deaths in India and Nepal. Infrastructure like buildings, bridges, and power lines were destroyed. Crops and fishing boats were also damaged. The document then discusses coping strategies and improvements needed to disaster management plans to better prepare for future cyclones.
Groundwater investigation using geophysical methods a case study of pydibhim...eSAT Publishing House
This document summarizes the results of a geophysical investigation using vertical electrical sounding (VES) methods at 13 locations around an industrial area in India. The VES data was interpreted to generate geo-electric sections and pseudo-sections showing subsurface resistivity variations. Three main layers were typically identified - a high resistivity topsoil, a weathered middle layer, and a basement rock. Pseudo-sections revealed relatively more weathered areas in the northwest and southwest. Resistivity sections helped identify zones of possible high groundwater potential based on low resistivity anomalies sandwiched between more resistive layers. The study concluded the electrical resistivity method was useful for understanding subsurface geology and identifying areas prospective for groundwater exploration.
Flood related disasters concerned to urban flooding in bangalore, indiaeSAT Publishing House
1. The document discusses urban flooding in Bangalore, India. It describes how factors like heavy rainfall, population growth, and improper land use have contributed to increased flooding in the city.
2. Flooding events in 2013 are analyzed in detail. A November rainfall caused runoff six times higher than the drainage capacity, inundating low-lying residential areas.
3. Impacts of urban flooding include disrupted daily life, damaged infrastructure, and decreased economic activity in affected areas. The document calls for improved flood management strategies to better mitigate urban flooding risks in Bangalore.
Enhancing post disaster recovery by optimal infrastructure capacity buildingeSAT Publishing House
This document discusses enhancing post-disaster recovery through optimal infrastructure capacity building. It presents a model to minimize the cost of meeting demand using auxiliary capacities when disaster damages infrastructure. The model uses genetic algorithms to select optimal capacity combinations. The document reviews how infrastructure provides vital services supporting recovery activities and discusses classifying infrastructure into six types. When disaster reduces infrastructure services, a gap forms between community demands and available support, hindering recovery. The proposed research aims to identify this gap and optimize capacity selection to fill it cost-effectively.
Effect of lintel and lintel band on the global performance of reinforced conc...eSAT Publishing House
This document analyzes the effect of lintels and lintel bands on the seismic performance of reinforced concrete masonry infilled frames through non-linear static pushover analysis. Four frame models are considered: a frame with a full masonry infill wall; a frame with a central opening but no lintel/band; a frame with a lintel above the opening; and a frame with a lintel band above the opening. The results show that the full infill wall model has 27% higher stiffness and 32% higher strength than the model with just an opening. Models with lintels or lintel bands have slightly higher strength and stiffness than the model with just an opening. The document concludes lintels and lintel
Wind damage to trees in the gitam university campus at visakhapatnam by cyclo...eSAT Publishing House
1) A cyclone with wind speeds of 175-200 kph caused massive damage to the green cover of Gitam University campus in Visakhapatnam, India. Thousands of trees were uprooted or damaged.
2) A study assessed different types of damage to trees from the cyclone, including defoliation, salt spray damage, damage to stems/branches, and uprooting. Certain tree species were more vulnerable than others.
3) The results of the study can help in selecting more wind-resistant tree species for future planting and reducing damage from future storms.
Wind damage to buildings, infrastrucuture and landscape elements along the be...eSAT Publishing House
1) A visual study was conducted to assess wind damage from Cyclone Hudhud along the 27km Visakha-Bheemli Beach road in Visakhapatnam, India.
2) Residential and commercial buildings suffered extensive roof damage, while glass facades on hotels and restaurants were shattered. Infrastructure like electricity poles and bus shelters were destroyed.
3) Landscape elements faced damage, including collapsed trees that damaged pavements, and debris in parks. The cyclone wiped out over half the city's green cover and caused beach erosion around protected areas.
1) The document reviews factors that influence the shear strength of reinforced concrete deep beams, including compressive strength of concrete, percentage of tension reinforcement, vertical and horizontal web reinforcement, aggregate interlock, shear span-to-depth ratio, loading distribution, side cover, and beam depth.
2) It finds that compressive strength of concrete, tension reinforcement percentage, and web reinforcement all increase shear strength, while shear strength decreases as shear span-to-depth ratio increases.
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Packing issue in cement blending for sustainability developments approach by discrete element method
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PACKING ISSUE IN CEMENT BLENDING FOR SUSTAINABILITY
DEVELOPMENTS - APPROACH BY DISCRETE ELEMENT METHOD
Nghi L.B. Le1
, Piet Stroeven2
1
Delft University of Technology, Faculty of Civil Engineering and Geosciences, Delft, the Netherlands
2
Delft University of Technology, Faculty of Civil Engineering and Geosciences, Delft, the Netherlands
Abstract
Common cement blending materials for concrete like fly ashes, blast furnace slag, silica fume, metakaolin and rice husk ash have
been investigated experimentally as to their impact on concrete’s mechanical, physical and sustainability capabilities. Such
efforts offer but case-related information on involved materials and used procedures. Generalizations will be difficult because
also contradicting information is provided: a weak basis to guide further developments. Published research data on blends with
inert components (carbon black) confirm fineness to be the leading parameter governing their mechanics. Experimental efforts
revealing blending effects on durability issues are more scarce because of their complicated, laborious and time-consuming
nature. Hence, generalization capabilities are even more restricted. An approach is therefore presented for studying cementitious
materials in the virtual reality, employing the concurrent algorithm-based dynamic discrete element method (DEM), HADES.
Hydration simulation of the simulated (blended) Portland cement grain mixture is thereupon accomplished with an extended
version of the vector approach. Robotics-based pore delineation provides topological information, while geometric
characterization of the pore networks is accomplished by star volume measurements. Topological and geometric parameters can
be combined in a hydraulic model for durability estimation. This approach allows covering a wide range of parameters. This
would render possible more systematic and economic development of such materials for sustainability purposes, among other
things. The production stages (DEM and hydration simulation) and the analysis stages (pore delineation and topology and
geometry assessment) are briefly outlined. Application of the methodology is illustrated on finer and coarser grained cements
blended with rice husk ash produced with different fineness. The effects of the gap in grading on the pore network characteristics
relevant for transport-based durability items are outlined.
Keywords: Cement blending, particle packing, hydration, discrete element method, porosimetry, transport-based
durability.
---------------------------------------------------------------------***---------------------------------------------------------------------
1. INTRODUCTION
Common cement blending materials for concrete like fly
ashes, blast furnace slag, silica fume, metakaolin and rice
husk ash have been investigated experimentally as to their
impact on concrete’s mechanical, physical and
sustainability capabilities. Such efforts offer but case-related
information on involved materials and used procedures.
Generalizations will be difficult because also contradicting
information is provided. This constitutes a weak basis to
guide further material developments that would fulfil
sustainability requirements. Portland cement production
significantly contributes to worldwide CO2 emissions [1].
Hence, partial replacement of Portland cement (PC) by
waste components would have direct positive sustainability
effects. In that respect, the calcined clays can be added to
the aforementioned list as artificial pozzolanas. Kaolinite,
thus obtained, derives its potentialities primarily from the
metakaolin it contains. The commercial metakaolin is much
finer, however also (far) more expensive. Yet, fineness plays
an important role in all blends. In the same way the kaolin is
calcined, diatomite can be obtained in amorphous state when
properly produced, but it contains smaller amounts of
alumina. Yet, for identical production conditions (including
the grinding period) we found about similar strength in
comparable situations due to the finer-grained diatomite [2-
3]. All these blending components manifest natural or
artificial pozzolanic properties that can compensate for the
reduced chemical potentials of the PC in the blend.
Published research data on blends with inert components
(carbon black) con-firm fineness to be the leading parameter
governing their mechanics [4]. With the fineness of the
carbon black attuned to that of the Portland cement (so,
leading to optimum packing), it was found that in the high
quality range the reduced chemical capabilities could be
fully compensated by the physical contributions to strength.
Experimental efforts revealing blending effects on durability
issues are scarcer because of more complicated, laborious
and time-consuming nature. As an example, see [5-6]. Yet,
it becomes apparent from the literature that more efficient
binder packing in the fresh state will lead to a denser hydrate
structure and thus reduced pore dimensions [7]. This would
make the concrete less accessible for both gasses and fluids
that are harmful to concrete’s integrity. So, particle packing
should be considered a relevant issue in designing blends for
promoting sustainability, among other things [8].
Generalizations can nowadays more easily be made by
studying virtual cementitious materials [9-15]. Of course,
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 90
the reliability of the research outcomes will depends on the
quality -for the objected purpose- of the simulation system
[16]. The popular random sequential addition (RSA)
systems in concrete technology should be avoided, since
pore network characteristics will depend on the particle
dispersion in the virtual material. This is biased in RSA
systems [17-18]. Hence, DEM, either of static or of dynamic
nature, should be selected for the present purpose. DEM
simulations by a versatile system like HADES make it
possible producing realistic representations of cementitious
materials on different structural levels. Aggregate grains of
fluvial origin or of crushed rock can be packed according to
respective sieve curves into the dense random packing state
[19]. Such experiments on meso-level yield information on
surface spacing and thus on the extent of the binder that is
pocketed between the aggregate surfaces. On micro-level
the binder grains are thereupon packed in containers of
appropriate size. Two rigid container surfaces may represent
the aggregate surfaces that induce gradient structures, which
are denoted as Interfacial Transition Zones (ITZs) [20-21].
Next, hydration simulation is accomplished by an extended
version of the vector approach [22]. Robotics-based pore
delineation provides topological information, while
geometric characterization of the pore network is
accomplished by star volume measurements [14,23].
Topological and geometric parameters can be combined in a
hydraulic model for durability estimation. This approach
renders possible covering in an economic way a wide range
of parameters. This paper will apply the sketched DEM
approach to gap-graded RHA blends, whereby the gap is
varied in intensity.
2. METHODOLOGY IN VIRTUAL REALITY
The details of the various blocks of the methodology for
porosimetry are explicitly described in the international
literature. Successively, these blocks concern
1) HADES: dynamic DEM for packing simulation of
artificially-shaped particles on meso-, micro- and
nano-level [19];
2) XIPKM: extended integrated particle kinetics
method for simulation of fresh multi-component
blended cement system [22]; the IPKM reference
method is described in [12,24];
3) DRaMuTS: double random multiple tree structuring
system for delineating the complete pore network
system and for topology assessment [14];
4) SVM: star volume measurements in uniformly
random point system inside the pore network
[14,23];
5) Tube model: the tree data obtained by DRaMuTS
are employed to construct a network of cylindrical
tubes connected at nodes that represents the
percolated pore system; by applying a pressure
gradient across the ends of the network, permeability
is determined [13,25].
Hence, interested readers can find all computational details
on algorithms in the indicated international literature.
Globally speaking, the sequence of activities encompassed
the following. A Rosin-Rammler function is specified to
repre-sents the size distribution of the Portland cement; i.e.,
G(d)=1-exp(-bda
), whereby G(d) stands for the mass or
volume fract-ion of the cement passing a sieve with opening
d, and a and b are constants [26]. Mineral admixture
particles may have their own grain size distribution. The
amount of particles necessary to achieve pre-determined
water to binder ratio and blending percentage is assessed
and dispersed by RSA in a large container, generally with
two rigid and four periodic boun-daries. Particles are set to
linearly move and rotate according to Newtonian rules.
Overlap is avoided by having a thin boundary layer of
constant thickness enveloping the particles.
Local overlap of such boundary zones activates associated
surface elements of the particles. Depending on total
involved surface area and degree of overlap, an integrated
reaction is generated that forces the particles to separate
again. Also the container surface is covered by such a thin
boundary zone. The container size is gradually reduced until
the w/c ratio is achieved, whereupon motion stops.
The major compounds of the PC and of the mineral
admixture (basically SiO2 representing RHA) are reacting
according to standard chemical equilibrium reactions that
also involve volume changes. Once the original size of the
PC grains is exceeded after formation of CSHin layer,
deposition in smooth layers of CSHout is continuing, thereby
expanding the particles and leading to complicated
interactions among hydrating neighbouring particles. This is
modelled in XIPKM. Set up and verification results are
shown in Figs. 1 and 2.
Pore characteristics in 3D virtual hydrated cementitious
paste are investigated by the DRaMuTS method that has
been introduced in Stroeven et al. By this method,
randomized data structures are built incrementally in two
stages. The first stage is to rapidly explore the pore space; a
system of virtual trees, which consist of nodes and lines
connecting pairs of such nodes (like branches in real trees),
randomly and increment-tally grow in the pore medium. To
speed up the process, deviating from algorithms developed
in robotics, a point is shifted to avoid rejections, thereby
however violating the uniform randomness of the tree
system. When neighbouring trees are developing in the same
pore, they will merge. In the second stage, a system of
probing points is generated uni-formly at random (UR) in
pore space. As a result, such points can be used for
statistical assessment of pore characteristics in which point
classifications are realized by connections of such points to
the tree systems. For example, the connected fraction of
pores can be estimated by the fraction of the total number of
points that can be associated with the percolated tree
branches.
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Fig. 1: (top) particle models of 2-compound cement,
pozzolanic admixture and hydration product; (bot-tom)
differently color-coded microstructure.
Pore size distribution (PoSD) is obtained from SVM where
the system of UR points is employed as the nuclei of
“stars”. In each point a system of pikes is generated
isotropic uniformly at random (IUR) or in systematic
directions. Length of a pike, li, spanning in an unobstructed
way the distance from the star’s nucleus to the nearest pore
surface, is assessed. In 3D space,
33
i i2d l , whereby di is
an unbiased estimate of local pore size. Such star volume
measurements (SVM) in the star nuclei provide the
information for the construction of the 3D volume-based
pore size distribution. Alternatively, a plane is located
through a nucleus and pikes are, e.g., designed in uniform
directions in the plane section. The area of this pore section
is estimated by Ai=
2
1l , with li as the unobstructed distance
from the nucleus to the nearest pore perimeter. By rotating
the plane section, the minimum value of Ai can be
determined. This is denoted the pore throat. The
aforementioned adjust-ment of sensitivity to a relevant
engineering level involves eliminating all throat areas
smaller than a minimum value.
20% cement replacement
Fig. 2: Porosity of the RHA-blended PC samples (for
experimental results, see Nguyen [27]. RHA-blended PC
samples with w/b = 0.4 and 10-20% replacement). Hydrated
with XIPKM.
When the trees in DRaMuTS span the full dimensions of the
cube, the so-called “main trunks” are extracted from the tree
system. Such main trunks represent the direct paths (tracks)
through pore space from the bottom to the top of the sample.
Next, the main trunks are smoothed to reflect the flow
length. Illustrations of main trunk extraction and smoothing
are shown in Fig. 3. This extraction defines the skeleton of
the pore network. For other methods for skeletonization , see
[28-29].
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Fig. 3: (top) Picture of main trunks in 2D (bold lines) that
are derived from tree branches; (bottom) Picture at the right
shows trunks after smoothing.
Finally, a network structure of cylindrical tubes and nodes is
constructed to represent the smoothed main trunks. The
diameters of the tubes are derived from SVM along the
length of the main trunks. The flow inside a tube is assumed
to be slow, saturated, incompressible and laminar according
to the Hagen-Poiseuille law. This structure is supposedly
subject-ed to a given pressure gradient between at inlet and
outlet nodes. Applying the volume conservation law at
nodes between two or more tubes, a set of algebraic
equations is obtained with nodal pressures as unknowns.
After solving this set of equation, the permeability is
estimated by Darcy’s equation:
u L
K
P
(1)
where K = permeability [m2
], u = average velo-city
[m/s], L = sample length [m], µ = dynamic viscosity of the
intruding fluid [N.s/m2
], and P = applied pressure gradient
[N/m2
].
3. ILLUSTRATIVE BLENDING EXAMPLES
3.1 Materials and Experimental
Reference PC composition: 100% C3S. Blaine fine-ness
300m2
/kg. Rosin-Rammler particle size distribution with a
= 1.107 and b = 0.023. The following PC fractions are taken
from this reference cement.
.
Fig. 4: (top) PSD of the materials: Portland cement (PC) and
rice husk ash (RHA). (bottom) Median particle sizes of
various blended mixtures (w/b=0.4, RHA18, 20%
replacement)
Cem133, Cem240 and Cem350 with size ranges 1~33 m,
2~40 m and 3~50 m, respectively. RHA: SiO2 and inert
component [8,30]; RHA14: grinding time 14 h; RHA18:
grinding time 18 h; RHA18+: grinding time 18 h with
grinding aid. Cubic samples of (blended) PC are simulated
with 100-150 m side length and two opposite rigid
boundaries and four periodic ones.
Purpose is to have cements with different fineness partially
replaced by rice husk ashes of different fineness that
resulted from modified grinding procedure. Result is gap-
0 5 10 15 20 25 30 35 40 45 50
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Particle size (m)
Cummulativepercentagebyweight
Cem133
Cem240
Cem350
RHA18+
RHA18
RHA14
Cem133 Cem240 Cem350
0
2
4
6
8
10
12
14
16
18
20
Medianparticlesize(m)
plain
blended
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grading to different degrees. Fig. 4 displays the particle size
distributions (PSD) of the blending components. Mixtures
will have as a result different median particle size as shown
in Fig. 4 at the right. The effect of the resulting “gap” on
pore refinement and ITZ reduction due to blending will be
investigated.
3.2. Results
Fig. 5 shows the network of delineated pores (top) and of the
main trunks connecting opposite outer surfaces of the
specimen.
Fig. 5: Pore delineation in 100μm cubes for a plain PC
sample. All trees growing in capillary pores are shown (top)
as well as the extracted main trunks only (bottom). Visually
similar results were obtained for blended specimens.
Fig. 6: Porosity evolution in time by hydration of cubic
samples with different side lengths (cement size range of 3
~33 µm; six periodic boundaries)
Fig. 7: ITZ thickness versus median particle size of samples
with different blending dosage of RHA (Cem133, w/b = 0.4
and RHA18+) (top) and with different type of RHA
(Cem133, w/b = 0.4 and 20% blending) (bottom).
Fig. 6 demonstrates the 100μm cube of representative size
for pore evolution. This was also confirmed on the basis of
other parameters in the experimental approach. Figs. 7 and 8
10
0
10
1
10
2
10
3
10
4
10
5
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
time (hours)
poro(%)
100m
150m
200m
7 8 9 10 11 12 13 14 15
5
6
7
8
9
10
11
12
13
14
plain
10%RHA
20%RHA
30%RHA
Median particle size (m)
ITZthickness(m)
9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 14.5
5
6
7
8
9
10
11
12
13
14
Cem133
Cem133+20%RHA14
Cem133+20%RHA18
Cem133+20%RHA18+
Median particle size (m)
ITZthickness(m)
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demonstrate the ITZ reduced and its pore fraction
diminished with increasing the size of the gap, whereas the
ITZ in plain cement contains relatively high fraction of
larger pores. Figs. 9 and 10 witness the pore refinement that
occurs due to increasing gap-grading.
Fig. 8: Pore fraction in ITZ of samples with different type of
RHA (Cem133, w/b = 0.4 and 20% blending) (top) and with
different cements fineness (w/b = 0.4, RHA18+ and 20%
blending)
Fig. 9: Pore throat size distribution of samples with different
type of RHA (Cem133, w/b = 0.4 and 20% blending) (left)
and of plain and blended samples with different cement size
ranges (w/b = 0.4, RHA18+ and 20% blending) (right).
4. CONCLUSIONS
The presented methodology offers a reliable and economic
way to study in a systematic way transport-based durability
issues, since the underlying pore network topology and
geometry can readily be obtained. In designing mono-
blends or hybrid ones, fineness is a leading parameter.
Particularly in the high performance range, van der Waals
contributions to strength can be significant when particle
packing is improved/optimized by blending. Packing optimi-
zation exceeds the importance of the degree of pozzolanity.
plain RHA14 RHA18 RHA18+
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
Cem133 Cem350
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
plain
blended
0 1 2 3 4 5 6 7 8 9
0
5
10
15
20
25
30
35
40
45
Pore throat size (m)
Volume-basedporedensity(%)
plain
RHA14
RHA18
RHA18+
0 2 4 6 8 10 12 14
0
5
10
15
20
25
30
35
40
45
Pore throat size (m)
Volume-basedporedensity(%)
Cem133,plain
Cem133,blended
Cem240,plain
Cem240,blended
Cem350,plain
Cem350,blended
7. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 95
Fig. 10: Median pore size and permeability K vs. median
pore size of plain and blended samples (data are collected
from different samples with w/b=0.4).
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6 8 10 12 14 16 18 20
2
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Median particle size (m)
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Median particle size (m)
K(m2)
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8. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 96
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BIOGRAPHIES
Obtained his MSc from Ho Chi Minh
City University, Vietnam. Presently,
PhD candidate in Computational
Mechanics group at Delft University of
Technology. His research interests
focus on computational modelling of
construction materials and structures
Retired Professor in Material
Engineering and Delft University of
Technology where he also received his
PhD. He published widely in areas
ranging from structural engineering to
materials science, predominantly in the
concrete field