This document discusses the effect of different curing methods on the compressive strength and microstructure of alkali-activated ground granulated blast furnace slag (GGBS) paste. It finds that water curing results in the highest compressive strengths. Compressive strength increases with curing time for all methods, but increases less for heat curing. Heat curing is also found to cause microcracking and surface cracks. Higher alkali content generally leads to higher strengths, with the maximum achieved with 10.41% alkali content under water curing. Controlled curing strengths increase with higher relative humidity levels.
A Review On Development Of Flyash Based High Strength Geopolymer Concretecedmmantc5411
Geopolymer concrete is the latest development in the field of concrete technology and it is still
developing. Geopolymers are inorganic, stable, hard and non-inflammable binder. The application of
geopolymer binder are in fire resistance fiber composite, sealant industry, tooling aeronautics SPF aluminium,
foundry equipment’s, radioactive toxic waste, ceramic, bricks and other precast concrete. The current review is
aims to put forward the development in geopolymer concrete for the production high strength geopolymer
concrete having strength more than 90MPa. The development of high strength concrete is aimed to reduce
structural member sizes and for economical construction in case of long span bridges and tall buildings. Also
the use flyash in concrete to reduce green gas house emission into the atmosphere by reducing cement usage
This research represents an experimental study on influence of urea on concrete through various tests on urea, cement, concrete and water. Test of finesses modulus, slump test, carbonation test, pH test, urea ingression test and increase in strength with urea percentage .This study deals to overcome three major problems in the concrete namely heat of hydration, permeability, and corrosion of steel bar embedded in concrete. Urea can generally reduce the temperature of concrete both at casting phase and during the procedure of hydration. Urea does not opposite effect the durability of reinforced concrete, except where there is an accumulation of urea crystal growth. Er. Babita | Mr. Ravi Prakash Sharma | Mr. Vikram | Dr. D. K. Gupta ""Influence of Urea on Concrete"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30172.pdf
Paper Url : https://www.ijtsrd.com/engineering/civil-engineering/30172/influence-of-urea-on-concrete/er-babita
This document summarizes a study on the strength and shrinkage properties of alkali-activated slag concrete (AASC) placed in a large concrete column. Key findings include:
1) The AASC had improved workability over time compared to ordinary portland cement concrete, with minimal slump loss over 2 hours.
2) The temperature development in the AASC column was similar to a blended cement column and slower than an ordinary portland cement column, with a smaller temperature difference between the interior and exterior.
3) The compressive strength of the AASC column was identical to ordinary portland cement concrete and stronger than blended cement concrete at 28 and 91 days.
4) Embedded strain gauges
This document summarizes a study on the effect of sulphuric acid in water on the strength of blended cement concrete. Concrete cubes were produced using mixing and curing water with varying concentrations of sulphuric acid from 100-900 mg/L. The compressive strengths at 28 and 90 days were evaluated and decreased with increasing acid concentration. Regression models were developed that can predict the compressive strength based on the sulphuric acid concentration in water. The setting times of the blended cement also increased significantly with concentrations over 300 mg/L. In conclusion, higher sulphuric acid concentrations in water were found to reduce the strength of blended cement concrete.
Statistical modeling to forecast the strength of concrete using accelerated c...eSAT Journals
Abstract It is very much necessary to know the performance of the concrete mix before their actual use on site. The fact that all the required readings of concrete are only obtained after 28 days of curing which becomes a constraint when various grades of concrete are to be used in the same work. Accelerated curing of concrete is a good solution in such cases. IS 9013-1978 gives detailed description as well as guidelines to be adopted during the process of accelerated curing along with an equation to predict the 28 days strength of the concrete. An equation which predicts the achievable strength of concrete under normal curing by using the accelerated curing strength as the dependent parameter is available in the IS code. In this paper we have analyzed the reliability of the equation when additives such as fly ash are used in the mix. At the end it was found that the predicted values largely varied from the actual values obtained from the IS code. In this paper an effort is made to form a new equation by using 3 independent variables such as the fly ash content, water-cement ratio and the accelerated curing strength to obtain fairly reliable results. Key Words: Statistical modelling, Regression, Strength of concrete, Accelerated curing, fly ash
IRJET-Study on Strength and Durability Aspects of Geopolymer ConcreteIRJET Journal
This document summarizes a study on the strength and durability properties of geopolymer concrete using fly ash and ground granulated blast furnace slag (GGBS) as binders to replace cement. Various mix designs were tested with different ratios of fly ash to GGBS. The compressive strength and split tensile strength of the geopolymer concrete cubes increased with an increasing percentage of GGBS in the mix. The highest compressive strength of 66MPa was observed for a mix with a 60% fly ash and 40% GGBS ratio. Additionally, sorptivity tests found that geopolymer concrete has lower water absorption than traditional concrete, indicating better durability. The study demonstrates that geopolymer concrete
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Study on Alkali-Activated Concrete Containing High Volume GGBS with 30% Cemen...IJERA Editor
This document summarizes a study on alkali-activated concrete containing high volumes of ground granulated blast furnace slag (GGBS) as a partial replacement for cement. The study investigated the workability and mechanical properties of alkali-activated concrete mixtures containing 30% less cement replaced by GGBS. The GGBS was activated using sodium hydroxide and sodium silicate solutions. Results showed that workability decreased as the GGBS content increased. Compressive, splitting tensile, and flexural strengths all increased with hydration time and generally increased as the GGBS content increased up to 30% replacement of cement. The alkali-activated concrete reached strengths comparable to ordinary Portland cement concrete.
A Review On Development Of Flyash Based High Strength Geopolymer Concretecedmmantc5411
Geopolymer concrete is the latest development in the field of concrete technology and it is still
developing. Geopolymers are inorganic, stable, hard and non-inflammable binder. The application of
geopolymer binder are in fire resistance fiber composite, sealant industry, tooling aeronautics SPF aluminium,
foundry equipment’s, radioactive toxic waste, ceramic, bricks and other precast concrete. The current review is
aims to put forward the development in geopolymer concrete for the production high strength geopolymer
concrete having strength more than 90MPa. The development of high strength concrete is aimed to reduce
structural member sizes and for economical construction in case of long span bridges and tall buildings. Also
the use flyash in concrete to reduce green gas house emission into the atmosphere by reducing cement usage
This research represents an experimental study on influence of urea on concrete through various tests on urea, cement, concrete and water. Test of finesses modulus, slump test, carbonation test, pH test, urea ingression test and increase in strength with urea percentage .This study deals to overcome three major problems in the concrete namely heat of hydration, permeability, and corrosion of steel bar embedded in concrete. Urea can generally reduce the temperature of concrete both at casting phase and during the procedure of hydration. Urea does not opposite effect the durability of reinforced concrete, except where there is an accumulation of urea crystal growth. Er. Babita | Mr. Ravi Prakash Sharma | Mr. Vikram | Dr. D. K. Gupta ""Influence of Urea on Concrete"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30172.pdf
Paper Url : https://www.ijtsrd.com/engineering/civil-engineering/30172/influence-of-urea-on-concrete/er-babita
This document summarizes a study on the strength and shrinkage properties of alkali-activated slag concrete (AASC) placed in a large concrete column. Key findings include:
1) The AASC had improved workability over time compared to ordinary portland cement concrete, with minimal slump loss over 2 hours.
2) The temperature development in the AASC column was similar to a blended cement column and slower than an ordinary portland cement column, with a smaller temperature difference between the interior and exterior.
3) The compressive strength of the AASC column was identical to ordinary portland cement concrete and stronger than blended cement concrete at 28 and 91 days.
4) Embedded strain gauges
This document summarizes a study on the effect of sulphuric acid in water on the strength of blended cement concrete. Concrete cubes were produced using mixing and curing water with varying concentrations of sulphuric acid from 100-900 mg/L. The compressive strengths at 28 and 90 days were evaluated and decreased with increasing acid concentration. Regression models were developed that can predict the compressive strength based on the sulphuric acid concentration in water. The setting times of the blended cement also increased significantly with concentrations over 300 mg/L. In conclusion, higher sulphuric acid concentrations in water were found to reduce the strength of blended cement concrete.
Statistical modeling to forecast the strength of concrete using accelerated c...eSAT Journals
Abstract It is very much necessary to know the performance of the concrete mix before their actual use on site. The fact that all the required readings of concrete are only obtained after 28 days of curing which becomes a constraint when various grades of concrete are to be used in the same work. Accelerated curing of concrete is a good solution in such cases. IS 9013-1978 gives detailed description as well as guidelines to be adopted during the process of accelerated curing along with an equation to predict the 28 days strength of the concrete. An equation which predicts the achievable strength of concrete under normal curing by using the accelerated curing strength as the dependent parameter is available in the IS code. In this paper we have analyzed the reliability of the equation when additives such as fly ash are used in the mix. At the end it was found that the predicted values largely varied from the actual values obtained from the IS code. In this paper an effort is made to form a new equation by using 3 independent variables such as the fly ash content, water-cement ratio and the accelerated curing strength to obtain fairly reliable results. Key Words: Statistical modelling, Regression, Strength of concrete, Accelerated curing, fly ash
IRJET-Study on Strength and Durability Aspects of Geopolymer ConcreteIRJET Journal
This document summarizes a study on the strength and durability properties of geopolymer concrete using fly ash and ground granulated blast furnace slag (GGBS) as binders to replace cement. Various mix designs were tested with different ratios of fly ash to GGBS. The compressive strength and split tensile strength of the geopolymer concrete cubes increased with an increasing percentage of GGBS in the mix. The highest compressive strength of 66MPa was observed for a mix with a 60% fly ash and 40% GGBS ratio. Additionally, sorptivity tests found that geopolymer concrete has lower water absorption than traditional concrete, indicating better durability. The study demonstrates that geopolymer concrete
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Study on Alkali-Activated Concrete Containing High Volume GGBS with 30% Cemen...IJERA Editor
This document summarizes a study on alkali-activated concrete containing high volumes of ground granulated blast furnace slag (GGBS) as a partial replacement for cement. The study investigated the workability and mechanical properties of alkali-activated concrete mixtures containing 30% less cement replaced by GGBS. The GGBS was activated using sodium hydroxide and sodium silicate solutions. Results showed that workability decreased as the GGBS content increased. Compressive, splitting tensile, and flexural strengths all increased with hydration time and generally increased as the GGBS content increased up to 30% replacement of cement. The alkali-activated concrete reached strengths comparable to ordinary Portland cement concrete.
Effect Of Curing Temperature And Curing Hours On The Properties Of Geo-Polyme...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document presents the results of a study on the drying shrinkage of concrete made with three different cement types: ordinary Portland cement (OPC), Portland pozzolana cement (PPC), and Portland slag cement (PSC). Specimens were cured in normal water or artificial seawater for periods up to 365 days. The study found that PPC and PSC concretes experienced lower drying shrinkage compared to OPC concrete in both curing conditions. Additionally, blended cement concretes exhibited better workability than OPC concrete. The improved performance of blended cement composites is attributed to the pozzolanic reactions and filler effect of supplementary cementitious materials in PPC and PSC.
Abstract
The paper presents the studies on properties of blended concretes containing various mineral admixtuers like fly ash, silica fume, ground granulated blast furnace slag and metakaolin as partial replacement to cement. By addition of these admixtures reduces the cement content so that it can minimize the enivornment impact from the producion of cement.Various properties of blended concretes are reviewed from different research articles.
Keywords- Blended Concrete, Binary Blended, Triple Blended, Quaternary Blended Concretes, Strength Properties, Durability Properties
The document discusses research into developing more sustainable concrete materials through the use of alternative binding materials like geopolymers and reactive vitreous enamel coatings on steel fibers. Specimens were prepared by coating fibers in enamel and embedding them in fly ash or metakaolin-based geopolymer matrices. Pullout testing showed coatings improved bond strength but also weakened fibers. Push-out testing was found to better evaluate bond strengths, showing coatings increased bond strengths in fly ash matrices but decreased them in metakaolin matrices likely due to shrinkage cracking. SEM and EDX analysis provided information on microstructure and chemical composition at interfaces. Overall the research aimed to improve fiber reinforced concrete through more sustainable material selections.
An Experimental Study on Durability of Concrete Using Fly Ash & GGBS for M30 ...IJERD Editor
Concrete when subjected to severe environments its durability can significantly decline due to
degradation. Degradation of concrete structures by corrosion is a serious problem and has major economic
implications. In this study, an attempt has been made to study the durability of concrete using the mineral
admixtures like Fly Ash & Ground Granulated Blast Furnace Slag (GGBS) for M30 grade concrete.Cube
Specimens were casted and are immersed in normal water, sea water, H2SO4 of various concentrations and were
tested after 7 days, 28 days & 60 days.
Curing Methods and Their Effects on The Strength of ConcreteIJERA Editor
There are a lot of arguments on which method of curing concrete gives good strength. These different opinions results into this study, which aim at investigating the effects of different curing methods on the strength of concrete. Laboratory test was employed for this study. Normal concretes were prepared using specified mix ratio of 1:2:4 and 1:3:6. The cubes tested for compressive strength at 3, 7, 21, and 28 days of curing respectively using four curing methods namely immersion, sprinkling, polythene sheeting and sharp sand coating. Testing indicate that water immersion curing method as well as sprinkling (spraying ) methods of curing, provide better results than membrane (polythene sheeting) method of curing. While sharp sand gives least strength. The rate of drying was significant when the specimens were subjected to curing with polythene sheet method of curing. This thus hampered the hydration process and thus affected the compressive strength property of the hardened concrete. The overall findings of this study suggests that concrete should be cured by water immersion or spraying regularly to achieve a better compressive strength in concrete.
IRJET- Evaluation of Water Absorption and Sorptivity Properties of Fly Ash, G...IRJET Journal
1) The document evaluates the water absorption and sorptivity properties of fly ash and GGBS based geopolymer concrete with different volume fractions of glass fibers added.
2) Specimens were tested for water absorption at 30 minutes and 24 hours by measuring their saturated and dry masses. Addition of glass fibers decreased absorption rates compared to control geopolymer concrete.
3) Sorptivity testing involved measuring mass changes of specimens exposed to water over time. Sorptivity values, calculated from the slope of mass change vs square root of time, decreased with glass fiber addition, indicating a denser microstructure with fewer interconnected pores.
Experimental study on Self Compacting Geopolymer ConcreteIRJET Journal
This document summarizes an experimental study on self-compacting geopolymer concrete. The study investigated replacing fly ash-based geopolymer concrete with various percentages of ground granulated blast furnace slag (GGBS). Test results found that adding GGBS decreased workability but increased strength. Both oven-cured and ambient-cured concrete specimens showed increased strength with higher binder content. The study concluded that self-compacting geopolymer concrete is suitable for both curing methods when using GGBS to replace fly ash in the binder.
IRJET- Experimental Investigation of Self Compacting and Self Curing Concrete...IRJET Journal
This document presents an experimental investigation of self-compacting and self-curing concrete with different admixtures. The objective is to study the strength of concrete using a combination of self-compacting and self-curing properties. Tests were conducted on various materials used in concrete including cement, fine aggregate, coarse aggregate, water, Conplast SP430 superplasticizer, and Polyethylene Glycol 400 as a self-curing agent. Concrete mixtures were prepared with different dosages of admixtures and cured without external curing. Compressive strength tests were performed on specimen cubes to analyze the effects of self-compacting and self-curing properties on concrete strength.
The document summarizes an experimental study on the effect of salt water on the compressive strength of concrete. Concrete cubes were cast using both fresh water and salt water (35g of salts per liter of water), and cured for 7, 14, and 28 days. The compressive strength was then tested. The results showed that concrete cubes cast and cured with salt water had slightly higher compressive strengths compared to those cast and cured with fresh water at all ages. At 28 days, the compressive strengths were 39.12 MPa for fresh water cubes and 41.34 MPa for salt water cubes. The study concluded that there is no reduction and even a small increase in compressive strength when salt water is used for casting and
Workability studies on concrete with ggbs as a replacement material for cemen...iaemedu
This document discusses a study on the workability of concrete with ground granulated blast furnace slag (GGBS) as a partial replacement for cement. The workability of M20 and M25 grade concrete mixes was tested with 0-100% replacement of cement by GGBS, both with and without a superplasticizer. Various workability tests were conducted including slump testing, compaction factor testing, vee-bee consistometer testing, and flow table testing. The results showed that up to a certain percentage replacement, usually around 50-60%, the workability of the concrete increased with GGBS replacement as measured by the different tests. Above this percentage, the workability began to decrease with further GGBS
Durability Studies of Fly Ash Based Geopolymer ConcreteIJERA Editor
A detailed study on the durability of geopolymer concrete has been done. Geopolymer concrete is an
environment friendly concrete which has lower carbon footprint as compared to that of conventional concrete. In
this study, cement has been replaced by fly ash and the properties such as compressive strength, sulphur
resistance, acid resistance, water absorption, sorptivity and chloride attack have been studied. Class F fly ash has
been used and geopolymer concrete was heat cured for 24 hours under 75◦C. It was observed that use of
geopolymer in concrete not only reduces its greenhouse footprint but, also increases its strength and resistivity
to harmful acids.
This document discusses microcracking and strength development in alkali activated slag concrete (AASC) subjected to different curing regimes. The main points are:
1) AASC cured without moist curing ("exposed") exhibited higher levels of microcracking compared to AASC with moist curing ("bath" or "sealed"), as measured by surface crack detection, water sorptivity, and mercury intrusion porosimetry tests.
2) Exposed AASC also showed significantly reduced compressive strength development compared to bath or sealed cured AASC. Strength of exposed AASC was 54% and 41% lower than bath and sealed AASC at 365 days.
3) Microcracking in
STUDY ON BEHAVIOR OF ALKALI ACTIVATED FLYASH BASED GEOPOLYMER CONCRETEIAEME Publication
This document summarizes a study on the behavior of alkali-activated fly ash-based geopolymer concrete. The study investigated the effect of different activator ratios on the properties of geopolymer concrete. Specimens were prepared with activator ratios of 1:2, 1:2.5, and 1:3. Testing showed the 1:3 ratio produced the highest compressive, split tensile, and flexural strengths at all ages. Strengths increased substantially with curing time. The 1:3 ratio also provided the most economical mix. Therefore, an activator ratio of 1:3 is recommended to achieve maximum strength in fly ash-based geopolymer concrete.
This document summarizes a study on the effects of using saturated porous blast furnace slag coarse aggregate in alkali-activated slag concrete (AAS). The study found that AAS containing the porous coarse aggregate had higher compressive strength and significantly less drying shrinkage compared to AAS made with normal weight coarse aggregate. The porous aggregate provided internal curing, with water slowly releasing inside the concrete to further hydrate the paste. Under drying conditions, AAS with porous aggregate showed 40% less shrinkage and higher strengths after 1 day compared to AAS with normal aggregate.
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
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.
Influence of Non Chloride Accelerator in Cement Concreteirjes
The present experimental work explains the combined effect of a commercial non-chloride
hardening accelerator and method of curing in the strength development of concrete. Ordinary Portland
cement (OPC) was used to produce concrete mixtures. Concrete mixtures were designed as per the guidelines of
IS 10262:2009. Compressive strength of standard cube specimens (150 mm) at early and later- age, cured with
water were studied. Performance of accelerator at a given age of concrete was assessed based on the
maximum percentage increase in the compressive strength. The strength of control mix cured with water is
taken as reference. Among various types of chemical admixtures, Non Chloride Accelerator Admixture (NCA)
is chosen. The non chloride accelerator admixture is added with normal mix of the concrete in the nominal
dosage and the effects are studied. 0.8%, 1.0%, 1.2% of non chloride accelerators were mixed with various
grades of concrete such as M20& M25. The optimum level of high early development strength was analyzed.
Average efficiency of the curing compound for the given age was calculated as the ratio of average compressive
strength of concrete cured with NCA to that cured with water. The test results revealed that, the type of
curing affected the optimum performance of accelerator in concrete mixtures. Average efficiency of the curing
compound was found to be more at early- age of the concrete mixtures.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
EXPERIMENTAL STUDIES ON PROPERTIES OF GEOPOLYMER CONCRETE WITH GGBS AND FLY ASHIAEME Publication
Objective: This paper manages the quality properties of geopolymer concrete. The primary point of this anticipate is to utilize ground granulated impact heater slag and fly fiery remains set up of common Portland concrete, keeping in mind the end goal to decrease carbon dioxide emanation. Method: From this, we can look at the properties of geopolymer concrete with bond concrete. The fixings utilized as a part of this anticipate are GGBS and Fly cinder. Sodium hydroxide and sodium silicate are utilized as basic activators. The molarity of sodium hydroxide is 8M and 10M. The proportion of soluble activators is 1:2. Calcium silicate is framed when GGBS gets responded with sodium hydroxide and sodium silicate. This calcium silicate goes about as a cover for coarse total and fine total. Findings: The response is said to be exothermic since the warmth is developed when calcium silicate is framed. Henceforth, the underlying warmth is not required to begin the polymerization procedure. The fly fiery remains and GGBS are supplanted in 5 distinctive extents (100% GGBS, 75% GGBS &25% Fly cider, half GGBS &50% Fly slag, 25% GGBS&75% Fly powder,). The curing is finished by putting examples at room temperature. Application: The examples are tried at 7 years old and 28 days, the test incorporates compressive quality, split elasticity, and flexure quality to contrast the outcomes and bond concrete.
Effect of activator solution on compressive strength of flyash geopolymer ble...IJERA Editor
The influence of the composition of activator solution on the strength of fly ash geopolymer blended with slag was investigated. The research variable include % Na2O and sodium silicate under typical controlled parameters like curing profile, water content, base material and supplementary material. In this study, the monitoring response variable was compressive strength. Finding suggests that activator solution combination has a significant effect on the properties of the GP (non-blended geopolymer) and GB (geopolymer blended with 15% slag). The experiment concludes that higher percentage of Na2O gives lower strength for GB specimens but corresponding higher strength for GP specimens. Silicate modulus has similar impact on GP and GB. Both for GP and GB specimens compressive strength is increase with higher silicate modulus.
This document describes a study on the effects of different curing regimes for geopolymer concrete composites. The study involves casting concrete specimen using fly ash and GGBS activated by a sodium hydroxide and sodium silicate solution. The specimen will be cured using different temperature curing regimes including ambient temperature curing and external exposure curing. The mechanical properties of the specimens from the different curing regimes will be tested and compared to a control specimen cured at 60°C for 24 hours. Literature on geopolymer concrete and curing was reviewed to inform the methodology. Materials to be used include fly ash, GGBS, sodium hydroxide pellets, and sodium silicate solution. Properties of the materials will
Effect Of Curing Temperature And Curing Hours On The Properties Of Geo-Polyme...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document presents the results of a study on the drying shrinkage of concrete made with three different cement types: ordinary Portland cement (OPC), Portland pozzolana cement (PPC), and Portland slag cement (PSC). Specimens were cured in normal water or artificial seawater for periods up to 365 days. The study found that PPC and PSC concretes experienced lower drying shrinkage compared to OPC concrete in both curing conditions. Additionally, blended cement concretes exhibited better workability than OPC concrete. The improved performance of blended cement composites is attributed to the pozzolanic reactions and filler effect of supplementary cementitious materials in PPC and PSC.
Abstract
The paper presents the studies on properties of blended concretes containing various mineral admixtuers like fly ash, silica fume, ground granulated blast furnace slag and metakaolin as partial replacement to cement. By addition of these admixtures reduces the cement content so that it can minimize the enivornment impact from the producion of cement.Various properties of blended concretes are reviewed from different research articles.
Keywords- Blended Concrete, Binary Blended, Triple Blended, Quaternary Blended Concretes, Strength Properties, Durability Properties
The document discusses research into developing more sustainable concrete materials through the use of alternative binding materials like geopolymers and reactive vitreous enamel coatings on steel fibers. Specimens were prepared by coating fibers in enamel and embedding them in fly ash or metakaolin-based geopolymer matrices. Pullout testing showed coatings improved bond strength but also weakened fibers. Push-out testing was found to better evaluate bond strengths, showing coatings increased bond strengths in fly ash matrices but decreased them in metakaolin matrices likely due to shrinkage cracking. SEM and EDX analysis provided information on microstructure and chemical composition at interfaces. Overall the research aimed to improve fiber reinforced concrete through more sustainable material selections.
An Experimental Study on Durability of Concrete Using Fly Ash & GGBS for M30 ...IJERD Editor
Concrete when subjected to severe environments its durability can significantly decline due to
degradation. Degradation of concrete structures by corrosion is a serious problem and has major economic
implications. In this study, an attempt has been made to study the durability of concrete using the mineral
admixtures like Fly Ash & Ground Granulated Blast Furnace Slag (GGBS) for M30 grade concrete.Cube
Specimens were casted and are immersed in normal water, sea water, H2SO4 of various concentrations and were
tested after 7 days, 28 days & 60 days.
Curing Methods and Their Effects on The Strength of ConcreteIJERA Editor
There are a lot of arguments on which method of curing concrete gives good strength. These different opinions results into this study, which aim at investigating the effects of different curing methods on the strength of concrete. Laboratory test was employed for this study. Normal concretes were prepared using specified mix ratio of 1:2:4 and 1:3:6. The cubes tested for compressive strength at 3, 7, 21, and 28 days of curing respectively using four curing methods namely immersion, sprinkling, polythene sheeting and sharp sand coating. Testing indicate that water immersion curing method as well as sprinkling (spraying ) methods of curing, provide better results than membrane (polythene sheeting) method of curing. While sharp sand gives least strength. The rate of drying was significant when the specimens were subjected to curing with polythene sheet method of curing. This thus hampered the hydration process and thus affected the compressive strength property of the hardened concrete. The overall findings of this study suggests that concrete should be cured by water immersion or spraying regularly to achieve a better compressive strength in concrete.
IRJET- Evaluation of Water Absorption and Sorptivity Properties of Fly Ash, G...IRJET Journal
1) The document evaluates the water absorption and sorptivity properties of fly ash and GGBS based geopolymer concrete with different volume fractions of glass fibers added.
2) Specimens were tested for water absorption at 30 minutes and 24 hours by measuring their saturated and dry masses. Addition of glass fibers decreased absorption rates compared to control geopolymer concrete.
3) Sorptivity testing involved measuring mass changes of specimens exposed to water over time. Sorptivity values, calculated from the slope of mass change vs square root of time, decreased with glass fiber addition, indicating a denser microstructure with fewer interconnected pores.
Experimental study on Self Compacting Geopolymer ConcreteIRJET Journal
This document summarizes an experimental study on self-compacting geopolymer concrete. The study investigated replacing fly ash-based geopolymer concrete with various percentages of ground granulated blast furnace slag (GGBS). Test results found that adding GGBS decreased workability but increased strength. Both oven-cured and ambient-cured concrete specimens showed increased strength with higher binder content. The study concluded that self-compacting geopolymer concrete is suitable for both curing methods when using GGBS to replace fly ash in the binder.
IRJET- Experimental Investigation of Self Compacting and Self Curing Concrete...IRJET Journal
This document presents an experimental investigation of self-compacting and self-curing concrete with different admixtures. The objective is to study the strength of concrete using a combination of self-compacting and self-curing properties. Tests were conducted on various materials used in concrete including cement, fine aggregate, coarse aggregate, water, Conplast SP430 superplasticizer, and Polyethylene Glycol 400 as a self-curing agent. Concrete mixtures were prepared with different dosages of admixtures and cured without external curing. Compressive strength tests were performed on specimen cubes to analyze the effects of self-compacting and self-curing properties on concrete strength.
The document summarizes an experimental study on the effect of salt water on the compressive strength of concrete. Concrete cubes were cast using both fresh water and salt water (35g of salts per liter of water), and cured for 7, 14, and 28 days. The compressive strength was then tested. The results showed that concrete cubes cast and cured with salt water had slightly higher compressive strengths compared to those cast and cured with fresh water at all ages. At 28 days, the compressive strengths were 39.12 MPa for fresh water cubes and 41.34 MPa for salt water cubes. The study concluded that there is no reduction and even a small increase in compressive strength when salt water is used for casting and
Workability studies on concrete with ggbs as a replacement material for cemen...iaemedu
This document discusses a study on the workability of concrete with ground granulated blast furnace slag (GGBS) as a partial replacement for cement. The workability of M20 and M25 grade concrete mixes was tested with 0-100% replacement of cement by GGBS, both with and without a superplasticizer. Various workability tests were conducted including slump testing, compaction factor testing, vee-bee consistometer testing, and flow table testing. The results showed that up to a certain percentage replacement, usually around 50-60%, the workability of the concrete increased with GGBS replacement as measured by the different tests. Above this percentage, the workability began to decrease with further GGBS
Durability Studies of Fly Ash Based Geopolymer ConcreteIJERA Editor
A detailed study on the durability of geopolymer concrete has been done. Geopolymer concrete is an
environment friendly concrete which has lower carbon footprint as compared to that of conventional concrete. In
this study, cement has been replaced by fly ash and the properties such as compressive strength, sulphur
resistance, acid resistance, water absorption, sorptivity and chloride attack have been studied. Class F fly ash has
been used and geopolymer concrete was heat cured for 24 hours under 75◦C. It was observed that use of
geopolymer in concrete not only reduces its greenhouse footprint but, also increases its strength and resistivity
to harmful acids.
This document discusses microcracking and strength development in alkali activated slag concrete (AASC) subjected to different curing regimes. The main points are:
1) AASC cured without moist curing ("exposed") exhibited higher levels of microcracking compared to AASC with moist curing ("bath" or "sealed"), as measured by surface crack detection, water sorptivity, and mercury intrusion porosimetry tests.
2) Exposed AASC also showed significantly reduced compressive strength development compared to bath or sealed cured AASC. Strength of exposed AASC was 54% and 41% lower than bath and sealed AASC at 365 days.
3) Microcracking in
STUDY ON BEHAVIOR OF ALKALI ACTIVATED FLYASH BASED GEOPOLYMER CONCRETEIAEME Publication
This document summarizes a study on the behavior of alkali-activated fly ash-based geopolymer concrete. The study investigated the effect of different activator ratios on the properties of geopolymer concrete. Specimens were prepared with activator ratios of 1:2, 1:2.5, and 1:3. Testing showed the 1:3 ratio produced the highest compressive, split tensile, and flexural strengths at all ages. Strengths increased substantially with curing time. The 1:3 ratio also provided the most economical mix. Therefore, an activator ratio of 1:3 is recommended to achieve maximum strength in fly ash-based geopolymer concrete.
This document summarizes a study on the effects of using saturated porous blast furnace slag coarse aggregate in alkali-activated slag concrete (AAS). The study found that AAS containing the porous coarse aggregate had higher compressive strength and significantly less drying shrinkage compared to AAS made with normal weight coarse aggregate. The porous aggregate provided internal curing, with water slowly releasing inside the concrete to further hydrate the paste. Under drying conditions, AAS with porous aggregate showed 40% less shrinkage and higher strengths after 1 day compared to AAS with normal aggregate.
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
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.
Influence of Non Chloride Accelerator in Cement Concreteirjes
The present experimental work explains the combined effect of a commercial non-chloride
hardening accelerator and method of curing in the strength development of concrete. Ordinary Portland
cement (OPC) was used to produce concrete mixtures. Concrete mixtures were designed as per the guidelines of
IS 10262:2009. Compressive strength of standard cube specimens (150 mm) at early and later- age, cured with
water were studied. Performance of accelerator at a given age of concrete was assessed based on the
maximum percentage increase in the compressive strength. The strength of control mix cured with water is
taken as reference. Among various types of chemical admixtures, Non Chloride Accelerator Admixture (NCA)
is chosen. The non chloride accelerator admixture is added with normal mix of the concrete in the nominal
dosage and the effects are studied. 0.8%, 1.0%, 1.2% of non chloride accelerators were mixed with various
grades of concrete such as M20& M25. The optimum level of high early development strength was analyzed.
Average efficiency of the curing compound for the given age was calculated as the ratio of average compressive
strength of concrete cured with NCA to that cured with water. The test results revealed that, the type of
curing affected the optimum performance of accelerator in concrete mixtures. Average efficiency of the curing
compound was found to be more at early- age of the concrete mixtures.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
EXPERIMENTAL STUDIES ON PROPERTIES OF GEOPOLYMER CONCRETE WITH GGBS AND FLY ASHIAEME Publication
Objective: This paper manages the quality properties of geopolymer concrete. The primary point of this anticipate is to utilize ground granulated impact heater slag and fly fiery remains set up of common Portland concrete, keeping in mind the end goal to decrease carbon dioxide emanation. Method: From this, we can look at the properties of geopolymer concrete with bond concrete. The fixings utilized as a part of this anticipate are GGBS and Fly cinder. Sodium hydroxide and sodium silicate are utilized as basic activators. The molarity of sodium hydroxide is 8M and 10M. The proportion of soluble activators is 1:2. Calcium silicate is framed when GGBS gets responded with sodium hydroxide and sodium silicate. This calcium silicate goes about as a cover for coarse total and fine total. Findings: The response is said to be exothermic since the warmth is developed when calcium silicate is framed. Henceforth, the underlying warmth is not required to begin the polymerization procedure. The fly fiery remains and GGBS are supplanted in 5 distinctive extents (100% GGBS, 75% GGBS &25% Fly cider, half GGBS &50% Fly slag, 25% GGBS&75% Fly powder,). The curing is finished by putting examples at room temperature. Application: The examples are tried at 7 years old and 28 days, the test incorporates compressive quality, split elasticity, and flexure quality to contrast the outcomes and bond concrete.
Effect of activator solution on compressive strength of flyash geopolymer ble...IJERA Editor
The influence of the composition of activator solution on the strength of fly ash geopolymer blended with slag was investigated. The research variable include % Na2O and sodium silicate under typical controlled parameters like curing profile, water content, base material and supplementary material. In this study, the monitoring response variable was compressive strength. Finding suggests that activator solution combination has a significant effect on the properties of the GP (non-blended geopolymer) and GB (geopolymer blended with 15% slag). The experiment concludes that higher percentage of Na2O gives lower strength for GB specimens but corresponding higher strength for GP specimens. Silicate modulus has similar impact on GP and GB. Both for GP and GB specimens compressive strength is increase with higher silicate modulus.
This document describes a study on the effects of different curing regimes for geopolymer concrete composites. The study involves casting concrete specimen using fly ash and GGBS activated by a sodium hydroxide and sodium silicate solution. The specimen will be cured using different temperature curing regimes including ambient temperature curing and external exposure curing. The mechanical properties of the specimens from the different curing regimes will be tested and compared to a control specimen cured at 60°C for 24 hours. Literature on geopolymer concrete and curing was reviewed to inform the methodology. Materials to be used include fly ash, GGBS, sodium hydroxide pellets, and sodium silicate solution. Properties of the materials will
COMPARATIVE STUDY OF COMPRESSIVE STRENGTH AND DURABILITY PROPERTIES ON GEOPOL...Journal For Research
This document summarizes a study that evaluated the compressive strength and durability properties of geopolymer concrete made with ultra-fine ground granulated blast furnace slag (GGBS). Several mix designs were tested with different ratios of GGBS, fly ash, and ultra-fine GGBS. The mix with 20% replacement of ultra-fine GGBS achieved the highest compressive strength of 91.1 MPa. Durability tests also showed improved results for mixes with higher ultra-fine GGBS content, as it reduced voids in the concrete. The study demonstrated that geopolymer concrete made with ultra-fine GGBS can provide high strength and durability suitable for construction applications.
Performance of alkaline solutions on grades of geopolymer concreteeSAT 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
Performance of alkaline solutions on grades of geopolymer concreteeSAT Journals
Abstract Geopolymer is a class of aluminosilicate binding materials synthesized by thermal activation of solid aluminosilicate base materials such as fly ash, metakaolin, GGBS etc., with an alkali metal hydroxide and silicate solution. The geopolymer was activated with sodium hydroxide, sodium silicate and heat. This paper presents the experimental investigation done on the variation of alkaline solution on mechanical properties of geopolymer concrete. The grades chosen for the investigation were M-30, M-40, M-50 and M-60, the mixes were designed for 8 molarity. The alkaline solution used for present study was the combination of sodium silicate and sodium hydroxide solution with the varying ratio of 2, 2.50, 3 and 3.50. The test specimens were 150x150x150 mm cubes and 100x200 mm cylinders heat-cured at 60°C in an oven. The results revealed that the workable flow of geopolymer concrete was in the range of 85 to 145 and was dependent on the ratio by mass of sodium silicate and sodium hydroxide solution. The freshly prepared geopolymer mixes were cohesive and their workability increased with the increase in the ratio of alkaline solution. The strength of geopolymer concrete can be improved by decreasing the water/binding and aggregate/binding ratios. The curing period improves the polymerization process resulting in higher compressive strength. The geopolymer concrete do not have any Portland cement, they can be considered as less energy interactive. It utilizes the industrial wastes such as fly ash for producing the binding system in concrete. The obtained compressive strength and split tensile strength were in the range of 20.64 – 60 N/mm2 and 3 – 4.9 N/mm2. The optimum dosage for alkaline solution can be considered as 2.5, because for this ratio the GPC specimens of any grade produced maximum strength in compression and tension. Keywords: geopolymer concrete, fly ash, molarity, sodium silicate, sodium hydroxide
This document summarizes a research paper that studied the abrasion resistance of geopolymer concrete at varying temperatures. The paper prepared geopolymer concrete samples using fly ash as the source material and an alkaline solution of sodium hydroxide and sodium silicate. Samples were cured at 25°C, 60°C, and 80°C and tested for abrasion resistance at 5-25 minutes using a tile abrasion testing machine. Results showed that abrasion resistance increased with higher curing temperature, with samples cured at 80°C showing the highest resistance. The paper concluded that geopolymer concrete has good abrasion resistance properties and further research is needed on mixtures with higher alkaline liquid ratios.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
CHARACTERIZATION & DURABILITY PROPERTIES OF ULTRAFINE FLY ASH BASED GEOPOLYME...Journal For Research
Huge scale generation of cement is creating environmental issue on one hand and depletion of natural resources on the other hand. This danger to nature has prompted research being made of industrial byproducts as supplementary cementetious materials in making concrete for more green and durable. Fly ash and silica fume both are pozzolanic materials which have been broadly utilized for improving the properties like strength and durability in concrete. Silica fume demonstrates the greater pozzolanic activity then fly ash because of its finer particle size distribution, the pozzolanic activity of fly ash also can be enhanced by decreasing the particle size distribution. Geopolymer is a class of aluminosilicate binding materials integrated by thermal action of solid aluminosilicate based materials such as metakoaline, GGBFS, fly ash. Geopolymer get activated with the alkaline solution and heat. Sodium hydroxide and sodium silicate were utilized as an alkaline solution with a steady ratio of 2.5 and the mix is designed for molarity 10 for the work carried out. In the present study, an attempt has been made to explore the geopolymer concrete by utilizing ultrafine fly ash (UFFA) produced by air classification and processed GGBFS with varied proportions. Discusses on the properties of geopolymer concrete has also been mentioned. Compressive strength and durability tests like Permeability, Abrasion, Sorptivity, Acid and sulphate attack, Drying shrinkage were conducted. In this work geopolymer concrete was prepared with varying proportions of GGBS and UFFA in the ratio of 92.5:7.5 and 88:12 and 80:20. The maximum strength was achieved for the ratio 92.5:7.5. The obtained compressive strength is in the range of 36.5MPa to 91.6MPa from 1st day to 28th day of hot curing.
EFFECTS OF ALKALI ACTIVATORS ON STRENGTH.pptxNadeemAfridi2
1. The document summarizes research on the effects of alkali activators on the strength characteristics of geopolymer concrete (GPC). GPC is an eco-friendly alternative to ordinary Portland cement concrete that uses industrial byproducts like fly ash activated by alkaline solutions instead of cement.
2. Studies tested the compressive, tensile, and flexural strengths of GPC mixes with different molarities and ratios of alkaline activators, curing methods, and additives. The optimal mix was found to be a molarity of 14M, binder ratio of 2.5, and ambient curing, achieving strengths of 46.43 MPa in compression and 4.4 MPa in tension.
STRENGTH AND DURABILITY STUDY OF GROUND GRANULATED BLAST FURNACE SLAG BASED G...Shoaib Wani
This document studies the strength and durability of ground granulated blast furnace slag (GGBS) based geopolymer concrete. The study aims to determine the compressive strength and durability parameters of GGBS concrete with varying molar concentrations of sodium hydroxide (NaOH) solutions. The results show that compressive strength increases with higher NaOH concentration from 5M to 8M. Rapid chloride permeability and water absorption tests also indicate improved durability. In conclusion, GGBS concrete provides higher strength than conventional concrete and has potential as a more sustainable alternative if setting time issues can be addressed.
This document summarizes a study on the strength, economic, and sustainability characteristics of geopolymer concrete made with coal ash and ground granulated blast furnace slag (GGBS). The study found that:
1) Fly ash-based geopolymer concrete achieved a compressive strength of 68MPa, while bottom ash-based concrete only achieved 32MPa due to the larger particle size of bottom ash.
2) Curing geopolymer concrete at ambient temperature resulted in comparable strengths as curing at elevated temperatures.
3) An economic analysis found that geopolymer concrete can be produced at a comparable cost to ordinary Portland cement concrete, while offering significant reductions in carbon dioxide emissions.
DURABILITY STUDIES OF GGBS AND METAKAOLIN BASED GEOPOLYMER CONCRETE Ijciet 08...IAEME Publication
The objective of this research work was to produce a carbon dioxide emission free cementious
material. The geopolymer concrete is such a vital and promising one. In this study, geopolymer is
prepared from ‘Ground Granulated Blast Furnace Slag’ (GGBS) a powder from grinding the byproduct
of slag waste from blast furnace of steel plants and metakaolin from industry. The Alkaline
liquids used in this study for the polymerization process are the solutions of sodium hydroxide
(NaoH) and sodium silicate (Na2Sio3).A 8 Molarity and 10 Molarity solutions was taken to prepare
the mix. The cube compressive strength was calculated for different mixes. The cube specimens are
taken of size 150 mm x 150 mm x 150 mm. Ambient curing of concrete at room temperature was
adopted. In total 180 cubes were casted for their compressive strength at age of 28 days
respectively. The test data indicate that on exposure to 5% Sodium Sulphate, Sulphuric Acid and
Sodium Chloride, the losses in weight, and strength of geopolymer concrete (GPC) are
significantly much less than those for cement concrete. Thus the geopolymer concrete is considered
to be an environmentally pollution free construction material.
Mechanical Properties and Flexural Performance of Geopolymer ConcreteIRJET Journal
This document presents the results of an experimental study on the mechanical properties and flexural performance of geopolymer concrete. Fly ash was used as the sole binder to replace cement. Different mix proportions of geopolymer concrete with compressive strengths ranging from 20 MPa to 35 MPa were tested. The specimens were heat cured at 60°C for 24 hours. Testing showed that the compressive strength and flexural strength of the geopolymer concrete samples increased as the fly ash content increased. An empirical formula is derived from the test results to predict the strengths of fly ash-based geopolymer concrete.
Enhanced fluidized bed methanation over a Ni Al2O3 catalyst for production of...Pengcheng Li
This document summarizes a study that investigated the fluidization behavior and CO methanation performance of a Ni/Al2O3 catalyst in a fluidized bed reactor for producing synthetic natural gas. The researchers found that the pure Ni/Al2O3 catalyst failed to properly fluidize on its own due to particle sizes between 10 and 100 μm, but fluidization was improved by adding larger Al2O3 particles. Methanation performance in the fluidized bed reactor increased substantially with the Al2O3 addition. Temperature was found to control the methanation reaction mechanism, with surface reactions dominating at lower temperatures and external diffusion controlling at higher temperatures. Stability tests showed the fluidized bed reactor had higher CO conversion, methane selectivity
Study on Strength of Fly Ash Based Geopolymer Concrete Under Heat Curingijsrd.com
fly ash is a noncombustible material obtained from the various thermal power plants. Since fly ash is available in large scale, it is disposed of in rivers and landfills and ponds by thermal industries which are posing danger to environment. Due to high pozzolanic activity of fly ash, efforts are being made to use it as a cement replacement material. GeoPolymer concrete makes 100 percent utilization of fly ash in concrete along with alkaline solutions, as a binder. The cube specimens and beams are casted for 2% and 4% super plasticizers and alkaline to fly ash ratio of 0.35. The compressive strength of cubes is compared to that of conventional cubes at 7, 14 and 28 days .it is observed that GeoPolymer concrete is economical as compared to normal concrete from compressive strength point of view.
[12302945 - Archives of Civil Engineering] Some Durability Aspects of Ambient...SaravanaKumar686911
The document examines the durability of ambient cured bottom ash geopolymer concrete (BA GPC), specifically its resistance to accelerated corrosion, sorptivity, and water absorption. Testing found that BA GPC developed a stronger protective layer against chloride ion diffusion, providing better corrosion protection than conventional concrete. The initial and final rates of water absorption of BA GPC were about half that of conventional concrete. BA GPC also achieved higher compressive strengths than conventional concrete under ambient curing conditions.
The document discusses geopolymer concrete as an eco-friendly construction material. It summarizes that geopolymer concrete gains strength within 24 hours of casting without water curing at ambient temperatures. The maximum compressive strength of 80.5 MPa was achieved for a mix of 60% fly ash and 40% GGBS. Adding GGBS improved strength and eliminated the need for heat curing seen in conventional geopolymer concrete. The splitting tensile and flexural strengths were also highest for the 60% fly ash and 40% GGBS mix.
Optimization of temperature imposed on activator before mixinginventionjournals
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.
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
GraphRAG for life science domain, where you retriever information from biomedical knowledge graphs using LLMs to increase the accuracy and performance of generated answers
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
UiPath Test Automation using UiPath Test Suite series, part 5DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
Speaker:
Lyndsey Byblow, Test Suite Sales Engineer @ UiPath, Inc.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Threats to mobile devices are more prevalent and increasing in scope and complexity. Users of mobile devices desire to take full advantage of the features
available on those devices, but many of the features provide convenience and capability but sacrifice security. This best practices guide outlines steps the users can take to better protect personal devices and information.
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
1. International Journal of Engineering Science Invention
ISSN (Online): 2319 – 6734, ISSN (Print): 2319 – 6726
www.ijesi.org Volume 2 Issue 2 ǁ February. 2013 ǁ PP.24-31
www.ijesi.org 24 | P a g e
Effect of Curing Conditions on the Compressive Strength and
Microstructure of Alkali-activated GGBS paste
Mohd. Nadeem Qureshi1
and Somnath Ghosh2
1
Research scholar, Department of Civil Engineering, Jadavpur University, Kolkata, India
Senior Lecturer, Government Polytechnic, Khamgaon, Maharashtra, India
2
Professor of Civil Engineering, Jadavpur University, Kolkata, India
ABSTRACT: This paper presents the effect of curing method on the strength development of alkali- activated
blast furnace slag paste. In this study, alkali activation was done using a combination of potassium hydroxide
and sodium silicate. The test parameters include the curing methods (water curing at 270
C, heat curing at 500
C
and controlled curing with relative humidity 50%, 70% and 90 % at 270
C), alkali content with 6.41 %, 8.41 %,
10.41% and 12.41 % of the mass of GGBS. The compressive strength results showed that there is an increase in
compressive strength with the increase in age of water curing and controlled curing specimens. A comparison
of hot cured specimens, the increase in compressive strength with age was less. Further heat curing has shown
to adversely affect compressive strength and to create internal micro cracking as well as surface cracks. The
higher compressive strengths were obtained from water cured specimens.
Keywords: Alkali content, blast furnace slag, compressive strength, curing conditions, microstructure,
scanning electron microscopy (SEM).
I. INTRODUCTION
The production of concrete is used by some economists as a measure of a country‟s economic strength.
Some countries already have a tax on carbon dioxide generation. Portland cement production has been already
second only to automobile as the major generator of CO2 greenhouse gas worldwide concrete production. For
every ton of cement produced generates nearly one tone of carbon dioxide. Among the greenhouse gases, CO2
contributes about 65% of global warming. Hence, to preserve the environment, we are in need of new
sustainable and environmentally friendly composites to replace conventional Portland cement. Ground
granulated blast furnace slag is a by- product from manufacturing of iron, is a molten material which appears
above the pig iron at the bottom of the blast furnace. The main component of slag, melilite is a solid solution of
(2CaO.Al2O3.SiO2) (2CaO.MgO.2SiO2), consisting 40% by weight of CaO. The production of 1 ton of iron
results in the by-product of 0.6 tons of iron slag and generates 0.19 tons of chemical- CO2 [1].
The term „Curing‟ stands for procedures devoted to hydration reaction of GGBS, consisting of control
of time, temperature, and humidity conditions. The properties of alkali activated GGBS are dependent on the
hydration and cement and time. The strength development of alkali activated slag cement concrete cured in
water bath, sealed and exposed to air conditions was studied earlier [2]. They have reported that when the
concrete is cured in water, compressive strength of concrete keeps increasing until the end of the testing period
of 365 days. However, if the specimens are cured in sealed conditions, the strength stopped increasing at about
90 days and the strength of the exposed specimens was found to be 54% and 41% less than bath and sealed
specimen strengths, respectively, at 365 days. The early age strength development (up to 28 days) of GGBS
blended concrete had found to be increasing with curing temperature, but the effect on later strength is very less
[3-5]. It was found that the effects of curing method for strength development are found only after the age of 7
days [5]. For improved durability room temperature curing is the best, but steam curing is preferable to
autoclaving curing, if rapid strength development is required [6]. Some studies suggested internal curing is an
effective method for improving performance of low W/C – low permeability concrete because they require
additional water to hydrate the cementitious materials [7]. Curing conditions had a significant effect on the
mechanical behavior in the hardened state of alkali activated slag paste compared to ordinary Portland cement
[8]. In comparing lab-cured cylinders to in-situ strength, it is commonly known that in-situ strength is lower
than strength determined from lab-cured cylinders under standard conditions. A factor of 0.85 is typically
assumed, although more recent work indicates the factor may be as low as 0.7 [9]. The pore size distribution is
strongly influenced by the curing temperature; higher temperature increases the volume of mesopores [10]. If
the potential of concrete with regards to strength and durability is to be fully utilized, it is most essential to be
cured adequately. As reported by researchers [11], the higher strengths could be obtained using lower binder
contents for cement and cement-slag mortars provided the specimens were cured in water. It was reported that
the increase in level of cement and slag makes the mortars more sensitive to air curing conditions. The curing
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becomes even more important if the concrete contains supplementary cement materials such as fly ash or ground
granulated blast-furnace slag or silica fume, and is subjected to hot and dry environments immediately after
casting [12]. The fineness of GGBS also plays a significant role in developing the compressive strength of
Alkali-activated GGBS paste [13].
To obtain the required durability, strength and high performance during the life cycle of the structure,
curing is crucial. Many previous researchers studied the behavior of particular slag at either room temperature or
at elevated temperature, but very few studies compare in- depth the activation of GGBS paste with different
curing conditions. This paper emphasizes the effect of curing method on the compressive strength development
of alkali activated blast furnace slag paste.
Table 1: Compressive strength and workability of AABFS paste with different curing conditions
(% of mass added with respect to the total mass of slag)
S.No.
%
(K2O +
Na2O)
% SiO2
Mix ID
Compressive Strength (MPa)
3 d 7d 28 d
1 6.41 8 WC 17.5 29.50 41.5
2 6.41 8 OC50
@50
deg C
16.92 18.2 21.13
3 6.41 8 RH50 14.5 21.9 27
4 6.41 8 RH70 15 23.5 35.1
5 6.41 8 RH90 16.5 28.53 40.5
6 8.41 8 WC 25.5 36.3 47.4
7 8.41 8 OC50
@50
deg C
25.88 27.5 32.6
8 8.41 8 RH50 18.95 26.5 33.5
9 8.41 8 RH70 22.6 32.03 39.3
10 8.41 8 RH90 24.8 36.69 44.1
11 10.41 8 WC 29.50 38.30 50.2
12 10.41 8 OC50
@50
deg C
30.8 32 39.12
13 10.41 8 RH50 22.95 33.55 43.33
14 10.41 8 RH70 24.5 37.4 46.5
15 10.41 8 RH90 29.5 39.2 47.25
16 12.41 8 WC 23.4 35.2 44.7
17 12.41 8 OC50
@50
deg C
26.68 28.4 34.15
18 12.41 8 RH50 20.38 28.6 38.11
19 12.41 8 RH70 22.9 33.43 42.4
20 12.41 8 RH90 24.5 35.4 44.4
II. EXPERIMENTAL DETAILS
2.1 Materials
In the present study, ground granulated blast furnace slag (GGBS) was used as a source material for the
synthesis of alkali activated blast furnace slag paste (AAGGBS). GGBS was obtained from the Tata Metaliks
Ltd. Kharagpur, India. The slag obtained was ground to fineness less than 45 microns. The chemical
composition was determined by X-Ray fluorescence spectrometry (XRF) analysis and in terms of the main
oxides was (in weight %) SiO2 (32.50), CaO (33.50), Al2O3 (18.50), MgO (8.0), Fe2O3 (0.40), S (0.5) and MnO
(0.55).
For the alkaline activator, a combination of potassium hydroxide and sodium silicate solution was used.
Potassium hydroxide in pellet forms with 84% purity, supplied by Merck India Ltd. (K2O =83. 93% and 16.07%
water) and sodium silicate solution (Na2O = 8%, SiO2 = 26.5% and 65.50% water) with silicate modulus ~3. 3
and bulk density of 1410 kg/m3
was supplied by Loba Chemie Ltd. India, were used to adjust the desired
composition of alkali activated GGBS paste. The activator solution was prepared at least one day prior to its use.
Potable water was used in all mixes for casting and in curing of the specimens.
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2.2 Design of Mix Proportion
In this experimental work, the alkali activated GGBS paste was prepared according to the composition
shown in Table 1. The compositional change in GGBS mix was obtained by adjusting the quantity of potassium
hydroxide (KOH), sodium silicate solution and water.
2.3 Mixing and casting of test specimens
Mixing procedure was carried out in two stages. Initially, GGBS (in dry condition) were hand mixed in
a container for about 5 minutes along with the desired proportion of alkaline solution and then the mixture is
transferred in Hobart mixer and mixed for another five minutes to get homogeneous paste. The fresh mix was
placed in steel moulds of size 50 mm x 50 mm with two layers of fresh paste and each layer is compacted using
a rod of 16 mm diameter. Then the moulds with fresh mix were vibrated for two minutes on vibrating table to
remove any entrapped air. The workability of fresh paste was assessed using mini flow table test as per ASTM
C 1437-07 [14] with a modification; the table was raised and dropped 15 times in about 15 seconds. The mini
flow table apparatus was used as per ASTM C 230/C 230M-08 [15]. The workability of the mix was determined
by measuring the diameter of paste flow on a flow table in two perpendicular directions after 15 drops in 15
seconds and the average value is considered as a flow diameter. The percentage increase in flow diameter with
respect to the initial diameter of mould is considered as flow value. The flow percentage was found to be 41 %,
55 %, 65 % and 75 % for 6.41 %, 8.41 %, 10.41 % and 12.41 % alkali content respectively [16].
(a)
(b)
(c)
(d)
Figure 1: The effect of various curing conditions on compressive strength for different alkali content
(K2O+ Na2O) (a) 6.41 % (b) 8.41 % (c) 10.41 % and (d) 12.41 %.
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2.4 Curing conditions of test specimens
The test specimens were cured in water curing , controlled curing with 50 % , 70 % and 90 % relative
humidity and dry oven curing at 500
C designated as „WC‟, „RH50‟, „RH70‟, „RH90‟ and „OC50‟ respectively.
For water curing, the specimens after casting were left at room temperature for 24 hours, then de-molded and
kept in water in fully immersed condition at room temperature until testing was done. For controlled curing, the
specimens after casting were left at room temperature for 24 hours, then de-molded and kept in humidity
chamber at 50 % RH, 70 % RH and 90 % RH. For heat curing, the specimens after casting with two hour delay
were kept in the oven at 500
C for 24 hours. The test specimens then removed from the molds and left to air dry
in the room temperature conditions until tested for direct compression at a specified age.
2.5 Test Methods
The alkali-activated GGBS (AAGGBS) paste specimens (50mm x 50mm x 50mm) were tested for
compressive strength using 20 ton capacity digital compressive testing machine with a loading rate of 20
MPa/min. The compressive strength tests were conducted at the age of 3, 7 and 28 days. Three specimens of
each series at each age were crushed in a digital compression testing machine in accordance with ASTM C-109-
02 [17] and the average strength of three specimens is reported as the compressive strength.
(a)
(b)
(c)
(d)
Figure 2: Variation of compressive strength with age for various curing conditions for different alkali
content (K2O+ Na2O) (a) 6.41 % (b) 8.41 % (c) 10.41 % and (d) 12.41 %.
0
10
20
30
40
50
60
3 7 28
Compressivestrength
(MPa)
Age (days)
10.41 % (K2O+Na2O) RH50
RH70
RH90
OC50
WC
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III. RESULTS AND DISCUSSION
3.1 Influence of curing conditions on compressive strength
Table 1 presents synthesis parameters and the compressive strength of AAGGBS paste specimens
produced at alkali content ( K2O +Na2O) varied from 6.41 % to 12.41 %. Water to slag ratio and silica content
was kept constant to 0.32 and 8 % respectively. Variations of compressive strength of the specimens cured in
water (WC) at room temperature (270
C), controlled curing with 50 % (RH50), 70 % (RH70) and 90 % (RH90)
relative humidity and dry oven curing at 500
C (OC50) are shown in Fig. 1 and 2. It was observed that the
compressive strength increases with increase in alkali content from 6.41 % to 10.41 % for all types of curing
methods and reaches maximum 50.20 MPa for alkali content of 10.41 % for water cured specimens. The
compressive strength results showed that, there was an increase in strength with increase in age for all types of
curing methods. The percentage increase in 28 days strength over 3 days strength was found to be 67.55 %,
27.01 %, 88.88 %, 89.79 % and 60.16 % for WC, OC50, RH50, RH70 and RH90 respectively for the optimum
8 % (K2O +Na2O). Comparisons of hot cured samples the increase in compressive strength with age was less.
The hydration of cement can take place only when the vapor pressure in the capillaries is sufficiently
high, about 0.8 of saturation pressure [18,19]. Therefore, early drying of concrete may stop the cement
hydration before the pores are blocked by hydration products and thus a more continuous pore structure
may be formed. The comparison of compressive strength of various curing methods was given in Table 1. The
results revealed that the 28 days strength of water cured specimens were 31.49 %, 18.71 %, 10.62 %, and 8.86
% higher than that of OC50, RH50, RH70 and RH90 respectively for 10.41 % alkali content.
3.2 Influence of alkali content on compressive strength
The relationship between alkali content and compressive strength is presented in Fig. 3.The increase in
compressive strength was observed with increase in alkali content until 10.41 % alkali content. Further increase
in alkali content reduces the compressive strength. This trend was observed for all types of curing method. This
may be due to excess K+
ions in the framework, the slag grains might not completely participated in the
reaction process forming C-S-H gel and the degree of reaction of the system might remain moderate. In the
present study, the optimum alkali content was observed to be 10.41 % with a SiO2/ (K2O+Na2O) ratio of 0.76
for all types of curing methods. The optimum silicate modulus phenomenon to the formation of “primary C-S-
H” and /or polymerization of silicate anions in the water glass, which promotes the hydration of slag and the
formation of less porous structure [20]. The alkali metal cations in the original materials or added alkali metal
hydroxides are considered important due to their catalytic role.
3.3 A microstructure study by scanning electron microscopy (SEM)
Microstructural images of alkali activated hardened paste specimens at 28 days were obtained from
optimum alkali content of 10.41% and SiO2 content of 8 %. Scanning Electron Microscoy (SEM) was used to
record micrographs using a JEOL JSM 6360 scanning electron microscope. Fig. 4 shows the microstructure of
AAGGBS hardened paste specimens having optimum alkali content of 10.41% and SiO2 with 8 % for various
curing conditions ( RH50, RH70, RH90, OC50 and WC) .The formation of C-S-H in the AAGGBS matrix has a
significant effect on the development of compressive strength. The matrix of water cured specimen was
different from other type of specimens as the microstructure was very dense with fewer unreacted slag grains
and voids, hence responsible for higher compressive strength. Microstructure of oven cured (500
C) specimens
shown the micro cracks as clearly observed from Fig. 4 (d).
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Figure 3: The Effect of alkali content on compressive strength under different curing conditions.
Figure 4: SEM micrograph of alkali activated GGBS with different curing conditions with 10.41% alkali
content and 8% SiO2 (a) RH50, (b) RH70, (c) RH90, (d) OC50 and (e) WC.
(b)
(c) (d)
(a)
(e)
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IV. CONCLUSION
Based on the experimental investigation, the following conclusions are drawn.
The higher strength was obtained from water cured specimens for all types of alkali contents. The
optimum alkali content (K2O + Na2O) was found to be 10.41 % with a SiO2/(K2O+Na2O) ratio of 0 .76.
The maximum strength of 50.20 MPa was obtained from water cured sample having 10.41 % alkali
content. (Fig.1c, 2c and Fig.3).
The oven curing is more sensitive for alkali activated slag. The micro cracks were observed on the
surface of the specimens as observed in the SEM image (Fig. 4d).
Curing conditions had a significant effect on the mechanical behavior in the hardened state of alkali
activated slag paste. The compressive strength of the alkali activated blast furnace slag paste can be
controlled by judiciously choosing the curing conditions.
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AUTHOR’S BIOGRAPHY
Mohd. Nadeem Qureshi, M.E., MBA, C Eng. is working as a Senior Lecturer in Civil
Engineering Department of Government Polytechnic, Khamgaon. (M.S), India. He is
presently pursuing Ph.D in the field of „Alkali-activated Blast Furnace Slag Composite‟ at
Jadavpur University, Kolkata - 7000 32 (India), under QIP Program. He did his Masters in
Structural Engineering from M.S.University of Baroda in 1991. He earned a diploma in
Construction from George Brown College, Toronto (Canada) He has gold seal certification in
steel construction from Ontario General Contractors Association (Canada). Mr. Qureshi has
over 20 years of teaching and industrial experience at the national and international level. He has worked from
1991 to 1999 as Civil and Structural Engineer for Thinet International Co. Paris France and Issam Kabbani and
partners Co. for their various projects in gulf countries.
Mr. Qureshi is a member of ISTE, IEI, ISET, IWWA, NICE, ACERS and ACI.
Mobile: 09403313195, md.kureshi@gmail.com
Dr. Somnath Ghosh, PhD, MBA is presently serving as Professor of Civil Engineering,
Jadavpur University, Kolkata- 7000 32. (India). Dr. Ghosh has over 30 yrs of Teaching,
Research and Industrial experience He is also a consultant to a number of prestigious projects
at national level. He has authored 6 books through an international publishing agency in
Germany and published several papers in peer reviewed national and international journals.
Dr. Ghosh has contributed significantly in the area of High performance concrete,
Geopolymer composites and FEM analysis of concrete structures. His contribution on „Fly ash based
Geopolymer composite‟ has added a new dimension in the area of non-conventional green binder material using
waste and is acclaimed internationally.
Dr. Ghosh has demonstrated his skill by providing technical advice on a number of occasions and the same has
been implemented very successfully in practice. Repair and restoration techniques adopted for the earthquake
damaged structures of the Kandla special economic zone (SEZ) through his expertise deserve a special mention.
Another noteworthy contribution is the restoration of Assembly building at Sikkim. His skill in computer aided
analysis of structure has been demonstrated through the design of a Buddha statue of 52m tall, on the top of a
hill at Namchi, Sikkim and a cricket stadium in Guwahati. His selection as the Country Head of a division in a
multinational company in Nigeria speaks about his skill and expertise. During this period, Dr. Ghosh has
successfully guided a good number of students for their Ph.D and Master‟s degree. He has acted as expert
member on several occasions for CSIR, AICTE, UGC, IIT, NIT & other Universities. Dr. Ghosh has contributed
immensely both in academics as well as in practice through his activities.
Mobile: 09831025676, som_ghosh2000@yahoo.com.