This document investigates the effects of adding slag and limestone powder to alkali-activated metakaolin. Tests were conducted on mixtures with 0-40% slag replacement and 0-20% limestone powder addition. Results showed that slag decreased setting time and initially increased compressive strength up to an optimal slag content. Limestone at 15% improved strength but did not affect reaction products. Analysis using XRD, FTIR and SEM showed changes in reaction products with slag but not limestone, indicating limestone acts as a non-reactive filler.
IRJET- Study of Mechanical Properties of Fly Ash Based Geopolymer ConcreteIRJET Journal
This study evaluated the mechanical properties of fly ash-based geopolymer concrete and compared them to conventional cement concrete. Fly ash-based geopolymer concrete specimens were cast and tested for properties like compressive strength, splitting tensile strength, and modulus of elasticity after 7 days of curing. The test results showed that the geopolymer concrete exhibited higher strengths and elastic modulus than required code values for conventional cement concrete after the same curing period. However, geopolymer concrete workability was lower and required heat curing which can be addressed by adding cement. Overall, the study demonstrated that geopolymer concrete has potential to be a more sustainable alternative to cement concrete.
Effect of Severe Environmental Exposure on Properties of Geopolymer ConcreteIRJET Journal
This document summarizes a research study on the effect of severe environmental exposure on the properties of geopolymer concrete. The study developed geopolymer concrete with fly ash as the binder material activated with sodium hydroxide and sodium silicate solutions. Specimens were tested for compressive, tensile, and flexural strength after curing and after immersion in 5% sulfuric acid for periods of time. Results showed geopolymer concrete achieved compressive strengths from 32-38 MPa and had higher residual strengths after acid exposure compared to ordinary Portland cement concrete. The study aimed to evaluate the durability and acid resistance of fly ash geopolymer concrete.
Short term properties of High Calcium Flyashbased Geopolymer binderIOSRJMCE
The past decades of research is diverted primarily in making concrete without cement or atleast partially replacing by suitable alternatives. For its availability and problems associated with, flyash has been given priority to use in concrete in high volume or total replacement of cement resulting in geopolymer concrete using activated flyash of low calcium type as the source material. However, few are dealt on the high calcium flyash that too mainly on achieving the required compressive strength and not much on the short term engineering properties like consistency and setting characteristicseven though itis essential to establish the time available for placing, compaction and transport of geopolymer. Therefore, a fundamental study on the setting characteristics and strength development of high calcium flyash based geopolymer with varying concentration of Sodium hydroxide(8-14M),varying liquid ratios (1.5-3.0) of the activator and curing at ambient and 65oCtemperature is made.It is observed that the consistency of flyash based geopolymer increases with increase of concentration of NaOH and is not at all influenced by the liquid ratios considered but, the setting time is reduced by oven curing obviously. Also, the mortar strength is atleast 10% more for hot curing than ambient curing.
Rh/CeO2 Thin Catalytic Layer Deposition on Alumina Foams: Catalytic Performan...CarmenMoncada10
The document describes the deposition of Rh/CeO2 catalytic coatings on alumina open-cell foam (OCF) structures with different pore densities using a solution combustion synthesis method. Three OCF structures with pore densities of 20, 30, and 40 pores per square inch were characterized in terms of their geometric properties. The coated structures were then evaluated for their catalytic performance in biogas steam reforming and oxy-steam reforming reactions. Characterization techniques like SEM, TEM, and ultrasound tests showed that homogeneous, thin, and adhesion coatings were deposited on the OCF struts via the solution combustion synthesis method. The coatings displayed high catalytic activity that followed the order of 20 ppi < 30 ppi ~ 40
Magnetic Fe3O4@MgAl–LDH composite grafted with cobalt phthalocyanine as an ef...Pawan Kumar
Magnetically separable layered double hydroxide MgAl–LDH@Fe3O4 composite supported cobalt
phthalocyanine catalyst was synthesized and used for the aerobic oxidation of mercaptans to corresponding
disulfides under alkali free conditions. The catalyst exhibited excellent activity for the oxidation of
mercaptans using molecular oxygen as an oxidant which can be effectively recovered by using an external
magnetic field. In addition, the covalent immobilization of cobalt phthalocyanine to MgAl–LDH@Fe3O4
support prevents the leaching of the catalyst and improves its activity and stability
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
IRJET - Magnesium Oxychloride Cement with Partial Replacement of Fly Ash and ...IRJET Journal
This document discusses research into magnesium oxychloride cement (MOC) with partial replacement of fly ash and magnesium sulphate. MOC-fly ash mixes were evaluated with various compositions. When fly ash was 20% of the MgO content, the MOC mix attained high strength compared to other combinations after air curing. The MOC-fly ash mix set within 4 hours and showed good workability, aggregate-cement bonding, and compressive strengths ranging from 20-68MPa. The document provides details on the materials used, including their chemical compositions and properties. The methodology for preparing Sorel cement pastes using molar ratios of MgO and MgCl2 is also described.
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.
IRJET- Study of Mechanical Properties of Fly Ash Based Geopolymer ConcreteIRJET Journal
This study evaluated the mechanical properties of fly ash-based geopolymer concrete and compared them to conventional cement concrete. Fly ash-based geopolymer concrete specimens were cast and tested for properties like compressive strength, splitting tensile strength, and modulus of elasticity after 7 days of curing. The test results showed that the geopolymer concrete exhibited higher strengths and elastic modulus than required code values for conventional cement concrete after the same curing period. However, geopolymer concrete workability was lower and required heat curing which can be addressed by adding cement. Overall, the study demonstrated that geopolymer concrete has potential to be a more sustainable alternative to cement concrete.
Effect of Severe Environmental Exposure on Properties of Geopolymer ConcreteIRJET Journal
This document summarizes a research study on the effect of severe environmental exposure on the properties of geopolymer concrete. The study developed geopolymer concrete with fly ash as the binder material activated with sodium hydroxide and sodium silicate solutions. Specimens were tested for compressive, tensile, and flexural strength after curing and after immersion in 5% sulfuric acid for periods of time. Results showed geopolymer concrete achieved compressive strengths from 32-38 MPa and had higher residual strengths after acid exposure compared to ordinary Portland cement concrete. The study aimed to evaluate the durability and acid resistance of fly ash geopolymer concrete.
Short term properties of High Calcium Flyashbased Geopolymer binderIOSRJMCE
The past decades of research is diverted primarily in making concrete without cement or atleast partially replacing by suitable alternatives. For its availability and problems associated with, flyash has been given priority to use in concrete in high volume or total replacement of cement resulting in geopolymer concrete using activated flyash of low calcium type as the source material. However, few are dealt on the high calcium flyash that too mainly on achieving the required compressive strength and not much on the short term engineering properties like consistency and setting characteristicseven though itis essential to establish the time available for placing, compaction and transport of geopolymer. Therefore, a fundamental study on the setting characteristics and strength development of high calcium flyash based geopolymer with varying concentration of Sodium hydroxide(8-14M),varying liquid ratios (1.5-3.0) of the activator and curing at ambient and 65oCtemperature is made.It is observed that the consistency of flyash based geopolymer increases with increase of concentration of NaOH and is not at all influenced by the liquid ratios considered but, the setting time is reduced by oven curing obviously. Also, the mortar strength is atleast 10% more for hot curing than ambient curing.
Rh/CeO2 Thin Catalytic Layer Deposition on Alumina Foams: Catalytic Performan...CarmenMoncada10
The document describes the deposition of Rh/CeO2 catalytic coatings on alumina open-cell foam (OCF) structures with different pore densities using a solution combustion synthesis method. Three OCF structures with pore densities of 20, 30, and 40 pores per square inch were characterized in terms of their geometric properties. The coated structures were then evaluated for their catalytic performance in biogas steam reforming and oxy-steam reforming reactions. Characterization techniques like SEM, TEM, and ultrasound tests showed that homogeneous, thin, and adhesion coatings were deposited on the OCF struts via the solution combustion synthesis method. The coatings displayed high catalytic activity that followed the order of 20 ppi < 30 ppi ~ 40
Magnetic Fe3O4@MgAl–LDH composite grafted with cobalt phthalocyanine as an ef...Pawan Kumar
Magnetically separable layered double hydroxide MgAl–LDH@Fe3O4 composite supported cobalt
phthalocyanine catalyst was synthesized and used for the aerobic oxidation of mercaptans to corresponding
disulfides under alkali free conditions. The catalyst exhibited excellent activity for the oxidation of
mercaptans using molecular oxygen as an oxidant which can be effectively recovered by using an external
magnetic field. In addition, the covalent immobilization of cobalt phthalocyanine to MgAl–LDH@Fe3O4
support prevents the leaching of the catalyst and improves its activity and stability
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
IRJET - Magnesium Oxychloride Cement with Partial Replacement of Fly Ash and ...IRJET Journal
This document discusses research into magnesium oxychloride cement (MOC) with partial replacement of fly ash and magnesium sulphate. MOC-fly ash mixes were evaluated with various compositions. When fly ash was 20% of the MgO content, the MOC mix attained high strength compared to other combinations after air curing. The MOC-fly ash mix set within 4 hours and showed good workability, aggregate-cement bonding, and compressive strengths ranging from 20-68MPa. The document provides details on the materials used, including their chemical compositions and properties. The methodology for preparing Sorel cement pastes using molar ratios of MgO and MgCl2 is also described.
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.
IRJET-Comparative Study of Strength & Cost of Fibre Reinforced Geopolymer Con...IRJET Journal
This document presents the results of an experimental study comparing the strength and cost of fibre-reinforced geopolymer concrete and conventional concrete. Geopolymer concrete is made from fly ash, alkaline liquids like sodium silicate and sodium hydroxide, aggregates, and sometimes fibres. It offers an eco-friendly alternative to ordinary Portland cement concrete. The study found that using glass fibres increased the compressive strength of geopolymer concrete by about 18% compared to non-fibre concrete. Steel fibres also increased the split tensile strength significantly. While geopolymer concrete achieved high early strength within 7 days, conventional concrete continued gaining strength beyond 7 days. In terms of cost, geopolymer concrete provides savings over conventional
IRJET- Sulphuric Acid Durability Studies of Concrete with Portland Cement (CE...IRJET Journal
This document summarizes a study on the sulphuric acid durability of concrete with different cement types and partial cement replacements. Concrete cubes were made with Portland cement (CEM I), Portland composite cements (CEM II/A-M and CEM II/B-M), and with partial replacements of Portland cement with fly ash and GGBFS. Cubes were submerged in 5% sulphuric acid for 90 days. Results showed concrete with higher Portland cement content was most affected, while CEM II/B-M concrete was most durable. Partial replacements of 25% fly ash and 70% GGBFS showed higher durability against sulphuric acid attack compared to the reference mix.
This document discusses an experimental study on the effect of phosphate ions on the preparation of fly ash-based geopolymers. Fly ash was activated using a solution of sodium aluminium phosphate, with curing done atmospherically and through accelerated heating. Compressive strength was found to increase with higher activator concentrations and longer curing times. Accelerated curing at 60°C produced strengths 70% of the final strength within 4-5 hours. FTIR analysis showed structural changes after geopolymerization. The presence of phosphate ions was found to improve the strength properties of the fly ash geopolymers.
Synthesis of geopolymer from indonesian kaolin and fly ash as a green constru...Pambudi Pajar Pratama
The cement industry is a substantial contributor to the global greenhouse gases emissions, accounting for approximatley 6% of the total global CO2 emission. Geopolymer, an inorganic polymer consisting primarily of Si-Al-O covalent chains, is an attractive alternative to the conventional portland cement due to its much smaller carbon footprint. This research is an early work aimed at elucidating the techno-economic feasibility of geopolymer production in Indonesia, utilizing domestic aluminosilicate minerals and waste materials as feedstocks. Kaolin from the Belitung island and Class F coal fly ash from an electric powerplant in East Java were selected as the geopolymer precursors. The kaolin was initially calcined at 750 oC for 6 hours to convert it to the much more reactive metakaolin phase. Besides the type of aluminosilicate raw materials, the type of alkali solution was also varied between NaOH and KOH. The aluminosilicate materials were each reacted with 10.0 M alkali hydroxide solution at a solid-to-liquid mass ratio of 1.2 and 2.8 for the case of metakaolin and fly ash, respectively. The effect of these variables was evaluated on mortars prepared by using the obtained geopolymers, which involved the measurement of settling time in accordance to an Indonesian standard Vicat apparatus method, and compressive strength according to the ASTM C 109-80 method. The setting time of fly ash - KOH/NaOH geopolymer mortars is shorter than those obtained using metakaolin, due to the higher reactivity of the amorphous fly ash. The higher reactivity of fly ash also promotes better crosslinking of the Si-Al-O bonds, resulting in a higher compressive strength compared to the metakaolin-based geopolymer samples.
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.
This document describes a study that uses an iron-squarate based 3D metal-organic framework (FeSq-MOF) as a heterogeneous catalyst for transforming tetrazines into oxadiazole derivatives at room temperature. The FeSq-MOF was found to efficiently catalyze the reaction of various tetrazine substrates to their corresponding oxadiazole products in yields ranging from 53-97% within 1-24 hours, depending on the substrate. Testing confirmed the heterogeneous nature of the catalysis and that no iron leaching occurred. The FeSq-MOF could be recycled for multiple reaction cycles with only a moderate decrease in yield after the third cycle. This new catalytic method provides a simple, mild, and
This document summarizes a study on the effect of various synthesis parameters on the setting time and workability of fly ash-based geopolymer paste and mortar. Specifically, it examines the effect of alkali content (Na2O/Al2O3 ratio), silica content (SiO2/Al2O3 ratio), and water-to-binder ratio. The study found that initial and final setting time decreased with increasing alkali content and water-to-binder ratio, but increased with increasing silica content. Workability, as measured by flow table tests, also decreased with higher alkali content and water-to-binder ratio. The results provide an understanding of how synthesis parameters influence
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.
Corrosion studies of colmonoy - 6 in nitric acid during gadolinium removal st...RAMASUBBU VELAYUTHAM
This document summarizes a study on the corrosion of Colmonoy-6, a nickel-based alloy used in valves and bearings of nuclear power plant moderator systems, when exposed to nitric acid conditions present during gadolinium removal from the moderator. Specimens of undiluted Colmonoy-6 deposits and Colmonoy-6 coatings on stainless steel with varying levels of dilution were exposed to a nitric acid solution at 65°C, and corrosion rates were estimated through weight loss and electrochemical measurements. Microstructural analysis found the undiluted deposit and multiple layer coatings contained more carbide and boride precipitates than single layer coatings, indicating lower dilution effects.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document presents the results of a study comparing the hardened concrete properties of mixes containing micro silica or alccofine as supplementary cementitious materials. Concrete cubes, beams, and cylinders were cast with micro silica or alccofine added to cement at increments of 0%, 3.34%, 6.68%, 10.02%, 13.36%, and 16.7%. The hardened properties tested included compressive strength, flexural strength, splitting tensile strength, and impact resistance. Test results showed that the concretes with micro silica and alccofine additions generally exhibited higher strength properties compared to the control mix without additions.
IRJET- Study on Mechanical and Structural Properties of Geopolymer Concrete M...IRJET Journal
This document summarizes a study on the mechanical and structural properties of geopolymer concrete made with recycled aggregates. Six mixes of geopolymer concrete beams were cast with different proportions of fly ash, ground granulated blast furnace slag, and partial replacement of recycled coarse aggregates. The beams were tested to determine properties like compressive strength, flexural strength, load-deflection behavior, crack patterns, and failure modes. Test results showed that geopolymer concrete with recycled aggregates exhibited improved mechanical and structural performance compared to a control mix.
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.
Effect of Partial Replacement of Cement by Silica Fume and Sand by Quarry Dus...IRJET Journal
This study investigated the effect of partially replacing cement with silica fume and sand with quarry dust on the strength and durability of concrete. Concrete mixtures were prepared with 8-12% silica fume and 20-40% quarry dust replacements. Testing showed that 10% silica fume and 30% quarry dust replacements increased compressive strength the most at 18.5% over the control mix. This mix also demonstrated the highest durability with the lowest rapid chloride permeability. Workability decreased with higher silica fume and quarry dust content due to their finer particles and higher water absorption. The study concluded that using 10% silica fume and 30% quarry dust provided environmental and economic benefits over
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
A Study on Strength Properties of Concrete Made with Waste Ready-Mix Concrete...IRJET Journal
This document presents a study on the strength properties of concrete made with waste ready-mix concrete as coarse aggregate and partial replacement of cement by ground granulated blast furnace slag (GGBS). Various mixes were designed to replace natural coarse aggregate with recycled coarse aggregate at percentages of 20%, 40%, and 60%. Cubes and cylinders were cast and tested to determine the compressive and split tensile strengths of the mixes at 28 days. The results showed that concrete with recycled coarse aggregate and GGBS replacement achieved comparable strength to conventional concrete. Finite element analysis was also conducted to validate the experimental results. The study concludes that waste ready-mix concrete can effectively be used as coarse aggregate in concrete production.
As cement is been involved in various contrived effects to the environment, an alternative is necessary for its impacts reduction.Such alternative is done by completely replacing the cement with silicafume and flyash which are the by-products.
Experimental Study on Mechanical Properties of Fly Ash and GGBS Based Geopoly...IRJET Journal
This document presents an experimental study on the mechanical properties of fly ash and ground granulated blast furnace slag (GGBS) based geopolymer concrete. Different mixes were prepared by replacing fly ash at 0%, 25%, 50%, 75% and 100% levels with GGBS. The concrete was tested for compressive strength, split tensile strength and flexural strength at 3, 7 and 28 days of curing. Both oven curing at 60°C and ambient curing were used. The results showed that replacement of fly ash by GGBS eliminated the need for heat curing of geopolymer concrete. Geopolymer concrete exhibited better mechanical properties than normal concrete and its strength developed rapidly at early ages, making
This document summarizes research on modifying an epoxy resin with epoxidized sunflower oil (ESO) and assessing the impact on material properties. Two processes for incorporating ESO into the epoxy resin were tested: a one-stage and two-stage process. Results showed the two-stage process produced materials with greater impact strength, fracture toughness, and decomposition temperature compared to the one-stage process. Specifically, the polymer composite achieved the best properties when containing 5% ESO using the two-stage process, improving the toughness and strength of the material.
Optimization of alkali activation of ground granulated slag with mining tailseSAT Publishing House
This document describes an experiment to optimize the formulation of an alkali-activated ground granulated blast furnace slag composite by adding mining tails and wollastonite microfibers. Previous research achieved a 7-day compressive strength of 55.15 MPa with 10% wollastonite but the formulation was too expensive. The current study tested adding mine tailings to reduce costs while maintaining strength. Results showed that with 2 parts mine tailings and 20% wollastonite, the 7-day strength was 41.36 MPa and costs were reduced by 2/3. A design of experiments then evaluated compressive strength with varying levels of mine tailings and wollastonite.
Experimental investigation of micro reinforced, alkali-activated ground granu...eSAT Publishing House
This document presents the results of an experimental investigation into reinforcing alkali-activated ground granulated blast furnace slag with wollastonite microfibers. Compressive strength, setting time, and microscopic structure of the mixtures were analyzed as functions of wollastonite type and percentage. Adding up to 30% wollastonite significantly increased compressive strength, with the optimal loading providing a 60% increase, and reduced setting time, especially at higher loadings. Cost was found to be about 6 times higher than ordinary Portland cement concrete. Alternative applications were explored due to the high cost.
Alkali activated binders produced from petrochemical fluid catalytic cracking...eSAT Publishing House
This document summarizes research on producing alkali-activated binders using waste from a petrochemical fluid catalytic cracking (FCC) catalyst. Mortars and cement pastes were made with varying ratios of the FCC catalyst waste and calcium hydroxide. Tests showed that higher calcium hydroxide content led to higher compressive strength in the hardened mortars. Analysis of the hardened pastes using Fourier transform infrared spectroscopy and X-ray diffraction confirmed alkali-activation of the FCC catalyst waste, resulting in both amorphous and crystalline reaction products. The initial ratio of solids was found to influence the reaction kinetics and mechanisms of the alkali-activation process.
This document summarizes the results of a study investigating the effects of ultra-fine materials on the workability and strength of concrete containing alkali-activated slag as the binder. It was found that:
1) Partial replacement of slag with ultra-fine fly ash improved workability but had similar strength development as ordinary portland cement concrete.
2) Partial replacement with condensed silica fume or ultra-fine slag showed significantly greater strength than alkali-activated slag concrete at ages greater than one day, though condensed silica fume reduced workability.
3) Of the mixes tested, concrete with partial replacement of slag with condensed silica fume achieved the highest compressive strength over 91 days of
IRJET-Comparative Study of Strength & Cost of Fibre Reinforced Geopolymer Con...IRJET Journal
This document presents the results of an experimental study comparing the strength and cost of fibre-reinforced geopolymer concrete and conventional concrete. Geopolymer concrete is made from fly ash, alkaline liquids like sodium silicate and sodium hydroxide, aggregates, and sometimes fibres. It offers an eco-friendly alternative to ordinary Portland cement concrete. The study found that using glass fibres increased the compressive strength of geopolymer concrete by about 18% compared to non-fibre concrete. Steel fibres also increased the split tensile strength significantly. While geopolymer concrete achieved high early strength within 7 days, conventional concrete continued gaining strength beyond 7 days. In terms of cost, geopolymer concrete provides savings over conventional
IRJET- Sulphuric Acid Durability Studies of Concrete with Portland Cement (CE...IRJET Journal
This document summarizes a study on the sulphuric acid durability of concrete with different cement types and partial cement replacements. Concrete cubes were made with Portland cement (CEM I), Portland composite cements (CEM II/A-M and CEM II/B-M), and with partial replacements of Portland cement with fly ash and GGBFS. Cubes were submerged in 5% sulphuric acid for 90 days. Results showed concrete with higher Portland cement content was most affected, while CEM II/B-M concrete was most durable. Partial replacements of 25% fly ash and 70% GGBFS showed higher durability against sulphuric acid attack compared to the reference mix.
This document discusses an experimental study on the effect of phosphate ions on the preparation of fly ash-based geopolymers. Fly ash was activated using a solution of sodium aluminium phosphate, with curing done atmospherically and through accelerated heating. Compressive strength was found to increase with higher activator concentrations and longer curing times. Accelerated curing at 60°C produced strengths 70% of the final strength within 4-5 hours. FTIR analysis showed structural changes after geopolymerization. The presence of phosphate ions was found to improve the strength properties of the fly ash geopolymers.
Synthesis of geopolymer from indonesian kaolin and fly ash as a green constru...Pambudi Pajar Pratama
The cement industry is a substantial contributor to the global greenhouse gases emissions, accounting for approximatley 6% of the total global CO2 emission. Geopolymer, an inorganic polymer consisting primarily of Si-Al-O covalent chains, is an attractive alternative to the conventional portland cement due to its much smaller carbon footprint. This research is an early work aimed at elucidating the techno-economic feasibility of geopolymer production in Indonesia, utilizing domestic aluminosilicate minerals and waste materials as feedstocks. Kaolin from the Belitung island and Class F coal fly ash from an electric powerplant in East Java were selected as the geopolymer precursors. The kaolin was initially calcined at 750 oC for 6 hours to convert it to the much more reactive metakaolin phase. Besides the type of aluminosilicate raw materials, the type of alkali solution was also varied between NaOH and KOH. The aluminosilicate materials were each reacted with 10.0 M alkali hydroxide solution at a solid-to-liquid mass ratio of 1.2 and 2.8 for the case of metakaolin and fly ash, respectively. The effect of these variables was evaluated on mortars prepared by using the obtained geopolymers, which involved the measurement of settling time in accordance to an Indonesian standard Vicat apparatus method, and compressive strength according to the ASTM C 109-80 method. The setting time of fly ash - KOH/NaOH geopolymer mortars is shorter than those obtained using metakaolin, due to the higher reactivity of the amorphous fly ash. The higher reactivity of fly ash also promotes better crosslinking of the Si-Al-O bonds, resulting in a higher compressive strength compared to the metakaolin-based geopolymer samples.
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.
This document describes a study that uses an iron-squarate based 3D metal-organic framework (FeSq-MOF) as a heterogeneous catalyst for transforming tetrazines into oxadiazole derivatives at room temperature. The FeSq-MOF was found to efficiently catalyze the reaction of various tetrazine substrates to their corresponding oxadiazole products in yields ranging from 53-97% within 1-24 hours, depending on the substrate. Testing confirmed the heterogeneous nature of the catalysis and that no iron leaching occurred. The FeSq-MOF could be recycled for multiple reaction cycles with only a moderate decrease in yield after the third cycle. This new catalytic method provides a simple, mild, and
This document summarizes a study on the effect of various synthesis parameters on the setting time and workability of fly ash-based geopolymer paste and mortar. Specifically, it examines the effect of alkali content (Na2O/Al2O3 ratio), silica content (SiO2/Al2O3 ratio), and water-to-binder ratio. The study found that initial and final setting time decreased with increasing alkali content and water-to-binder ratio, but increased with increasing silica content. Workability, as measured by flow table tests, also decreased with higher alkali content and water-to-binder ratio. The results provide an understanding of how synthesis parameters influence
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.
Corrosion studies of colmonoy - 6 in nitric acid during gadolinium removal st...RAMASUBBU VELAYUTHAM
This document summarizes a study on the corrosion of Colmonoy-6, a nickel-based alloy used in valves and bearings of nuclear power plant moderator systems, when exposed to nitric acid conditions present during gadolinium removal from the moderator. Specimens of undiluted Colmonoy-6 deposits and Colmonoy-6 coatings on stainless steel with varying levels of dilution were exposed to a nitric acid solution at 65°C, and corrosion rates were estimated through weight loss and electrochemical measurements. Microstructural analysis found the undiluted deposit and multiple layer coatings contained more carbide and boride precipitates than single layer coatings, indicating lower dilution effects.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document presents the results of a study comparing the hardened concrete properties of mixes containing micro silica or alccofine as supplementary cementitious materials. Concrete cubes, beams, and cylinders were cast with micro silica or alccofine added to cement at increments of 0%, 3.34%, 6.68%, 10.02%, 13.36%, and 16.7%. The hardened properties tested included compressive strength, flexural strength, splitting tensile strength, and impact resistance. Test results showed that the concretes with micro silica and alccofine additions generally exhibited higher strength properties compared to the control mix without additions.
IRJET- Study on Mechanical and Structural Properties of Geopolymer Concrete M...IRJET Journal
This document summarizes a study on the mechanical and structural properties of geopolymer concrete made with recycled aggregates. Six mixes of geopolymer concrete beams were cast with different proportions of fly ash, ground granulated blast furnace slag, and partial replacement of recycled coarse aggregates. The beams were tested to determine properties like compressive strength, flexural strength, load-deflection behavior, crack patterns, and failure modes. Test results showed that geopolymer concrete with recycled aggregates exhibited improved mechanical and structural performance compared to a control mix.
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.
Effect of Partial Replacement of Cement by Silica Fume and Sand by Quarry Dus...IRJET Journal
This study investigated the effect of partially replacing cement with silica fume and sand with quarry dust on the strength and durability of concrete. Concrete mixtures were prepared with 8-12% silica fume and 20-40% quarry dust replacements. Testing showed that 10% silica fume and 30% quarry dust replacements increased compressive strength the most at 18.5% over the control mix. This mix also demonstrated the highest durability with the lowest rapid chloride permeability. Workability decreased with higher silica fume and quarry dust content due to their finer particles and higher water absorption. The study concluded that using 10% silica fume and 30% quarry dust provided environmental and economic benefits over
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
A Study on Strength Properties of Concrete Made with Waste Ready-Mix Concrete...IRJET Journal
This document presents a study on the strength properties of concrete made with waste ready-mix concrete as coarse aggregate and partial replacement of cement by ground granulated blast furnace slag (GGBS). Various mixes were designed to replace natural coarse aggregate with recycled coarse aggregate at percentages of 20%, 40%, and 60%. Cubes and cylinders were cast and tested to determine the compressive and split tensile strengths of the mixes at 28 days. The results showed that concrete with recycled coarse aggregate and GGBS replacement achieved comparable strength to conventional concrete. Finite element analysis was also conducted to validate the experimental results. The study concludes that waste ready-mix concrete can effectively be used as coarse aggregate in concrete production.
As cement is been involved in various contrived effects to the environment, an alternative is necessary for its impacts reduction.Such alternative is done by completely replacing the cement with silicafume and flyash which are the by-products.
Experimental Study on Mechanical Properties of Fly Ash and GGBS Based Geopoly...IRJET Journal
This document presents an experimental study on the mechanical properties of fly ash and ground granulated blast furnace slag (GGBS) based geopolymer concrete. Different mixes were prepared by replacing fly ash at 0%, 25%, 50%, 75% and 100% levels with GGBS. The concrete was tested for compressive strength, split tensile strength and flexural strength at 3, 7 and 28 days of curing. Both oven curing at 60°C and ambient curing were used. The results showed that replacement of fly ash by GGBS eliminated the need for heat curing of geopolymer concrete. Geopolymer concrete exhibited better mechanical properties than normal concrete and its strength developed rapidly at early ages, making
This document summarizes research on modifying an epoxy resin with epoxidized sunflower oil (ESO) and assessing the impact on material properties. Two processes for incorporating ESO into the epoxy resin were tested: a one-stage and two-stage process. Results showed the two-stage process produced materials with greater impact strength, fracture toughness, and decomposition temperature compared to the one-stage process. Specifically, the polymer composite achieved the best properties when containing 5% ESO using the two-stage process, improving the toughness and strength of the material.
Optimization of alkali activation of ground granulated slag with mining tailseSAT Publishing House
This document describes an experiment to optimize the formulation of an alkali-activated ground granulated blast furnace slag composite by adding mining tails and wollastonite microfibers. Previous research achieved a 7-day compressive strength of 55.15 MPa with 10% wollastonite but the formulation was too expensive. The current study tested adding mine tailings to reduce costs while maintaining strength. Results showed that with 2 parts mine tailings and 20% wollastonite, the 7-day strength was 41.36 MPa and costs were reduced by 2/3. A design of experiments then evaluated compressive strength with varying levels of mine tailings and wollastonite.
Experimental investigation of micro reinforced, alkali-activated ground granu...eSAT Publishing House
This document presents the results of an experimental investigation into reinforcing alkali-activated ground granulated blast furnace slag with wollastonite microfibers. Compressive strength, setting time, and microscopic structure of the mixtures were analyzed as functions of wollastonite type and percentage. Adding up to 30% wollastonite significantly increased compressive strength, with the optimal loading providing a 60% increase, and reduced setting time, especially at higher loadings. Cost was found to be about 6 times higher than ordinary Portland cement concrete. Alternative applications were explored due to the high cost.
Alkali activated binders produced from petrochemical fluid catalytic cracking...eSAT Publishing House
This document summarizes research on producing alkali-activated binders using waste from a petrochemical fluid catalytic cracking (FCC) catalyst. Mortars and cement pastes were made with varying ratios of the FCC catalyst waste and calcium hydroxide. Tests showed that higher calcium hydroxide content led to higher compressive strength in the hardened mortars. Analysis of the hardened pastes using Fourier transform infrared spectroscopy and X-ray diffraction confirmed alkali-activation of the FCC catalyst waste, resulting in both amorphous and crystalline reaction products. The initial ratio of solids was found to influence the reaction kinetics and mechanisms of the alkali-activation process.
This document summarizes the results of a study investigating the effects of ultra-fine materials on the workability and strength of concrete containing alkali-activated slag as the binder. It was found that:
1) Partial replacement of slag with ultra-fine fly ash improved workability but had similar strength development as ordinary portland cement concrete.
2) Partial replacement with condensed silica fume or ultra-fine slag showed significantly greater strength than alkali-activated slag concrete at ages greater than one day, though condensed silica fume reduced workability.
3) Of the mixes tested, concrete with partial replacement of slag with condensed silica fume achieved the highest compressive strength over 91 days of
This document discusses how the pore size distribution affects drying shrinkage in alkali-activated slag concrete (AASC) compared to ordinary Portland cement concrete (OPCC). The main points are:
1) AASC exhibited higher drying shrinkage than OPCC even though OPCC lost more moisture during drying.
2) The pore size distribution of AASC pastes showed a much higher proportion of pores in the mesopore region compared to OPC pastes.
3) The radius of pores where the meniscus forms during drying seems to be a more important factor for shrinkage than the total moisture loss. This supports the theory that capillary tensile forces from drying cause shrinkage.
The Leading manufacturers, Suppliers, importers and exporters of a varied range of Carbon Products Calcined Petroleum Coke, Petroleum Coke, Cement & Cement Clinker, Petroleum ProductsPetroleum Products
Effect of activator dosage... (2014, SAICE, Shekhovtsova J)Maxim Kovtun
This document provides biographies of three researchers - Julia Shekhovtsova, Elsabe Kearsley, and Maxim Kovtun - from the University of Pretoria, South Africa. It discusses their educational backgrounds and fields of research, which include the use of fly ash in alkali-activated cement binders and building materials. The document also provides their contact details.
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 paper investigates the workability and mechanical properties of concrete containing alkali-activated slag as the binder. Two types of activators were used: sodium hydroxide with sodium carbonate, and sodium silicate with hydrated lime. The fresh and hardened concrete properties of these alkali-activated slag concretes were compared to ordinary portland cement concrete. The results showed that concrete activated with powdered sodium silicate and lime had minimal slump loss over 2 hours and achieved similar 1-day compressive strengths as portland cement concrete when cured at normal temperatures. However, it exhibited higher drying shrinkage. Overall, alkali-activated slag concrete shows potential as a viable alternative to portland cement concrete.
The document discusses how hazardous air pollution control residue can be transformed into a non-hazardous glass material called Plasmarok through plasma technology. Plasmarok can then be used as a cement replacement to create alkali-activated concretes with high compressive strengths over 90 MPa. The properties of these concretes depend on factors like the particle size, chemical composition, and processing method of Plasmarok. Reducing the particle size and increasing the silicon-to-aluminum ratio can improve the strength. Understanding these influencing factors helps develop consistent concrete materials with desirable properties.
The document describes research into developing alkali-activated slag concrete (AASC) for construction use that achieves high early strength. The researchers created a dry powdered activator by blending sodium silicate and hydrated lime that could be pre-blended with slag. When used to make AASC, this resulted in minimal slump loss over time and compressive strengths similar to ordinary Portland cement concrete at one day. However, AASC exhibited higher drying shrinkage than OPCC. Various methods were investigated to reduce the shrinkage of AASC, such as curing regimes and use of shrinkage-reducing admixtures or porous aggregate, with some success in lowering crack tendency and widths.
Early age strength and workability of slag pastes activated by sodium silicatesfrank collins
This document reports on an investigation into activating blast furnace slag with sodium silicates to achieve equivalent one-day strength to Portland cement at normal curing temperatures and reasonable workability. The effects of varying sodium silicate activator dosages on strength and workability are discussed. Tests on pastes, mortars and concretes showed that equivalent one-day strength to Portland cement is possible using sodium silicate activation at normal curing temperatures, with the strength decreasing as the silicate modulus increases. Workability was also found to decrease with increasing activator dosage.
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
This document describes the development of a numerical model to analyze the cracking behavior of alkali-activated slag concrete (AASC) beams subjected to restrained shrinkage. The model accounts for the time-dependent properties of different concrete mixtures, including shrinkage, elastic modulus, creep, and tensile strength. Experimental data on these properties was used to develop time-dependent relationships in the model. The model aims to better understand the contributions of these parameters to cracking risk by comparing model results to experimental cracking data from restrained beam tests of various concrete mixtures.
Cracking tendency of alkali-activated slag concretefrank collins
This document summarizes a study on the cracking tendency of alkali-activated slag concrete (AASC) when subjected to restrained shrinkage. Key findings include:
1) AASC has higher drying shrinkage than ordinary Portland cement concrete (OPCC) which can lead to greater cracking under restrained conditions.
2) In restrained ring tests, AASC cracked within 7 days while OPCC took 168 days to crack, showing AASC has a higher cracking tendency.
3) To better evaluate cracking, researchers developed a restrained beam test where embedded steel rods or a stress magnifier plate provided restraint. Beams with AASC cracked within hours while OPCC took 9 days, further demonstrating the higher
This document summarizes the development of geopolymer applications over 30 years by Prof. Joseph Davidovits and his research organizations. It describes early successes with fire-resistant wood panels in the 1970s, followed by applications of geopolymers in ceramics, bricks, and cement from the 1970s-1980s. A key innovation was developing a low-temperature process to transform kaolinite clay into a geopolymer binder. This led to liquid geopolymer binders in the 1980s and the invention of high-strength geopolymer cement in 1983 through a collaboration between Prof. Davidovits and Lone Star Industries.
Challenges for Concrete. Presenterat av professor Karen Scrivener, vinnare av Swedish Concrete Award 2015, på Träffpunkt Betong 15 den 7 oktober i Stockholm.
1) A trial was conducted injecting an enhanced calcium sorbent called Sorbacal® SPS at Great River Energy's Stanton Station to reduce SO2 emissions and meet regional haze compliance targets.
2) The trial successfully achieved over 85% SO2 removal and emission rates below 0.14 lb/MMBtu, meeting the target.
3) Monitoring of the electrostatic precipitator performance showed only minimal impacts from the sorbent injection, indicating good compatibility between the enhanced calcium sorbent and ESP operation.
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Factors influencing compressive strength of geopolymer concreteeSAT Journals
The document discusses factors that influence the compressive strength of fly ash-based geopolymer concrete. The factors studied included the molarity of sodium hydroxide solution (8M, 14M, 16M), the ratio of sodium hydroxide to sodium silicate (1, 1.5, 2, 2.5), the alkaline liquid to fly ash ratio (0.35, 0.40), and the replacement of water in the sodium silicate solution (10%, 20%, 30%). The highest compressive strength of 54 MPa was achieved with 16M NaOH solution, a NaOH to Na2SiO3 ratio of 2.5, and an alkaline liquid to fly ash ratio of 0.
INVESTIGATION ON GEOPOLYMER CONCRETE KERB STONEIRJET Journal
This document discusses an investigation into using geopolymer concrete for kerb stones as an alternative to ordinary Portland cement concrete. Geopolymer concrete is made from alumino-silicate materials like fly ash instead of cement, reducing the environmental impact. The study aims to develop a drain-integrated kerb system using fly ash-based geopolymer concrete with varying amounts of reclaimed asphalt pavement (RAP) aggregate replacement. Materials were tested and mix proportions were designed for M-40 grade concrete. Specimens were cast and cured, then tested for compressive and flexural strength. Results showed that geopolymer concrete with 0% RAP replacement had the highest strengths compared to mixes with 50% and
This document summarizes a study that investigated replacing part of the quartz component in autoclave cellular concrete with the aluminosilicate rock perlite. The study found that perlite actively participated in chemical reactions during curing, producing hydrated calcium silicates that increased the strength of the concrete. Specifically, replacing 15% of the quartz with perlite increased the compressive strength by 35% and decreased the density by 20%, while maintaining suitable physical and mechanical properties. Analysis showed that the perlite contributed to the formation of 11Å-(Al)-tobermorite and reduced the amount of metastable α-CSH phase present. The optimal microstructure was achieved with 15% replacement of quartz by perlite.
Effect of steel fiber and poly propylene fiber on the strength properties of ...IRJET Journal
This document summarizes a study on the effect of adding steel fibers and polypropylene fibers to fly ash-based geopolymer concrete. The study used low-calcium fly ash as the source material and an alkaline activator solution made from sodium hydroxide and sodium silicate. Steel fibers with an aspect ratio of 60 and polypropylene fibers with an aspect ratio of 240 were added in varying volume fractions to geopolymer concrete mixes. The compressive strength, split tensile strength, and flexural strength of the fiber-reinforced geopolymer concrete beams were then tested and compared to non-fiber mixes.
Evaluation of Performance of Geopolymer Concrete in Acid EnvironmentIRJET Journal
This document evaluates the performance of geopolymer concrete and Portland cement concrete in acid environments. Specimens of both concretes were immersed in 2% sulfuric acid and hydrochloric acid solutions for periods of 28, 56, and 112 days. The weight change and compressive strength of the specimens were measured to analyze their resistance to acid attack. The results showed that geopolymer concrete exhibited higher resistance to both acids compared to Portland cement concrete, with lower weight loss and strength reduction when immersed. Geopolymer concrete therefore has potential for use in acid-prone environments where conventional concrete is vulnerable.
This document summarizes research on the catalytic wet peroxide oxidation of olive oil mill wastewater over zeolite-based catalysts. The researchers prepared a Cu/13X catalyst by ion exchange and tested its activity and stability for reducing phenolic compounds in wastewater. Characterization showed the ion exchange did not affect zeolite structure but a post-treatment calcination at 1273K decreased surface area and increased copper oxide particles. Testing showed the catalyst reduced total phenols in wastewater by over 80% and TOC by 20% with low copper leaching. The research aims to develop an effective treatment to reduce toxicity of olive oil wastewater before conventional biological processing.
Influence of silicone-based hydrophobic admixture on structural and mechanica...IRJET Journal
This document discusses a study that investigated the influence of silicone-based hydrophobic admixtures on the structural and mechanical properties of concrete mortar. Specifically, it examined how adding different percentages of an organosilicone admixture affected the hydration, water repellency, workability, and compressive strength of concrete mixtures. The study found that adding 0.3% admixture increased compressive strength by 11% compared to a reference concrete without admixture. It also significantly reduced water absorption through the concrete by over 80%. The admixture was found to extend the hydration period of the concrete mixtures and maintain workability with less water.
IRJET-An Experimental Study on Effect of Partial Replacement of Normal Weight...IRJET Journal
This study experimentally investigates the effect of partially replacing normal weight aggregates with lightweight aggregates in fly ash based geopolymer concrete. Three types of lightweight aggregates were used as replacements at levels from 0-20%: pumice, LECA (light expanded clay aggregate), and sintagg. The fresh and hardened properties of the resulting lightweight geopolymer concretes were tested, including slump, compressive strength, split tensile strength, and flexural strength after 7, 14, and 28 days of ambient curing. The goal was to develop a greener and lighter concrete that reduces self-weight and construction costs.
This document presents the results of a study that investigated the mechanical properties and durability of mortar mixtures containing calcium carbide kiln dust (CCKD) as a partial replacement for cement. Various mortar mixtures were prepared with CCKD replacement levels ranging from 5% to 40% by weight of binder. The mixtures were tested to determine setting time, consistency, density, compressive strength, and durability when cured in hydrochloric acid solution. The results showed that mixtures with up to 20% CCKD replacement performed similarly to the control mixture in terms of compressive strength and durability. Higher CCKD replacement levels of 30% and above resulted in lower density and compressive strength both in water and acid
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IRJET- An Experimental Study on Concrete Containing GGBFS and Meta Kaolin wit...IRJET Journal
The document presents results from an experimental study on concrete containing ground granulated blast furnace slag (GGBFS) and metakaolin as partial replacements for cement, and calcium carbide residue (CCR) as a partial replacement for fine aggregate. Concrete mixes were prepared with GGBFS and metakaolin replacing 5%, 10%, and 15% of cement by weight, and CCR replacing 5% and 10% of fine aggregate. The compressive strength, flexural strength, and acid resistance of the mixes were tested and compared to a control mix at ages of 28 days. Results showed that concrete containing GGBFS or metakaolin along with CCR achieved comparable or higher strengths than the control mix.
Valorization of an industrial waste (sludge) as an artificial pozzolan in cem...IJERA Editor
The present study fits within the framework of sustainable management of sludge generated from wastewater treatment in industrial network. The studied sludge comes from an industry manufacturing sanitary ceramic products. Physical, chemical and mineralogical characterization was carried out in order to give an identity card to the sludge. We noted the absence of metal pollution. In order to evaluate its pozzolanic character, the industrial sludge has been subjected to thermal activation at various temperatures (from 650°C to 1000°C). The pozzolanic activity was evaluated by physico-chemical and mechanical methods. Pozzolanicity measurement by conductivity, Frattini and Chapelle Test revealed the existence of pozzolanic properties of calcined samples. The best pozzolanic reactivity was obtained for the sample calcined at 800°C. We noticed a decrease in the reactivity of the samples calcined from 850°C. In addition, analysis by means of X-ray diffraction and Fourier transform infrared spectroscopy showed that sludge recrystallization begins at a temperature of 850°C. Pozzolanicity index of the thermally treated samples was determined by measuring the mechanical resistance of mortar specimens previously kept in a saturated lime solution for 28 days. The best pozzolanic activity index was obtained for the sample calcined at 800°C (109.1%). The study of mechanical performances and resistance to chemical attacks of mortars incorporating sludge (calcined at 800°C) with different percentages and at various ages showed an improvement of mechanical and chemical resistance compared to the control mortar (100% cement) . This work is a contribution to the research for new supplying sources of raw materials and additives in the field of construction. It presents a proposition of a promising solution for the valorization of waste material as an additive instead of being discharged into open air dumps causing a major environmental problem.
An Experimental Investigation on Strength Characteristics of Concrete with P...IJMER
One of the approaches in improving the durability of concrete is to use blended cement
materials such as fly ash, silica fume, slag and more recently, metakaolin.. This study presents the results
of different mechanical properties of concrete such as compressive strength, split tensile strength and
flexural concrete by partially replacing cement with metakaolin and silica fume. The replacement of
metakaolin is varied from 10%, 15%, 20% and 25% and silica fume from 6%, 8% and 10%. The property
of concrete in fresh state, that is the workability is also studied during the present investigation.The
optimum doses of silica fume and metakaolin in combination were found to be 6% and 15% (by weight)
respectively, when used as part replacement of ordinary Portland cement.
Stabilization or solidification of iron ore mine tailings using cementeSAT Journals
Abstract Current research emphasis is more on the utilization of materials that are considered as waste. Tailings and fly ash are major category of industrial wastes, whose disposal is problematic from environmental point of view. In this present research, Industrial byproducts, namely, lime (CaO) and class F type fly ash have been used as candidate materials along with the partial addition of ordinary Portland cement (OPC) in the Stabilization/solidification (S/S) of polymetallic iron ore mine tailings (TM). The effectiveness of S/S was assessed by comparing laboratory experimental values obtained from unconfined compressive strength (UCS), hydraulic conductivity and leaching propensity tests of S/S samples with regulatory standards for safe surface disposal of such wastes. Some S/S cured matrices were found unable to provide the required immobilization of pollutants. S/S and 28 days cured mine tailing specimens made with composite binders containing TM/10/0/0, TM/5/0/20, TM/10/0/40 and TM/0/10/40 significantly impaired the solubility of all contaminants investigated and proved successful in fixing metals within the matrix, in addition to achieving adequate UCS and hydraulic conductivity values, thus satisfying regulatory norms (U.S. EPA). Laboratory investigations revealed the TM blends (stabilized materials) were non-hazardous. The test results of this study are encouraging and it may be possible to undertake large-scale fill construction with stabilized tailing material that is sustainable and cost effective. Keywords: Tailing materials, Laboratory study, Compaction characteristics, unconfined compressive strength, Hydraulic conductivity, Heavy metal content.
Comparison of fatigue parameters of alkali activated and ordinary portland ce...eSAT Publishing House
This document compares the fatigue parameters of alkali-activated concrete and ordinary Portland cement concrete. It presents results of static and cyclic fatigue tests on both materials. Under static testing, the compressive strength of alkali-activated concrete was measured over time up to 90 days. Under cyclic fatigue testing, the stress versus number of cycles to failure (S-N curves) were obtained for both concretes in three-point bending tests. The alkali-activated concrete showed a flatter S-N curve with many specimens surviving over 2 million cycles even at high stresses, indicating better fatigue resistance compared to ordinary Portland cement concrete. The results were discussed in terms of using the different concrete types in fatigue-prone applications.
This document summarizes a research study on the effect of using electrically precipitated fly ash (EPFA) as a partial replacement for cement in self-compacting concrete (SCC). The study tested SCC mixes with 0-30% EPFA replacement at 5% intervals. Tests were conducted on fresh properties, mechanical properties like compressive strength, and durability properties like rapid chloride permeability and water sorptivity. Results showed that 20% EPFA replacement provided better results than the control SCC mix, improving properties while also providing economic and environmental benefits through reduced cement usage.
This document summarizes a study on the effect of Alccofine powder on the properties of self-compacting concrete (SCC). Six different SCC mixes were tested: a control mix without Alccofine and mixes with 5%, 10%, and 15% Alccofine content. Test results showed that SCC mixes with 10% Alccofine exhibited superior fresh and hardened properties compared to mixes with lower or higher Alccofine content. Specifically, the 10% Alccofine mix displayed higher compressive strength, flowability, passing ability, and resistance to segregation. The study concluded that addition of an optimized amount of Alccofine, in this case 10%, can improve the self-compatibility
Experimental Study on Various Strength of High Performance Concrete by using ...IRJET Journal
This document presents an experimental study on the effects of using metakaolin and nano-silica on the strength properties of high performance concrete. Concrete cubes, cylinders, and beams were cast with various mix proportions replacing 0-30% of cement with metakaolin and 1.5-4.5% with nano-silica. The specimens were tested after 7 and 28 days of curing to determine their compressive, tensile, and flexural strengths. The results showed that partial replacements of cement with metakaolin and nano-silica can improve the strength characteristics of concrete.
Effect of vinsuperplast on the hydration study of rice husk ash blended cementeSAT Journals
1) The document discusses a study on the effect of Vinsuperplast superplasticizer on the hydration of rice husk ash blended cement.
2) Experiments were conducted to measure consistency, setting time, non-evaporable water content, free lime, and strength of cement with various rice husk ash and superplasticizer contents.
3) The results showed that addition of 2% superplasticizer increased hydration and strength by reducing water demand and increasing fluidity through electrostatic repulsion between cement particles.
Similar to Investigation on the effect of slag and limestone (20)
Hudhud cyclone caused extensive damage in Visakhapatnam, India in October 2014, especially to tree cover. This will likely impact the local environment in several ways: increased air pollution as trees absorb less; higher temperatures without tree canopy; increased erosion and landslides. It also created large amounts of waste from destroyed trees. Proper management of solid waste is needed to prevent disease spread. Suggested measures include restoring damaged plants, building fountains to reduce heat, mandating light-colored buildings, improving waste management, and educating public on health risks. Overall, changes are needed to water, land, and waste practices to rebuild the environment after the cyclone removed green cover.
Impact of flood disaster in a drought prone area – case study of alampur vill...eSAT Publishing House
1) In September-October 2009, unprecedented heavy rainfall and dam releases caused widespread flooding in Alampur village in Mahabub Nagar district, a historically drought-prone area.
2) The flood damaged or destroyed homes, buildings, infrastructure, crops, and documents. It displaced many residents and cut off the village.
3) The socioeconomic conditions and mud-based construction of homes in the village exacerbated the flood's impacts, making damage more severe and recovery more difficult.
The document summarizes the Hudhud cyclone that struck Visakhapatnam, India in October 2014. It describes the cyclone's formation, rapid intensification to winds of 175 km/h, and landfall near Visakhapatnam. The cyclone caused extensive damage estimated at over $1 billion and at least 109 deaths in India and Nepal. Infrastructure like buildings, bridges, and power lines were destroyed. Crops and fishing boats were also damaged. The document then discusses coping strategies and improvements needed to disaster management plans to better prepare for future cyclones.
Groundwater investigation using geophysical methods a case study of pydibhim...eSAT Publishing House
This document summarizes the results of a geophysical investigation using vertical electrical sounding (VES) methods at 13 locations around an industrial area in India. The VES data was interpreted to generate geo-electric sections and pseudo-sections showing subsurface resistivity variations. Three main layers were typically identified - a high resistivity topsoil, a weathered middle layer, and a basement rock. Pseudo-sections revealed relatively more weathered areas in the northwest and southwest. Resistivity sections helped identify zones of possible high groundwater potential based on low resistivity anomalies sandwiched between more resistive layers. The study concluded the electrical resistivity method was useful for understanding subsurface geology and identifying areas prospective for groundwater exploration.
Flood related disasters concerned to urban flooding in bangalore, indiaeSAT Publishing House
1. The document discusses urban flooding in Bangalore, India. It describes how factors like heavy rainfall, population growth, and improper land use have contributed to increased flooding in the city.
2. Flooding events in 2013 are analyzed in detail. A November rainfall caused runoff six times higher than the drainage capacity, inundating low-lying residential areas.
3. Impacts of urban flooding include disrupted daily life, damaged infrastructure, and decreased economic activity in affected areas. The document calls for improved flood management strategies to better mitigate urban flooding risks in Bangalore.
Enhancing post disaster recovery by optimal infrastructure capacity buildingeSAT Publishing House
This document discusses enhancing post-disaster recovery through optimal infrastructure capacity building. It presents a model to minimize the cost of meeting demand using auxiliary capacities when disaster damages infrastructure. The model uses genetic algorithms to select optimal capacity combinations. The document reviews how infrastructure provides vital services supporting recovery activities and discusses classifying infrastructure into six types. When disaster reduces infrastructure services, a gap forms between community demands and available support, hindering recovery. The proposed research aims to identify this gap and optimize capacity selection to fill it cost-effectively.
Effect of lintel and lintel band on the global performance of reinforced conc...eSAT Publishing House
This document analyzes the effect of lintels and lintel bands on the seismic performance of reinforced concrete masonry infilled frames through non-linear static pushover analysis. Four frame models are considered: a frame with a full masonry infill wall; a frame with a central opening but no lintel/band; a frame with a lintel above the opening; and a frame with a lintel band above the opening. The results show that the full infill wall model has 27% higher stiffness and 32% higher strength than the model with just an opening. Models with lintels or lintel bands have slightly higher strength and stiffness than the model with just an opening. The document concludes lintels and lintel
Wind damage to trees in the gitam university campus at visakhapatnam by cyclo...eSAT Publishing House
1) A cyclone with wind speeds of 175-200 kph caused massive damage to the green cover of Gitam University campus in Visakhapatnam, India. Thousands of trees were uprooted or damaged.
2) A study assessed different types of damage to trees from the cyclone, including defoliation, salt spray damage, damage to stems/branches, and uprooting. Certain tree species were more vulnerable than others.
3) The results of the study can help in selecting more wind-resistant tree species for future planting and reducing damage from future storms.
Wind damage to buildings, infrastrucuture and landscape elements along the be...eSAT Publishing House
1) A visual study was conducted to assess wind damage from Cyclone Hudhud along the 27km Visakha-Bheemli Beach road in Visakhapatnam, India.
2) Residential and commercial buildings suffered extensive roof damage, while glass facades on hotels and restaurants were shattered. Infrastructure like electricity poles and bus shelters were destroyed.
3) Landscape elements faced damage, including collapsed trees that damaged pavements, and debris in parks. The cyclone wiped out over half the city's green cover and caused beach erosion around protected areas.
1) The document reviews factors that influence the shear strength of reinforced concrete deep beams, including compressive strength of concrete, percentage of tension reinforcement, vertical and horizontal web reinforcement, aggregate interlock, shear span-to-depth ratio, loading distribution, side cover, and beam depth.
2) It finds that compressive strength of concrete, tension reinforcement percentage, and web reinforcement all increase shear strength, while shear strength decreases as shear span-to-depth ratio increases.
3) The distribution and amount of vertical and horizontal web reinforcement also affects shear strength, but closely spaced stirrups do not necessarily enhance capacity or performance.
Role of voluntary teams of professional engineers in dissater management – ex...eSAT Publishing House
1) A team of 17 professional engineers from various disciplines called the "Griha Seva" team volunteered after the 2001 Gujarat earthquake to provide technical assistance.
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1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 123
INVESTIGATION ON THE EFFECT OF SLAG AND LIMESTONE
POWDER ADDITION IN ALKALI ACTIVATED METAKAOLIN
X. Gao1
, Q.L. Yu2
, R. Yu3
, H.J.H. Brouwers4
, Z.H. Shui5
1
Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, the
Netherlands
2
Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, the
Netherlands
3
Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, the
Netherlands
4
Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, the
Netherlands
5
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan Hubei 430070,
China
Abstract
Alkali activated material has recently attracted great attention as an environmentally friendly building material. Generally, it
exhibits higher mechanical properties and better durability when compared with Portland cement based materials. In this article,
mixed alkali activated systems consisting of N-A-S-H and C-A-S-H hydrated gels were produced, using metakaolin as a dominated
starting material and granulated blast furnace slag as an additional calcium and silicate source. Limestone powder was then added
into the blended metakaolin-slag system as a filler. The influences of slag and limestone powder on setting times, strength
development and microstructure were analyzed. The results indicate that, with the increasing slag content, the setting time
decreases; the compressive strength firstly increases and then decreases after the slag replacement exceeds a critical value.
Additionally, an optimum content for limestone powder in the metakaolin-slag blends is around 15%. The FTIR spectra and XRD
pattern present the changes in reaction products when slag was added, and the scanning electron microscope results showed a
denser matrix of the geopolymeric system when compared to reference sample. However, no significant changes of reaction
products were detected when limestone powder was incorporated, which indicates that the limestone powder only works as a non-
reactive phase in the alkali activated system.
Keywords: Alkali activation, Metakaolin, Slag, Limestone powder
---------------------------------------------------------------------***-------------------------------------------------------------------
1. INTRODUCTION
The production of Portland cement is now responsible for
nearly 7% of the total CO2 emission around the world [1],
other accompanied negative impacts of cement industry are
the consumption of natural resources and high energy cost.
Thus it is urgent to find approaches to reduce the
environmental impacts of cement industry. Among those
studies of finding alternatives to ordinary Portland cement,
alkali activated materials have attracted great attention in
recent years mainly due to their high mechanical properties,
low environmental and energy consumptions [2,3]. Also
other excellent properties are reported such as low heat
resolution during hydration, fast early strength development,
good durability related properties and thermal stability [4-7].
Raw materials used in producing alkali activated binders are
usually industrial wastes, other than ordinary Portland
cement, thus a promising future of sustainable development
can be seen from this new clinker free building material.
Alkali activated materials are usually produced by mixing
alkaline activator solutions with solid raw materials. The
hydration process is called geopolymerization, which
contains a series of chemical reactions including the
dissolution of starting materials, polycondensation,
condensation and finally the crystallization of new reaction
products [8]. Final products can be classified into two types
according to different raw material chemistry, for silicate and
aluminum enriched precursors like metakaolin or fly ash,
final products are amorphous alkaline aluminosilicate
hydrate gels with a three-dimensional network of aluminate
and silicate units that are charge balanced by alkali cations,
or can be simply described as N-A-S-H type gel [9]; for
calcium and silicate enriched ones like granulated blast
furnace slag, final products are aluminium substituted C-S-H
(I) type gel with lower Ca/Si ratio [10]. Sodium hydroxide
modified sodium silicate has been widely accepted as an
ideal activator in terms of strength and other beneficial
properties, the alkaline activator type and dosage have a
significant influence on the reaction process and
comprehensive properties of the final products [11]. Other
important factors are curing conditions such as temperature,
time, relative humidity and physicochemical properties of the
starting materials such as mineralogical composition and
fineness [12].
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Commonly alkali activated materials based on Si and Al type
have excellent mechanical properties, enhanced
reinforcement steel bonding and fire resistance, but at the
same time, drawbacks such as long setting time and slow
strength development, high requirement of curing are
obstacles to their practical application. Several researchers
have found that adding slag into Si and Al based geopolymer
can improve the compressive strength and decrease the
setting time to some degree, also acceptable strength can be
achieved [13,14]. Calcium component in slag is responsible
for the decrease of setting, the stable coexistence of
aluminum substituted C-S-H gel and the N-A-S-H gel
contributes to the improvements in terms of strength,
permeability and durability [15]. Besides, only a few work
focuses on the utilization of limestone powder as additives in
alkali activated systems. Limestone has already been used in
Portland cement system successfully, the already known
influences are improving workability and strength by the
filler effect, accelerating the hydration process by the nuclear
effect, also lowering the price and energy cost of the overall
system. Thus there could be some potential benefits of using
limestone in alkali activated systems such as modifying
workability, strength, cost and environmental impact. The
aims of this paper are to investigate the influences of slag on
setting, strength and phase changes on alkali activated
metakaolin, also to study the effects of limestone powder on
metakaolin-slag blends.
2. EXPERIMENTAL PROGRAM
2.1 Materials
The metakaolin was produced in the laboratory by
calcination of kaolinite under 750 o
C for 4 hours. The
kaolinite containing small amount of quartz and illite as
impurities, mineral composition are shown in Table 1, with a
specific surface area of 2230 m2
/kg and more than 90% of
particles are finer than 2 µm. The granulated blast furnace
slag used has a specific surface area of 490 m2
/kg and a
specific density of 2.70 g/cm3
. Limestone powder with a
D(0.5) of 5 µm and specific surface area of 1100 m2
/kg was
used. The major chemical compositions of metakaolin, slag
and limestone powder are given in Table 2.
Table 1: Mineral compositions of kaolinite
Mineral Kaolinite Quartz Illite
% 91.91 1.6 6.49
Table 2: Major compositions of raw materials (%)
Oxides Metakaolin Slag Limestone
CaO 0 38.06 53.42
SiO2 54.46 34.14 0.61
Al2O3 39.86 10.34 0.49
MgO 0 7.95 1.62
Fe2O3 1.98 0.38 0.21
LOI 2.01 0.03 43.15
2.2 Mix Design and Sample Preparation
Samples were prepared by firstly mixing NaOH with sodium
silicate solutions and then cooling it down to room
temperature, then blending the liquid activator with the raw
material in the mixer. Slag was added from 0% to 40% with
a range of 10% by mass to study the influences of slag
addition on setting, strength and reaction products of alkali
activated metakaolin. For each sample, sodium hydroxide
and sodium silicate were used with the fixed total SiO2/Al2O3
ratio of 4.0 and Na2O/Al2O3 ratio of 1.0. Based on the alkali
activated metakaolin-slag mixes with ideal property,
limestone powder was added from 0% to 20% by mass of the
total binder to analyze its effects on strength and reaction
products of the blended system. A overall water/binder ratio
of 0.37 was used for all mixes, while the total water includes
the free water and water in activator solution, and the total
binder was defined as raw materials and the solid phase in
activator. All mixes were cured at 25 ± 2 o
C with a relative
humidity of 90% until the testing age.
2.3 Testing Methods
The setting times of the alkali activated pastes were tested
using the Vicat needle method in accordance with the
Chinese national standard GB/T 1346-2011. The
compressive strength testing were carried out according to
the Chinese national standard GB/T 17671-2005. The
samples were tested after 7 and 28 days curing, the strength
values for each sample was obtained from the average of
three mixes. The X-ray diffraction was conducted using a
CoKα radiation over the 2θ range from 5° to 70°, a fourier
transform infrared spectroscopy measurement with the
wavenumbers ranging from 4000 to 400 cm-1
is performed to
investigate the reaction products. All powder samples for
XRD and FTIR analysis were prepared by mechanical
grinding and tested after 28d of curing. The microstructural
characters of different mixes were investigated by a scanning
electron microscope.
3. RESULTS AND DISCUSSIONS
3.1 Setting Times
The setting times of alkali activated metakaolin pastes with
the slag replacement up to 40% are shown in Table 3. It can
be seen that as the slag content increases, both the initial and
final setting times decrease significantly. The initial setting
time of the neat metakaolin sample was 155 mins, while as
the slag replacement reached 40%, the initial setting
decreased nearly three times to 45 mins. Similar results
happened to the final setting time. It seems that the
remarkable reduction of setting times was caused by the
calcium in the slag. The structure of metakaolin is dominated
by silicate and aluminum oxide compounds, the Al-O and Si-
O bonds in metakaolin are relatively difficult to be activated
due to the nature of the original clay-type structure, thus the
initial and final setting times were relatively long. On the
other hand, because of the presence of calcium in the
molecular structure, the glassy phase of slag is more
disordered, thus it is more vulnerable to breakdown under
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 125
alkali activation. Finally, the fast release of calcium in
solution lead to the reduced setting time.
Table 3: Setting times of metakaolin-slag blends
Metakaolin
(%)
Slag
(%)
Initial setting
(min)
Final setting
(min)
100 0 155 240
90 10 105 215
80 20 70 165
70 30 55 130
60 40 45 115
3.2 Strength Development
Figure 1 presents the 7d and 28d compressive strength
results of alkali activated metakaolin with slag replacement
from 0% to 40%, which shows that as the slag content
increases, the compressive strength firstly increases and
reaches the highest value at the slag content of 20%, then
leads to a reduction of the compressive strength. All samples
have a 7d strength of more than 58 MPa and 28d strength of
more than 60 MPa, and the highest strength reaches 72.5
MPa with 20% slag replacement by weight. Also, the
strength development from 7d to 28d becomes more
significant as the increase of slag content.
Fig. 1: Compressive strength of metakaolin-slag mixes
The increase in compressive strength when slag was added is
attributed to the presence of the calcium in the slag and the
accompanied formation of calcium enriched hydrated C-A-S-
H type gel is widely accepted as an gel that characterized of
high strength [16]. The formation of small amount of C-A-S-
H gel helped to refine the microstructure of N-A-S-H gel
(main hydration products of metakaolin) and generated more
crosslinking within the reaction product [17], then resulted in
an increase in compressive strength. The decreased strength
when higher slag was added indicates that there may exist an
ideal balance between the activator character and the raw
materials.
Metakaolin and slag mixes that with the highest compressive
strength results (80% metakaolin and 20% slag in this case)
were chosen and incorporated with limestone powder to
study its effect on compressive strength of alkali activated
metakaolin and slag blends, and the results are shown in Fig.
2. All samples show similar compressive strength values
after 7d curing except the one with 20% limestone content.
The 28d compressive strength stably increases as the
limestone content increases, the highest strength is obtained
with a limestone content of 15%, the further higher content
leads to a considerable reduction of compressive strength.
This reveals that the addition of limestone powder has
limited influence on the early strength but could slightly
increase the strength at longer ages within the range of
optimum content. Higher content of limestone powder may
have detrimental effects on the structure of hydrated gels and
then lead to the decrease of compressive strength.
Fig. 2: Effect of limestone powder on metakaolin-slag mixes
3.3 FTIR Spectra Analysis
Figure 3 shows the fourier transform infrared spectra of
alkali activated metakaolin paste samples after 28 days
curing with slag contents of 0%, 20% and 40%. The main
absorption bands are listed in Table 4. The major absorption
band is around 1000 cm-1
, which is assigned to the
asymmetric stretching vibration of the Si-O-T (T=Si or Al)
bonds [18], a typical vibration band of N-A-S-H type gel
from metakaolin. The presence of this band also indicates the
polymerization process took place. With the incorporation of
slag, the wavenumber of this band decreased. Generally, the
reduction of wavenumber indicates the decrease of
polymerization degree of the reaction products. Thus here it
means the addition of slag into metakaolin reduced the
polymerization degree of the hydrated gels to some extent,
therefore the structure of the hydrated N-A-S-H gel was
changed into a lower polymerization one by the presence of
calcium from slag. It proves that the addition of slag indeed
has some influences on the final hydrated product of
metakaolin. Other significant wavenumber changes also
reveal the structure of reaction products has been altered by
the addition of slag, such as the bending vibration of T(IV)-
O at around 570 cm-1
disappeared as the slag was added and
the T-O asymmetric stretching vibration bonds around 1400
0
10
20
30
40
50
60
70
80
90
0% 10% 20% 30% 40%
Compressivestrength(MPa)
Slag replacement
7d 28d 0
10
20
30
40
50
60
70
80
90
0% 5% 10% 15% 20%
Compressivestrength(MPa)
Limestone content
7d 28d
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 126
cm-1
increased at the beginning and then disappeared as the
increase of slag content.
Fig. 3: FTIR spectra of metakaolin-slag blends
Table 4: Corresponding bands of metakaolin-slag blends
Absorption
bands
100 MK
0 GGBS
80 MK
20 GGBS
60 MK
40 GGBS
-OH, H2O 3444 3445 3445
H2O 1645 1647 1647
O-C-O -- -- 1471
T-O 1375 1417 --
Si-O 1015 1001 1000
Al(IV)-O 702 701 700
T(IV)-O 566 -- --
Si-O 444 448 448
The absorption bands at around 3450 cm-1
and 1650 cm-1
are
attributed to the stretching and deformation vibrations of O–
H and H–O–H groups, which present the water bonded in the
reaction products. No significant changes in the bands at
around 700 cm-1
, which represent the vibration of four
coordinated aluminum mainly from metakaolin, showing that
the addition of slag has limited influence on the structure of
AlO4 in the final reaction products. The absorption bands
around 450 cm-1
represent the internal deformation vibrations
of Si-O bonds [19], which is mainly influenced by the nature
of raw materials and thus no remarkable changes take place.
The absorption band around 1470 cm-1
appeared only in the
samples with large slag content, it represents the asymmetric
stretching mode of the O–C–O groups [20], which means the
carbonation has taken place to some extent, it may also
indicate that samples with higher slag content are more
vulnerable to carbonation, but still more study are needed to
confirm this conclusion. The infrared spectra of samples
containing limestone powder are not shown because there are
no significant changes in the major absorption bands when
limestone powder was added, which indicates that the
incorporation of limestone powder has no influence on the
reaction products and it only works as an non-reactive filler
in alkali activated system.
3.4 XRD Analysis
The XRD patterns of alkali activated metakaolin pastes with
0%, 20% and 40% slag replacement are shown in Figure 4.
The main reaction products of all mixes are amorphous
phases except small amount of crystalline phases that
obtained from the raw materials such as quartz and illite. The
major hump area for neat metakaolin samples are from 20o
to
30o
, which is within the typical range of alkali activated
metakaolin and reveals the formation of hydrated N-A-S-H
type gels from metakaolin. The amorphous phases with
humps ranging from 20o
to 30o
can be regarded as the result
of the geopolymerization progress of metakaolin.
Fig. 4: XRD spectra of metakaolin-slag blends
As the slag content increases, the main hump area gradually
moves to higher degree, which is in coordiance with the
FTIR results and reveals the phase changes in reaction
products caused by slag addition. As the slag content
continues to increase, the intensity peaks at around 30o
appeares, which represents the formation of an C-S-H type
gel from alkali activated slag. The intensity peaks that
represent C-S-H gel becomes more significant in samples
with higher slag content. Combined with the results from
FTIR, the available calcium in the solution caused by the
addition of slag seems to have significant influences on the
reaction products of silicate and aluminum dominated alkali
activated metakaolin, causing the formation of reaction
products other than N-A-S-H and changing the original N-A-
S-H gel structure to some extent such as a lower
polymerization degree and changing the major hump areas.
The XRD patterns with limestone powder incorporation are
not shown because as the limestone content increases in the
metakaolin and slag mixes, no changes take place in the
original hump areas and intensity peaks, the intensity peaks
of limestone still remain unchanged, which combined with
the FTIR result reveals again that the limestone powder
seems to work as only a filler in the alkali activated system.
400 1400 2400 3400
Wavenumbers(cm-1)
60
80
MK
100
MK
10 20 30 40 50
2 Theta
100MK
80MK+20GGB
S
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Volume: 03 Special Issue: 13 | ICNTCC-2014 | Sep-2014, Available @ http://www.ijret.org 127
3.5 SEM Analysis
The SEM images of the 28d alkali activated metakaolin paste
samples containing 0% and 20% slag are shown in Figure 5.
The left and right column represents the neat metakaolin
sample and samples containing 20% slag, respectively.
AA-MK AA-MK/GGBS
Fig. 5: SEM images of metakaolin with/without slag
addition
It can be seen that even though neat alkali activated
metakaolin samples have acceptable 28d compressive
strength of around 60 MPa, some remarkable pores are still
remaining under high magnifications. The reaction products
exhibit layered structure in short ranges and disordered in
longer ranges. The failure of samples in compressive
strength test also showed layered structure, it seems that the
nature of clay-type structure of metakaolin should be
responsible for the failure. When a suitable content of slag
was added, pores between the layers of alkali activated
metakaolin were condensed by the hydrated slags. Also, the
addition of slag provides calcium and leads to the formation
of C-S-H type gel, which is characterized by a high strength,
linked together with the original N-A-S-H gel, then
contributes to the refinement of microstructure and improves
the compressive strength.
4. CONCLUSION
The incorporation of slag significantly reduced the initial and
final setting times of alkali activated metakaolin, and the
setting times continually decreased as the increase of the slag
content. The compressive strength firstly increased and then
decreased as the slag content increased, and the optimum
slag content in this case is 20%, similar results were obtained
in limestone powder addition into metakaolin-slag blends
and the optimum limestone powder content is around 15%.
Both the XRD and FTIR results show significant changes in
reaction products as a result of slag incorporation. Both N-A-
S-H from metakaolin and C-S-H type gel from slag were
detected, the addition of slag induced some changes of the
original N-A-S-H gel structure such as the polymerization
degree and the disappearance of some typical vibration
bonds. Limestone powder seemed to work as an non-reactive
filler in the alkali activated system since no significant
changes were detected in both XRD and FTIR analysis. The
microstructure analysis showed that the original alkali
activated metakaolin paste was modified by the addition of
slag, resulting in a denser matrix and resulted in an improved
compressive strength.
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BIOGRAPHIES
Xu Gao, has received his Master’s degree from Wuhan
University of Technology, China. Currently working as a
Ph.D. student in the Department of the Built Environment,
Eindhoven University of Technology, the Netherlands. His
research interests include the modification, modeling and
application of alkali activated mateirals.
Qingliang Yu, received his Ph.D. degree from Eindhoven
University of Technology, the Netherlands. He is currently
working as an assistant professor in the Department of the
Built Environment, Eindhoven University of Technology.
His research interests include lightweight aggregate concrete,
air purring functional concrete and gypsum based concrete.
Rui Yu, has received his masters from Wuhan University of
Technology, China. Currently achieving an Ph.D. degree in
the department of the Built Environment, Eindhoven
University of Technology, the Netherlands. His research
interests include the ultra-high performance concrete and
fiber reinforced concrete.
H.J.H. Brouwers, is professor Building Materials and head
of the unit Building Physics & Services at Eindhoven
University of Technology.
Zhonghe Shui, has received his Ph.D. degree in 2001 from
Delft University of Technology, The Netherlands. He is
currently working in Wuhan University of Technology,
China as a full professor in the Department of Material
Science.