Strength Of Geopolymer Concrete Research Articles

Experimental investigation on bond behaviour of the GFRP bars with normal and high strength geopolymer concrete

The study presents the experimental investigation of bond performance of normal and high-strength geopolymer concrete and Glass Fibre Reinforced Polymer (GFRP) bars. The effects of bar diameters, embedment lengths, and concrete grades on maximum pullout load and failure characteristics are investigated. When the adhesive and residual strengths of GFRP bond specimens were compared to steel specimens, the former demonstrated remarkable performance despite having differing surface properties. An energy-based equivalent bond strength approach is proposed to examine pre-peak bond performance, which demonstrating that the decreasing rate of strength is faster for higher diameter and embedment, showing a drop in bond performance. Pullout failure was noted in smaller diameter bond specimens, where the shear strength between the ribs and the GFRP bar controlled the bond strength. Concrete split failure occurs for 12 mm specimens with embedment lengths greater than 5d in both GPC40 and GPC60. Specimens with 16 mm, excluding G-16-5d-60, demonstrated concrete split failure for all embedment lengths and concrete grades; bond strength is determined by the concrete shear strength. Enhancing the concrete’s compressive strength has a beneficial impact on the bond strength as it increases ranging, from 14.57 to 32.12%. Analytical models such as mBPE and CMR were employed to derive the mathematical expression for the bond stress versus slip curve. It was found that the curves of CMR model were typically closer to experimental curves than the mBPE model.

Mechanical and durability properties of standard and high strength geopolymer concrete using particle packing theory

Aggregate packing significantly affects the characteristics of fresh and hardened concrete; aggregates having higher packing density (PD) improve these characteristics. There is a lack of research on how the PD affects the properties of geopolymer concrete (GPC). Hence, the present study includes the effect of the PD on the mechanical and durability properties of the standard and high-strength GPC. The study parameters are the binder content, the concentration of NaOH, and the fly ash to ground granulated blast furnace slag (GGBS) ratio. Six aggregate groups (like 12.5–10 mm, 10–4.75 mm, 4.75–2.36 mm, 2.36-1.18 mm, 1.18–0.6, and 0.6–0.15 mm) were investigated for the particle packing experiment, and the blended coarse:fine aggregate ratio of 55:45 which produced the highest packing density of 0.702, were used in the GPC mixes. A total of 120 cubes of size 100 mm, 30 cylinders of size 100 × 200 mm, and 30 prisms of size 100 × 100 × 500 mm were cast for 10 different mixes in the study. Sorptivity and water absorption are the tests performed for the durability studies. The result shows that GPC mixes with Particle packing theory significantly improved the compressive strength, and durability, and showed better workability. The workability of the GPC reduces by increasing the GGBS and concentration of the NaOH solution. As the GGBS proportion and the concentration of the NaOH solution increases, the concrete compressive, split, and flexural strength increases. As the binder content increases, the strength increases at first, then reduces. Increasing the GGBS content, binder content, and molarity of the NaOH accomplishes a reduction of the sorptivity coefficient and water absorption of the GPC.

A state-of-the-art review on the mechanical behaviours of GGBFS concrete for sustainable development

Low carbon concretes like geopolymer concrete have been developed as a result of the demand for ecologically friendly and environmentally sustainable concrete for building. Concrete replaced with geopolymer utilizing fly ash and slag as part of its combination, cement made from industrial waste materials the process of geopolymerization only requires a modest amount of alkali activator. There are numerous numbers of studies that have been done based on the mix ratio, workability, material characteristics and strength of geopolymer concrete (GPC) for the previous years. As a result, this review adheres to the GPC that was thoroughly investigated using Preferred Reporting Items for Systematic Reviews (PRISMA). This study's goal is to examine the various geopolymer concrete (GPC) precursors, applications, and contemporary synthetic procedures in addition to the mechanical and physical aspects of GPC made from diverse wastes. The review also goes into great detail about how GPC helps achieve the goals for sustainable development that many experts have put forward. Additionally, it has been stated that the development of a circular economy based on the GPC will offer suggestions and opportunities for GPC research and technology.

Experimental Investigation on Geopolymer Concrete:- Sustainable and Eco-Friendly Construction Material

The research for the new environmental friendly construction material that will match the durability of ancient concrete has provoked interest into the study of alkali activated cementitious systems over the last two decades. It results in the development of Geopolymer Concrete. This paper represents the development of geopolymer mixes of various ratios of fly ash and GGBS and their mechanical properties were studied. aa Literature review on mechanical and durability properties of geopolymer concrete also been done. The ratio of sodium hydroxide to sodium silicate is 1:2 which is kept a constant to prepare the mix and alkaline liquid to binder ratio as 0.70, but changing the concentration of sodium hydroxide solution as 6M, 4M and 3M to prepare the mix Id. i.e. F75G25, F50G50 and F25G75, respectively (where F and G are Fly Ash and GGBS and the numerical value indicates the percentage of replacement of fly ash by GGBS) were prepared in AML laboratory, CSIR-SERC, Chennai. Ambient curing of concrete at room temperature was adopted.The compressive strength at age of 3, 7 and 28 days were determined. The strength of geopolymer concrete was increased with increase in percentage of GGBS in a mix. It was observed that the mix Id F25G75 gave maximum compressive strength for concentration of NaOH as 3M . Leaching of GPC reduces with increase in percentage of GGBS in a mix. Thus the geopolymer concrete have a relatively higher strength.

Performance of geopolymer concrete activated by sodium silicate and silica fume activator

This study examined the properties (strength, workability and crack) of geopolymer concrete activated by sodium silicate and silica fume activator. Sodium silicate and sodium hydroxide (NaOH) are commonly activators used to make geological polymer composite. However, they will cause the decline of the performance of geopolymer concrete when it is prone to polymerization in the surrounding of alkaline. Silica fume can improve the workability and strength of geopolymer concrete. The Pearson correlation coefficient and experiment is used to study the performance of geopolymer concrete with sodium silicate and silica fume activator. The influence of two kinds of activators on the slump of geopolymers with different mix ratios was analyzed by Pearson correlation coefficient. The relative coefficient of mineral powder decreased from 0.785 to 0.409. The absolute relative coefficient of calcined magnesite decreased from 0.829 to 0.156. The correlation between slag, calcined magnesite and slump changed from significant to insignificant. The analysis shows that the slump of geopolymers with silica fume activator are less affected by mineral powder and calcined magnesite than that of sodium silicate activator. Geopolymer concrete have more stable performance with silica fume activator. The geopolymer concrete excited by silica fume activator compared with the sodium silicate activator, the cracks and internal porosities on the surface of the specimens are less. The compressive strength and crack of geopolymer concrete excited by silica fume activator reached 43.36 MPa and 0.095 mm, respectively, at 20 ℃ ± 2 ℃ and more than 95% humidity. It shows good early strength and less cracks. The experimental mix proportions are optimized to conduct the complex the equilibrium of physical and chemical reactions and to reinforce the mechanical property of geopolymer concrete with silicate fume activator.

Performance evaluation on engineering properties and sustainability analysis of high strength geopolymer concrete

This research presents an investigation that aims to optimize the mix proportion of the High Strength Alkali Activated Concrete (HSAAC) developed using the Taguchi Method (TM). Since Alkali Activated Concrete (AAC) contains a wide range of mix ingredients than conventional cement-based concrete, several trials are required to optimize the strength requirement of HSAAC. In this paper, the influence of binder (slag content), the concentration of sodium hydroxide, alkaline activator (AA) ratio, and curing condition on the strength of HSAAC is discussed. Eighteen trial mixes were designed based on the Taguchi analysis and evaluated experimentally. Based on the analysis of the results from TM, the mix design of HSAAC is evaluated. The experimental investigation on mechanical properties such as compressive, tensile, and flexural strengths of HSAAC is carried out. In addition to the mechanical properties, the workability of HSAAC is evaluated. The study reports that with the binder content of 500 kg/m3, AA ratio of 2, Activator to Binder (A/B) ratio of 0.5, and 12 M concentration of sodium hydroxide under ambient curing conditions attains the maximum compressive strength of 63.37 MPa. In addition, the sustainability performance of HSAAC in terms of cost-efficiency, carbon efficiency, and energy efficiency was evaluated and compared with the existing conventional cement-based concrete.

Flexural behavior evaluation of repaired high strength geopolymer concrete

CO2 is released during the manufacture of ordinary Portland cement (OPC). The utilization of wastes and byproducts in concrete can lead to new sustainable constructions. To replace OPC in high-strength Portland cement concrete (HSPC), ground granulated blast furnace slag (GGBS) is utilized. GGBS is a by-product of the blast furnace used for iron manufacturing. It has a high silicate gel content and is used to produce good concrete. This paper investigates the load-deformation behavior of high-strength reinforced geopolymer concrete (HSGC) beams that were tested in flexure after being repaired. Six beams were placed using HSGC and HSPC. The original beams were tested, and deflections were measured. Specimens were tested under static stresses, then repaired with epoxy resin injection and re-tested for flexural strength. For both the original and repaired beams, load versus deflection graphs were recorded. Maximum deflection, ultimate load, cracking load, and crack pattern were all determined. The findings suggest that the restored HSGC beams' strength is equivalent to that of the original beams. The strength of the beam has been recovered. The cracks do not re-open after retesting, instead, new nearby cracks developed. The repaired beams showed superior flexural behavior and greater ductility than the original beams.

Comparative Study on Strength Characteristics of Fly Ash Based Geopolymer Concrete with 8, 10 & 12 Molar Naoh Activator

Ordinary Portland cement is a major construction material worldwide. Cement manufacturing industry is one of the carbon dioxides emitting sources besides deforestation and burning of fossil fuels. The global warming is caused by the emission of greenhouse gases, such as CO2, to the atmosphere. Among the greenhouse gases, CO2 contributes about 65% of global warming. The cement sector accounts for around 7% of worldwide greenhouse gas emissions of the earth’s atmosphere. In order to address environmental effects associated with Portland cement, Alternative binders for concrete production are needed. Low-calcium (Class F) fly ash-based geopolymer from Vijayawada was used in this study. Geopolymer concrete was made with the help of a thermal power plant. The combination of sodium silicate solution and sodium hydroxide solution was used as alkaline solution for fly ash activation. Alkaline solution to fly ash ratio was varied as 0.45. The concentration of sodium hydroxide solution was maintained as 8M, 10M & 12M (Molars). The curing condition of geopolymer concrete was varied as ambient curing. The compressive strength, Split Tensile Strength of the geopolymer concrete was tested at various ages such as 7 and 28days. From the test results it was found that as the alkaline solution to fly ash ratio increases, the strength of geopolymer concrete also increases.

Experimental Study of Using Rice Husk Ash and Borax on The Compressive Strength of Geopolymer Concrete

The development of infrastructure in Indonesia is currently very increasing, The use of concrete is widely used to build dams, buildings, roads, bridges and others. Concrete is used because it has advantages over other materials, apart from having compressive strength, concrete is also a relatively inexpensive material. However, the increasing amount of cement used in the manufacture of concrete will cause an increase in global warming. Thus, geopolymer concrete was introduced as an alternative to reduce cement consumption in concrete work. The purpose of this study was to determine the effect of using rice husk ash and borax as an alternative material on the compressive strength of concrete and to determine the effect of using rice husk ash and borax as an alternative material to slow the setting time of geopolymer concrete. The variations in the use of rice husk ash 0%, 10%, 15%, and 20% with the use of 3% borax. From the results of the study, the use of rice husk ash and borax in the geopolymer concrete mixture had an effect on the compressive strength of concrete in this study, with the addition of rice husk ash there was a decrease in compressive strength when compared to normal geopolymer concrete or without a mixture of rice husk ash and borax. The use of 15% rice husk ash and 3% borax achieved the highest compressive strength values when compared to the use of rice husk ash as much as 10% and 20%. Furthermore, the more the use of rice husk ash with the use of 3% borax, the longer the setting time in geopolymer concrete.

Effect of superplasticizer on the strength of fly ash based geopolymer concrete

In this research, the effect of a polycarboxylate based superplasticizer on the strength of Geopolymer Concrete (GPC) was investigated. A fixed amount of superplasticizer (1.5 % of Fly Ash weight) was utilized along with alkali activators Sodium Hydroxide (NaOH) and Sodium Silicate (Na2SiO3). The Ultrasonic Pulse Velocity Test determined the strength development of concrete. The quality of the GPC improved when a higher concentration of alkali activator was applied based on the Concrete Quality Designation. In detecting the color development of GPC, samples were put through MATLAB and specimens became lighter as time passes due to dehydration (a process where water escapes from the sample). Stress strain diagrams were generated which generally indicate that GPC specimens are ductile. The researchers were able to assess the workability of the mix designs using a rating from 1 to 5, with 1 being the least workable and 5 being the most workable.

Behavior evaluation of sustainable high strength geopolymer concrete based on fly ash, metakaolin, and slag

The environmental challenge such as high energy demand, consuming raw materials, large CO2 emissions, and many other reasons associated with ordinary Portland cement manufacturing-led us to search for alternatives such as green concrete or geopolymer concrete. In this paper industrial wastes like fly ash, metakaolin, and granulated blast furnace slag were used as a base for high strength geopolymer concrete (HSGC). Four high strength concrete (HSC) mixes with Portland cement were produced for comparison with fifteen different geopolymer concrete mixes. All mixes were cast, cured, and tested. Slump and air content were measured as fresh properties for both HSC and HSGC mixes. Compressive strength at 3, 7, 28, and 91 days, splitting tensile strength, flexural strength, and modulus of elasticity were also measured and analyzed as mechanical properties. Durability properties like water permeability coefficient, drying shrinkage at 3, 7, 14, 21, 28, 56, and 91 days and temperature studies from 100 ° to 700 ° were investigated. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy analysis of cement and geopolymer concrete mixes were conducted. Regarding fresh properties results showed that the geopolymer concrete based on slag with 500 kg/m3 showed 225 mm slump, while in hardened properties, the mix contained 200 kg of metakaolin with 300 kg of slag had the greatest compressive strength in both early and late age 63.3, 82.6 MPa, respectively, also had the greatest splitting tensile strength 6.2 MPa, flexural strength reached 9.2 MPa and modulus of elasticity was 37.68 GPa. Also, the coefficient of permeability decreases as the granulated blast furnace slag increases. The mineral additives contributed to reducing the dry shrinkage of geopolymer concrete. SEM images exhibited that the geopolymer matrix contained more dispersed small-sized pores which indicate a higher compressive strength absolutely than other experimental mixes.

Mechanical Properties Prediction of Normal and High Strength Geopolymer Concrete

The production process of cement is the main binder material in concrete usually accompanied by carbon dioxide emission. Therefore, geopolymer concrete (GPC) an alternative binder material was developed as a replacement for cement. In order to make this promising material more common in constructions and applicable for different design purposes further investigations for GPC mechanical properties were needed. This work aims to predicate the splitting tensile strength, modulus of elasticity and flexural strength for normal and high strength GPC by deriving new equations covering a wide range of compressive strength based on data available from previous work. Equations behavior along the changes in compressive strength from normal to high is adopted in comparisons as illustrated. The results show that the proposed equations, as compared with other equations established by previous works, provide a steady behavior for the various values of compressive strength especially for high strength. The coefficient of variation (COV) used as additional comparison criteria, and shows that the proposed equations provide better estimation of GPC mechanical properties.

Partial replacement of fine aggregate with Copper slag and marble dust powder in geo-polymer concrete: A review

-As of late the ascent of substantial creation costs has consistently been a worry of substantial makers and customers. Using current waste to override concrete and some poIn ongoing years the ascent of substantial creation costs has consistently been a worry of substantial makers and buyers. Using present day waste to override concrete and some bit of all out can diminish its cost and environmental dirt of all out can decrease its cost and natural tainting. The mark to the purpose of this paper to audit the shot at powder made from marble dust close by the copper slag as an in part substitution to fine aggregate all out in geo-polymer concrete. Marble dust powder was used in mix in comprise copper slag as in part substitution to fine aggregate in level of 10%, 20%, 30%, 40% and 50%. The strength of geo-polymer concrete was tested after 7 & 28 days. Result shows that compressive strength is increased after the replacement of 60% of copper slag and marble dust powder to fine aggregate and also flexural strength and split tensile strength increases strength upto 60% and 80% after replacement. These discoveries of the examination express that powdered marble dust will be utilized as the conceivable substitution material to fine aggregate to give maximum strength copper slag geo-polymer concrete.

Ultra high performance and high strength geopolymer concrete

Ultra high performance and high strength geopolymer concrete

Mechanical and Microstructural Properties of Copper Slag Based Blended Geopolymer Concrete

This work presents a novel way to examine the characteristics of fly ash, copper slag (CPS) along with the addition of Ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS) based Geopolymer Concrete (GPC) for various molarities (10M, 12M and 14M). In GPC, fly ash was replaced with UFGGBFS (5 %, 10 % and 15 %) and copper slag was used as fine aggregate. Mechanical Characterization such as split tensile, flexural strength, workability and water absorption were conducted . GPC characterization and microstructural behaviour was studied by examining X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). From experimental results this study concludes that with a rise in molarity of GPC, along with incorporation of UFGGBFS, improved the performance, densification and strength of GPC.

Analisis Kuat Beton Geopolimer Menggunakan Fly Ash dan Abu Sekam Padi

One of concrete construction development is the use of geopolymer concrete which is environmentally friendly and efficient in regard to energy utilization. In this study, four combinations of fly ash (FA) and rice husk ash (RHA) was used, namely: i) 100% FA and 0% RHA, ii) 75% FA and 25% RHA, iii) 50% FA and 50% RHA, and iv) 25% FA and 75% RHA, with addition of alkaline solution mix of Na2SiO3 and NaOH with a ratio of 5:1 at 7 days, 14 days, and 28 days of concrete age, with cube samples and will be done a compressive strength test of 225 kg/cm2 (28 days of concrete age). This study aims to determine the optimum variation and analyze the compressive strength of geopolymer concrete using FA and RHA with the addition of an alkaline solution of Na2SiO3: NaOH = 5: 1. Results found that the optimum variation was in the geopolymer concrete mix of 100% FA and 0% RHA with a compressive strength value of 395.643 kg/cm2 (28 days of concrete age), whereas other variations have shown a decrease of compressive strength compare to the normal concrete. Therefore, the geopolymer concrete variation of 100% FA and 0% RHA has a higher compressive strength because the cement substitute used (100% fly ash) contains the right chemical composition in which it can react with alkaline solutions properly. Meanwhile, rice husk ash contains a composition that is not appropriate to be reacted with alkaline solutions. This shows that fly ash is a suitable substitute for cement for geopolymer concrete. In the other hand, rice husk ash is not suitable for use as a substitute for cement in geopolymer concrete.

Sustainable use of fly-ash: Use of gene-expression programming (GEP) and multi-expression programming (MEP) for forecasting the compressive strength geopolymer concrete

Annually, the thermal coal industries produce billion tons of fly-ash (FA) as a waste by-product. Which has been proficiently used for the manufacture of FA based geopolymer concrete (FGC). To accelerate the usage of FA in building industry, an innovative machine learning techniques namely gene expression programming (GEP) and multi expression programming (MEP) are employed for forecasting the compressive strength of FGC. The comprehensive database is constructed comprising of 311 compressive strength results. The obtained equations relate the compressive strength of FGC with eight most effective parameters i.e., curing regime (T), time for curing (t) in hours, age of samples (A) in days, percentage of total aggregate by volume (% Ag), molarity of sodium hydroxide (NaOH) solution (M), silica (SiO2) solids percentage in sodium silicate (Na2SiO3) solution (%S), superplasticizer (%P) and extra water (%EW) as percent FA. The accurateness and predictive capacity of both GEP and MEP model is assessed via statistical checks, external validation criteria suggested by different researcher and then compared with linear regression (LR) and non-linear regression (NLR) models. In comparison with MEP equation, the GEP equation has lesser statistical error and higher correlation coefficient. Also, the GEP equation is short and it would be easy to use in the field. So, the GEP model is further utilized for sensitivity and parametric study. This research will increase the re-usage of hazardous FA in the development of green concrete that would leads to environmental safety and monetarist reliefs.

Predictive modeling of the compressive strength of bacteria-incorporated geopolymer concrete using a gene expression programming approach

The performance of gene expression programming (GEP) in predicting the compressive strength of bacteriaincorporated geopolymer concrete (GPC) was examined in this study. Ground-granulated blast-furnace slag (GGBS), new bacterial strains, fly ash (FA), silica fume (SF), metakaolin (MK), and manufactured sand were used as ingredients in the concrete mixture. For the geopolymer preparation, an 8 M sodium hydroxide (NaOH) solution was used, and the ambient curing temperature (28oC) was maintained for all mixtures. The ratio of sodium silicate (Na2SiO3) to NaOH was 2.33, and the ratio of alkaline liquid to binder was 0.35. Based on experimental data collected from the literature, an evolutionary-based algorithm (GEP) was proposed to develop new predictive models for estimating the compressive strength of GPC containing bacteria. Data were classified into training and testing sets to obtain a closed-form solution using GEP. Independent variables for the model were the constituent materials of GPC, such as FA, MK, SF, and Bacillus bacteria. A total of six GEP formulations were developed for predicting the compressive strength of bacteria-incorporated GPC obtained at 1, 3, 7, 28, 56, and 90 days of curing. 80% and 20% of the data were used for training and testing the models, respectively. R2 values in the range of 0.9747 and 0.9950 (including train and test dataset) were obtained for the concrete samples, which showed that GEP can be used to predict the compressive strength of GPC containing bacteria with minimal error. Moreover, the GEP models were in good agreement with the experimental datasets and were robust and reliable. The models developed could serve as a tool for concrete constructors using geopolymers within the framework of this research.

Effect of pre-treatment methods of crumb rubber on strength, permeability and acid attack resistance of rubberised geopolymer concrete

Concrete industry has been leading to severe energy consumption and is on a path towards unsustainable development. Geopolymer concrete (GPC) uses alternative binders and can be considered a suitable alternative to conventional concrete. On the other hand, huge waste is produced by industries, posing disposal concerns. Rubber waste is a significant waste that can substitute natural aggregate (NA) in concrete. In this study, the effect of replacement of fine aggregates with crumb rubber (CR) on the properties of GPC was investigated. Natural fine aggregates (NFA) were partially replaced by CR with 10, 20, and 30% in volume. The effect of CR pre-treated using different methods such as water, NaOH, cement paste, and ultrafine slag (UFS) on the strength of GPC was examined. The GPC mixes were prepared using 8 M sodium hydroxide (NaOH) and were heat cured at 60°C. The properties of fresh and hardened GPC including, slump, density, compressive strength, flexural strength, splitting tensile strength, and elastic modulus of GPC were investigated. Furthermore, durability characteristics such as water absorption and acid attack resistance were also experimentally examined since an in-depth investigation of durability of GPC incorporating rubber has not been conducted in the previous studies. The experimental results showed that slump, density, and different strengths decreased with an increase in CR%. In contrast to the other batches, the pre-treatment methods with NaOH and UFS improved the properties of GPC. NaOH treatment enhanced the adhesion between CR and other GPC constituents, resulting in a dense matrix structure formation. The formation of calcium silicate products improved the characteristics of GPC when UFS treated CR was utilised. In general, GPC with CR absorbed more water than the reference GPC (without CR) while lower water absorption was observed when pre-treated CR was utilised. GPC with CR also showed poorer resistance to acid attack (HCl and H2SO4).

Compression behavior and modeling of FRP-confined high strength geopolymer concrete

Fiber-reinforced polymer (FRP) has proven its efficiency as a strengthening material of ordinary concrete. However, the research on the effect of these materials on geopolymer concrete is still less understood. Due to the excellent mechanical and environmental properties of geopolymer concrete, the compression behavior of confined high strength geopolymer concrete (HSGC) is experimentally and analytically investigated and compared with high strength cement concrete (HSC). The confined cylindrical test specimens of HSGC and HSC were tested in compression. The cylinders were confined using three schemes of FRP, namely one and two layers of Glass FRP (GFRP) and one layer of carbon FRP (CFRP). The stress–strain behavior of the HSGC is compared with HSC for different levels and types of confinement. For low confining pressure, there was a definite peak followed by descending portion of the stress–strain curve, whereas for high confining pressure, initially, the stress increases nonlinearly with strain, and after reaching a certain level of stress, it becomes asymptotic to a positive slope straight line. A single equation is proposed for predicting all curves of HSGC and HSC for low as well as high confining pressures. The validation of the model is also successfully shown with the data taken from the literature for a wide range of confinement levels.