STRUCTURAL BEHAVIOR OF ECO-EFFICIENT GEOPOLYMER CONCRETE BEAM–COLUMN JOINTS UNDER LATERAL MONOTONIC LOADING

Ordinary Portland cement (OPC) is the essential binding material to produce the OPC concrete. Production of OPC is recently attaining a rate of 2.6 billion ton per year worldwide and growing 5% annually. OPC contributes at rate of 5 – 8% of human-worldwide CO2 emissions which are the greenhouse gases pollute the atmosphere. Geopolymer concrete (GPC) is a creative, sustainable, economical and eco-friendly material for construction industry, which is a suitable alternative to the OPC concrete, able to extensively curb the CO2 emissions. To prepare this kind of concrete, a combination of pozzolanic material such as fly ash (FA), and/or ground granulated blast furnace slag (GGBS) rich with silica and alumina can react with alkaline activator solution producing aluminosilicate gel, acting as a superb binding material for fine and coarse aggregates under special conditions of curing. This study highlights the recent explorations on geopolymer mortars and concrete. Effect of chemicals such as sulphuric acid, effect of fly ash partial replacement with different binding materials, effect of concentration of alkaline activator solutions and the effect of temperature and time of curing variation have been discussed on durability and mechanical properties of geopolymer concrete. Results have shown superb resistance of geopolymer concrete to the detrimental effects of sulphuric acid on weight and compressive strength. Furthermore, fly ash partial replacement with silica fume, OPC or GGBS, or nanosilica inclusion in GPC has a positive effect on the GPC properties. Finally, using high concentration of sodium hydroxide has a detrimental effect on GPC properties.

Expanding the world’s infrastructure drives up demand for building materials, particularly ordinary Portland cement (OPC) concrete, whose high carbon dioxide (CO2) emissions have a detrimental effect on the environment. To address this issue, researchers looked into employing alternative supplementary cementitious materials (SCMs), including metakaolin (MK), which is derived from calcined kaolin clay with pozzolanic properties, to partially or completely replace OPC in concrete. This review article examines the MK’s application in alkali-activated materials (AAMs) and OPC-based concrete. By interacting with calcium hydroxide, MK functions as a pozzolanic additive for OPC concrete, enhancing its mechanical qualities and durability. The use of MK as a source material in AAMs, a newly developed class of sustainable binders, is also covered in this article. The effects of different combinations of MK with additional SCMs, including fly ash (FA), ground granulated blast furnace slag (GGBFS), silica fume, and rice husk ash, on the characteristics of alkali-activated concrete both in its fresh and hardened states, are compiled. The majority of the articles considered in this study are from the past decade, while some relevant articles from 2014 and earlier are also taken into account. The results showed that adding MK to concrete in combination with FA or GGBFS has excellent synergistic effects on microstructural development, pozzolanic activity, and strength increases. In particular, the MK–FA mix demonstrated the most encouraging performance gains. Because of its large surface area, the use of nano-MK helped achieve a denser geopolymer structure and improve mechanical properties. The best curing temperatures for MK-based geopolymers to gain strength were found to be between 40 and 80°C for a total of 28 days. The review also pointed out that the compressive strength and geopolymerization process of MK-based geopolymers were enhanced by increasing the mass ratio of Na2SiO3 to NaOH and NaOH concentration. Nevertheless, geopolymerization was hampered by unnecessarily high alkali concentrations. Moreover, the compressive strength was increased by partially replacing MK with TiO2 or GGBFS. The synergistic effects of combining MK with other SCMs to improve concrete performance highlight the potential of MK-based solutions in lowering the environmental footprint of concrete buildings.

Geopolymer concrete (GPC) is the most advanced form of concrete amongst the various types of concrete developed so far. This paper aims at investigating the feasibility of using Ground Granulated Blast furnace Slag (GGBS) as a base material for geopolymer concrete. Effect of dolomite, which is a by-product from rock crushing plant on GGBS based GPC, was studied. Maximum compressive strength was obtained when GGBS and dolomite were proportioned at 70:30. Steel fibres were added to geopolymer concrete (SFGPC) to improve the ductile behaviour and its brittleness index was compared with Ordinary Portland Cement (OPC) concrete. Strength and behaviour of GGBS-Dolomite GPC and SFGPC flexural member subjected to cyclic loading are explained in this paper. Steel fibres are added at 0.25%, 0.5% and 0.75% volume fraction of concrete. Properties such as load deflection behaviour, ultimate load, crack width and ductility were compared with OPC concrete beams.

Influence of repeated heating–cooling cycles and exposure duration on mechanical, electrical, and durability properties of geopolymer concrete

Geopolymer concrete is an emerging and innovative alkali-activated concrete that has been growingly studied because of its superior mechanical strengths and durability properties. This study, therefore, investigates the utilization of both corncob ash (CCA) and ground granulated blast furnace slag (GGBFS) as source materials activating with both sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solutions in the production of geopolymer concrete (GPC). Sodium hydroxide was prepared in 12 molar concentration using Grade 30 MPa mix design ratio. GGBFS was replaced by CCA in varying percentages 20, 40, 60, 80, and 100% and cured in ambient conditions. Slump, density, and compressive strength of GPC were determined and compared with Portland Cement Concrete (PCC) of the same grade. The research findings indicate an optimal strength of 100% GGBFS with a compressive strength of 43.17MPa at 28 days curing for GPC compared with 35.12MPa for PCC. The result reveals that GPC has better strength than PCC and, CCA and GGBFS can be utilized as aluminosilicate materials to replace cement in the production of GPC.

Fly ash, GGBS, and silica fume based geopolymer concrete with recycled aggregates: Properties and environmental impacts

The major problem the world is facing today is the environmental pollution. In the construction industry mainly the production of Portland cement will causes the emission of pollutants results in environmental pollution. We can reduce the pollution effect on environment, by increasing the usage of industrial by-products in our construction industry. Geo- polymer concrete is such a one and in the present study, to produce the geo-polymer concrete the Portland cement is fully replaced with GGBS (Ground granulated blast furnace slag) and Metakaolin and alkaline liquids are used for the binding of materials. The alkaline liquids used in this study for the polymerization are the solutions of Sodium hydroxide (NaOH) and sodium silicate (Na2Sio3) of A53 which consists of SiO2 = 29.4%, Na2O = 14.7%, and water = 55.9% by mass is used. 10Molar Sodium hydroxide is taken for the preparation of different mixes by varying the percentages of GGBS (Ground granulated blast furnace slag) and Metakaolin. The cube specimens are taken of size 150mm x 150mm x 150mm for compression test. The curing was done directly by placing the specimens to direct sunlight. The geo- polymer concrete specimens are tested for their compressive strength at the age of 3, 7 and 28days and compared with conventional concrete. For this study M30 concrete mix was used for experimental work. The result shows that there is an increase in the strength of Geopolymer concrete up to 40%GGBS content and then it is decreasing. Therefore it is preferable to use 40%GGBS with Metakaolin to get high strength. Metakaolin and GGBS can be used as a replacement material for cement gives an excellent result in strength aspect and quality aspect since it is better than the control concrete. Key Words: Geopolymer concrete, GGBS, Metakaolin, Alkaline solutions, curing, compressive strength.

Among various eco-friendly building products, geopolymers are emerging as a potential replacement material for ordinary portland cement due to its energy efficiency and environmental protection. Though various eco-friendly cementitious materials in combination with geopolymer concrete (GPC) have been studied by various researchers, their effect on the behavior of GPC made with ground granulated blast furnace slag (GGBS) and metakaolin (MK) is, however, not well established. This paper investigates the mechanical properties of GPC and flexural behavior of geopolymer-reinforced concrete beams, comprising various percentages of fly ash (FA), GGBS, and MK. The FA was partially replaced with various proportions of GGBS and MK. All the concrete specimens are cast for 10 molarity (10M) and are tested as per Indian standard code. The compressive, split tensile, and flexural strength of the F50G25M25 (50% fly ash + 25% GGBS + 25% MK) mix are increased by 147.75%, 57.21%, and 36.08% respectively, over the control specimen (F90G5M5) (90% fly ash + 5% GGBS + 5% MK). The ultimate load-carrying capacity of a geopolymer reinforced concrete beam was enhanced by up to 30.43% for F50G25M25 mix. The experimental ultimate loads are compared with theoretical predicted loads, and good agreement with the theoretical model is found. Replacement of FA by GGBS and MK at 25% each significantly increased the mechanical properties and flexural behavior of GPC. Other cementitious materials beyond those used in this paper could be used to investigate the mechanical properties of GPC.

The characteristic global warming potential of ordinary Portland cement (OPC) makes it a huge challenge for researchers to weigh its enormous use with potentially feasible engineering properties versus the environmental impacts. The formulation of sustainable, economical, and greener supplementary cementitious materials (SCMs) is an ongoing phenomenon, attracting the large-scale attention of industry/ academia. The formulation of ferrock by David Stone with low embodied energy, lower consumption of natural resources and minimal global warming potential has paved the way for the use of novel material comprising iron powder, pozzolans (pulverised fly ash (PFA) and metakaolin (MK) and lime exhibiting at par performance with OPC. However, a gap has been identified in its formulation, raising a further research question on how it will perform if PFA and MK are replaced by ground granulated blast furnace slag (GGBS) or other pozzolans like silica fume (SF) etc., with different mix ratios. Therefore, an endeavour has been made in this study to identify the engineering properties with sustainable use of modified binary and ternary pozzolans/ GGBS in place of 20% PFA in conventional ferrock. The conventional ferrock contains 8% MK and 20% PFA (as binary pozzolans), 60% iron powder, 12% lime and 2% oxalic acid (set 1). An effort has been made to formulate the different mixes of 10,20,30,40 and 50% by keeping 60% iron powder, 12% lime, 8% MK and 2% oxalic acid constant but replacing 20% PFA with 20% GGBS (set 2), with 10%PFA+10%GGBS (set 3) and with 10%PFA+10%SF (set 4). A target compressive strength of C32/40 or M40 concrete was selected for this study to achieve and compare results with the control mix (0% ferrock) and conventional ferrock during the experimental investigation of modified novel materials. 10-20% ratios of modified mixes exhibited the best performance and achieved the threshold strength of 60 MPa of high-strength cement concrete. Maximum compressive strength of 65 MPa was achieved by the 10% mix of set 2 (20% GGBS), followed by 20% mix ratios of set 3 (10%PFA+10%GGBS) and set 4 (10%PFA+10%SF), achieving 64 MPa. Whereas the 10% mix of the conventional ferrock (set1) reached 63 MPa strength, and the control mix with no ferrock gained 57 MPa strength at 56 days of curing. Overall, an increase of 2-13% compressive strength was observed with10- 30% mixes of all the SCMs; however, a decrease of 3-27% was observed with 40-50% use of SCMs. The use of iron powder increased the ductility of ferrock-based SCMs mixes and exhibited more flexural strength. Set 3 performed the best in exhibiting up to 5.8 MPa flexural strength, followed by set 4, set 2 and lastly, set 1 of conventional ferrock. 20% and 30% mix ratios exhibited flexural strength of more than 5% MPa, better than 10% and 40/ 50% mixes. The study supports the use of 10-20% ferrock-based SCMs for high-strength concrete and 10-50% for concrete mixes with a target strength of C32/40 or M40 to decrease the CO2 footprints of the construction industry significantly.

Purpose Demand for Geopolymer concrete (GPC) has increased recently because of its many benefits, including being environmentally sustainable, extremely tolerant to high temperature and chemical attacks in more dangerous environments. Like standard concrete, GPC also has low tensile strength and deformation capacity. This paper aims to analyse the utilization of incinerated bio-medical waste ash (IBWA) combined with ground granulated blast furnace slag (GGBS) in reinforced GPC beams and columns. Medical waste was produced in the health-care industry, specifically in hospitals and diagnostic laboratories. GGBS is a form of industrial waste generated by steel factories. The best option to address global warming is to reduce the consumption of Portland cement production and promote other types of cement that were not a pollutant to the environment. Therefore, the replacement in ordinary Portland cement construction with GPC is a promising way of reducing carbon dioxide emissions. GPC was produced due to an alkali-activated polymeric reaction between alumina-silicate source materials and unreacted aggregates and other materials. Industrial pollutants such as fly ash and slag were used as raw materials. Design/methodology/approach Laboratory experiments were performed on three different proportions (reinforced cement concrete [RCC], 100% GGBS as an aluminosilicate source material in reinforced geopolymer concrete [GRGPC] and 30% replacement of IBWA as an aluminosilicate source material for GGBS in reinforced geopolymer concrete [IGRGPC]). The cubes and cylinders for these proportions were tested to find their compressive strength and split tensile strength. In addition, beams (deflection factor, ductility factor, flexural strength, degradation of stiffness and toughness index) and columns (load-carrying ability, stress-strain behaviour and load-deflection behaviours) of reinforced geopolymer concrete (RGPC) were studied. Findings As shown by the results, compared to Reinforced Cement Concrete (RCC) and 100% GGBS based Reinforced Geopolymer Concrete (GRGPC), 30% IBWA and 70% GGBS based Reinforced Geopolymer Concrete (IGRGPC) (30% IBWA–70% GGBS reinforced geo-polymer concrete) cubes, cylinders, beams and columns exhibit high compressive strength, tensile strength, flexural strength, load-carrying ability, ultimate strength, stiffness, ductility and deformation capacity. Originality/value All the results were based on the experiments done in this research. All the result values obtained in this research are higher than the theoretical values.

Disposal of industrial solid wastes in a hydrologic environment can cause environmental risks due to the mobility of toxic trace elements. It is increasingly important to find simple and inexpensive treatments to remove undesirable elements from industrial solid wastes. One of the most important problems in the secondary steel mill industry is the disposition of dusts produced from electric arc furnace. A large quantity (10--20 kg) of electric arc furnace dust (EAFD) is generated per ton of steel produced. The Toxicity Characteristic Leaching Procedure (TCLP) shows that the total Cr and Cr (VI) concentrations (9.7 and 6.1 mg/L respectively) from the EAFD studied exceeded the Toxicity Characteristic Regulatory Level. Some heavy metals of EAFD like chromium are toxics and have high solubility. Chromium (VI) is particularly problematic because it must initially be reduced before fixed in an insoluble phase. To counter this problem, the use of ordinary Portland cement (OPC) and ground granulated blast furnace slag (GGBFS) was investigated. Column leaching test was performed to evaluate the leaching of EAFD amended with GGBFS and OPC under dynamic conditions simulating heap leaching. The goal of this study is to fred a simple and economic way to decrease contaminants in the leachate. Test columns have been set up to evaluate the effect of alkaline additives (OPC and GGBFS) on the geochemistry of drainage water. The control column consists of EADF only. A set of columns presents the effect of the addition of 5% by mass of OPC or GGBFS mixed homogeneously with the EAFD. Another set of columns was set up with the same quantities of OPC and GGBFS but concentrated at the base of the EAFD simulating a liner. Columns were fed three times weakly during 1 month. The parameters monitored after each flush of water include leachate volume, pH, electrical conductance and water quality (Cr-Ni-Pb-Zn concentrations). The leaching of the control (EAFD only) presents high Cr concentration. The addition of GGBFS and OPC increases the pH conditions and decreases metal concentrations. The concentration of OPC and GGBFS at the base of the EADF as a liner was the more efficient disposition. The use of a mixture of EAFD with 5% of OPC or GGBFS applied at the base of EADF heap is a simple and economic way to remove contaminant. In spite of a significant decrease in Cr concentration, values remain slightly above regulatory level.

Disposal of industrial solid wastes in a hydrologic environment can cause environmental risks due to the mobility of toxic trace elements. It is increasingly important to find simple and inexpensive treatments to remove undesirable elements from industrial solid wastes. One of the most important problems in the secondary steel mill industry is the disposition of dusts produced from electric arc furnace. A large quantity (10--20 kg) of electric arc furnace dust (EAFD) is generated per ton of steel produced. The Toxicity Characteristic Leaching Procedure (TCLP) shows that the total Cr and Cr (VI) concentrations (9.7 and 6.1 mg/L respectively) from the EAFD studied exceeded the Toxicity Characteristic Regulatory Level. Some heavy metals of EAFD like chromium are toxics and have high solubility. Chromium (VI) is particularly problematic because it must initially be reduced before fixed in an insoluble phase. To counter this problem, the use of ordinary Portland cement (OPC) and ground granulated blast furnace slag (GGBFS) was investigated. Column leaching test was performed to evaluate the leaching of EAFD amended with GGBFS and OPC under dynamic conditions simulating heap leaching. The goal of this study is to fred a simple and economic way to decrease contaminants in the leachate. Test columns have been set up to evaluate the effect of alkaline additives (OPC and GGBFS) on the geochemistry of drainage water. The control column consists of EADF only. A set of columns presents the effect of the addition of 5% by mass of OPC or GGBFS mixed homogeneously with the EAFD. Another set of columns was set up with the same quantities of OPC and GGBFS but concentrated at the base of the EAFD simulating a liner. Columns were fed three times weakly during 1 month. The parameters monitored after each flush of water include leachate volume, pH, electrical conductance and water quality (Cr-Ni-Pb-Zn concentrations). The leaching of the control (EAFD only) presents high Cr concentration. The addition of GGBFS and OPC increases the pH conditions and decreases metal concentrations. The concentration of OPC and GGBFS at the base of the EADF as a liner was the more efficient disposition. The use of a mixture of EAFD with 5% of OPC or GGBFS applied at the base of EADF heap is a simple and economic way to remove contaminant. In spite of a significant decrease in Cr concentration, values remain slightly above regulatory level.

Geopolymer concrete (GPC) emerging as the most innovative construction material, which not only reduces the requirement of Ordinary Portland cement (OPC) but also enhances the properties of the concrete as well, and decreases the ejection of harmful gases into the atmosphere like Carbon dioxide (CO2), Nitrogen, and Sulphur, Which is a prime concern for the environment. The need for concrete is raising uncharacteristically and so does for the OPC, to minimize the demand for OPC cementitious materials like Fly ash, Ground Granulated Blast Furnace Slag (GGBS), Silica Fume, Alccofine, Metakaolin, namely mineral admixtures used as partial or full replacements to the OPC. This present paper reports the properties of GPC made with Flyash, GGBS, and Alccofine for Mix M40- grade concrete the outcomes were contrasted with Nominal concrete which is made using 100 percent cement, Fly ash content of 50% was kept constant throughout the investigation whereas GGBS and Alccofine content varied with an interval of 5%. The concrete was tested for workability, strength, and durability aspects, an increment in the slump, and in the strength was noted, and great resistance was observed under the acid attack test for a GPC mixes, a combination of 50% Fly ash, 35% GGBS, and 15% Alccofine GPC mix was shown optimum results.

The use of Portland cement in concrete construction is under critical review due to high amount of carbon dioxide gas released to the atmosphere during the production of cement.In recent years, attempts to increase the utilization of fly ash to partially replace the use of Portland cement in concrete are gathering momentum.Most of this by-product material is currently dumped in landfills, creating a threat to the environment.We can reduce the pollution effect on environment, by increasing the usage of industrial by-products in our construction industry.Geo-polymer concrete is a concrete in which Portland cement is fully replaced by fly ash and GGBS (Ground granulated blast furnace slag).Geo-polymer concrete is a 'new' material that does not need the presence of Portland cement as a binder.Instead, the source of materials such as fly ash, that are rich in Silicon (Si) and Aluminum (AI), are activated by alkaline liquids to produce the binder.Hence it is the concrete with no Portland cement.The present study covers the use of plastic Waste in geo-polymer concrete as partial replacement of fine aggregate.Sand is replaced with plastic waste at 5, 10, and 15 percentages respectively.Alkaline liquids used in this study are the solutions of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3).Molarity of sodium hydroxide (10M) is considered.Fly ash and GGBS were used in different combinations and percentages respectively.This study is conducted to know the compressive strength of Geo-polymer concrete with plastic waste and to compare the same with Geo-polymer concrete without any replacement of fine aggregate.

Geopolymer concrete presents a sustainable alternative to ordinary Portland cement (OPC) by reducing cement usage and carbon emissions. This study develops a machine learning model to predict the compressive strength of geopolymer concrete made of recycled industrial by-products, such as ground granulated blast furnace slag (GGBS) and fly ash (FA) as binder materials, for enhanced mechanical performance and sustainability. A dataset of 169 mix designs from the literature was analysed to investigate the influence of 11 variables on compressive strength. Exploratory Data Analysis (EDA) confirmed the dataset’s consistency and identified GGBS content and Si/Ca ratio as key predictors. Multiple machine learning models—Linear Regression, Random Forest, XGBoost, Artificial Neural Network (ANN), and a ResNet-based deep learning model—were developed to predict compressive strength. After hyperparameter tuning, Random Forest and ANN achieved the highest predictive accuracy, with R2 values of 0.94 and 0.92, respectively. Feature importance analysis further reinforced the role of GGBS and chemical ratios in strength development. The results demonstrate the effectiveness of data-driven modelling in optimising geopolymer concrete design, reducing the need for extensive experimental work, and contributing to greener construction practices. This study contributes to the application of industrial by-products as viable, eco-efficient materials in infrastructure applications.