Geopolymer Concrete: A Material for Sustainable Development in Indian Construction Industries

Enhancing performance and sustainability of GGBFS-based self-compacting geopolymer concrete blended with coal bottom ash and metakaolin by using RSM modelling

This research study is performed on the self-compacting geopolymer concrete (SCGC) combining coal bottom ash (CBA) and metakaolin (MK) as a substitution for GGBFS alone and combined for analysing the fresh properties (slump flow, V-Funnel, and T50 flow), mechanical characteristics (compressive, splitting tensile and flexural strengths) and durability tests (permeability and sulfate attack test). Though, total 195 SCGC samples were made and tested for 28 days. It has been revealed that the consumption of CBA and MK as a substitution for GGBFS alone and combine in the production of SCGC is decreased the workability of SCGC while mechanical characteristics of SCGC are enhanced by utilizing CBA and MK as a substitution for GGBFS alone and combine up to 10%. In addition, the compressive, splitting tensile and flexural strengths were calculated by 59.40 MPa, 5.68 MPa, and 6.12 MPa while using the 5CBA5MK as a substitution for GGBFS in the production of SCGC after 28 days correspondingly. Furthermore, the permeability is decreased by growing the quantity of CBA and MK by the weight of GGBFS alone and jointly in the production of SCGC after 28 days. Besides, the minimum change in length of the SCGC specimen is recorded by 0.062 mm at 7.5MK7.5CBA while the maximum change in length is calculated by 0.11 mm at 10CBA10MK as a substitution for GGBFS at 180 days correspondingly. In addition, the embodied carbon is recorded reduce as the addition of CBA while it is getting higher when the accumulation of MK alone or combined with CBA in SCGC. Besides, response models for prediction were constructed and confirmed using ANOVA at an accuracy rate of 95%. The models' R2 fluctuated from 88 to 99%. It has been observed that the utilization of CBA and MK alone and together up to 10% as substitution for GGBFS in geopolymer concrete provides the best results therefore it is suggested for structural applications.

Fatigue analysis of ambient-cured geopolymer concrete for high-traffic pavements

The building sector is growing at a rapid rate, leading to an increased demand for construction materials. Concrete made with Ordinary Portland Cement (OPC) has long been the preferred choice due to its excellent bonding properties and versatility as demanded by construction process. However, the manufacturing of Ordinary Portland Cement (OPC) leads to negative impacts on the environment, with the cement sector responsible for around 5-8% of global CO2 emissions. In addition, the manufacture of OPC necessitates significant amounts of natural raw materials and energy. Contrastingly, using geopolymers promises to save substantial amounts of energy and reduce CO2 emissions. This potential has sparked growing interest in the application of geopolymers within transportation infrastructure. For pavements, the workability requirement is less, and hence, geopolymer concrete (GPC) is a viable option, but fatigue-resistance of GPC is not seen reported in literatures. This article evaluates the properties of geopolymer concrete with low-calcium fly ash partially replaced with ground granular blast furnace slag (GGBS) with 8 M NaOH alkaline solution and cured under ambient atmospheric conditions to evaluate its usage in pavements and develop an environmentally sustainable and durable GPC capable of withstanding heavy traffic. The study involves adjusting the pavement quality concrete (PQC) mix design; evaluating the mechanical characteristics, abrasion resistance, and shrinkage strain of the GPC; and analyzing its microstructure. Additionally, the study compares the fatigue life of GPC to that of PQC using various Weibull distribution approaches. The results showed that GPC4 (70% Fly ash and 30% GGBS) mix achieved best results at 28 days, with a compressive strength of 45.68 MPa, split tensile strength of 3.76 MPa, and flexural strength of 4.62 MPa. Also, shrinkage strains were nearly 31% lesser than PQC at 90 days. In addition, developing GPC needs 27% lesser embodied energy than PQC. Fatigue analysis prove that ambient cured fly ash-GGBS based geopolymer concrete with 8 M NaOH exhibits less stress development than PQC at medium loads, even though it is brittle. Thus, the study proves that it is suitable as a material for pavements to resist medium-loaded traffic-resisting pavements.

Review of the Influence of Acrylate Lotion on the Properties of Cement-Based Materials

Polymer-modified cement-based materials have been widely used in the construction field. Acrylate lotion significantly improves durability, toughness, and bending resistance, especially durability, because the porosity of cement-based materials is reduced, preventing the entry of harmful ions and water. When acrylate lotion was at 20%, the resistance of cement-based materials to chloride ion penetration increased by 40%. At the same time, the fracture toughness of cement-based materials modified with acrylate lotion and carbon nanotubes increased by 10-15%. The flexural strength of cement-based materials modified by acrylate lotion and fiber increased by 29%. Additives such as TiO2 have a unique impact on the modification of cement-based materials, which has attracted the interest of researchers. This paper reviewed the performance of acrylate lotion-modified cement-based materials and the application of acrylate lotion in the field, which systematically increased the durability, mechanical properties, and waterproof properties of cement-based materials when acrylate lotion was modified, acrylate lotion was modified with nanomaterials, acrylate lotion was modified with other polymers, acrylate lotion was modified with fiber, and when acrylate lotion was modified with other additives. The shortcomings of acrylate lotion modification with different materials were reviewed and evaluated, and the comprehensive performance of cement-based materials modified by acrylate lotion was expected to achieve maximum strength improvement under the synergistic effect of various modifications.

Possibilities of Checking Water Content in Porous Geopolymer Materials Using Impedance Spectroscopy Methods

The porous geopolymer has been tested for its content of water using impedance methods. The pores of the material were filled with distilled water using a desiccator and a vacuum pump. An analysis of differential scanning calorimetry (DSC) was carried out in the next step to check the content of water, porosity and approximate value of specific heat of the geopolymer. Additionally, mercury porosimeter has been used for checking the porosity. The geopolymer material characterized in this way was subjected to impedance tests aimed at developing a quick method for assessing the water content in the material. Impedance measurements have been realized on an electrochemical workstation applying a 50 mV non-destructive amplitude of the potential and a frequency range of 1 Hz to 100 kHz. Change in the module of impedance and the phase shift angle were measured while the material was dried out. Significant differences were observed. The obtained graphs were simulated using a schematic model consisting of constant phase elements (CPEs) and a resistor (R). These values showed mechanisms of charge conduction. A simple method for assessing the water content of a porous geopolymer has been proposed in this paper. The real and imaginary impedance values were shown in Nyquist graphs. These graphs have characteristic maxima that move according to a linear equation with decreasing water content. Changes in Nyqiust charts are clearly visible even with small changes in the water content of the material and can be very useful for assessing it.

Review of Geopolymer Nanocomposites: Novel Materials for Sustainable Development

The demand for geopolymer materials is constantly growing. This, in turn, translates into an increasing number of studies aimed at developing new approaches to the methodology of geopolymer synthesis. The range of potential applications of geopolymers can be increased by improving the properties of the components. Future directions of studies on geopolymer materials aim at developing geopolymers showing excellent mechanical properties but also demonstrating significant improvement in thermal, magnetic, or sorption characteristics. Additionally, the current efforts focus not only on the materials' properties but also on obtaining them as a result of environment-friendly approaches performed in line with circular economy assumptions. Scientists look for smart and economical solutions such that a small amount of the modifier will translate into a significant improvement in functional properties. Thus, special attention is paid to the application of nanomaterials. This article presents selected nanoparticles incorporated into geopolymer matrices, including carbon nanotubes, graphene, nanosilica, and titanium dioxide. The review was prepared employing scientific databases, with particular attention given to studies on geopolymer nanocomposites. The purpose of this review article is to discuss geopolymer nanocomposites in the context of a sustainable development approach. Importantly, the main focus is on the influence of these nanomaterials on the physicochemical properties of geopolymer nanocomposites. Such a combination of geopolymer technology and nanotechnology seems to be promising in terms of preparation of nanocomposites with a variety of potential uses.

A Study on the Fire-Retardant and Sound-Proofing Properties of Stainless Steel EAF Oxidizing Slag Applied to the Cement Panel

Because of incomplete recycling resource management and technology development, inorganic sludge and slag has been misused in Taiwan. The recycling of inorganic sludge and slag is a pressing crisis. Resource materials with a sustainable use value are misplaced and have a significant impact on society and the environment, which greatly reduces industrial competitiveness. To solve the dilemma of EAF oxidizing slag recycled from the steel-making process, it is important to find solutions to improve the stability of EAF oxidizing slags based on the innovative thinking of the circular economy. We can improve the value of recycling resources and solve the contradiction between economic development and environmental impact. The project team intends to investigate the development and application of reclaiming EAF oxidizing slags blended with fire-retardant materials, which will integrate R&D work from four different aspects. First, a verification mechanism is carried out to establish stainless steel furnace materials. Suppliers must be assisted in conducting quality management for EAF oxidizing slags to ensure the quality of the materials provided. Next, high-value building materials must be developed using slag stabilization technology, and fire-retardant tests must be conducted on the recycled building materials. A comprehensive evaluation and verification of the recycled building materials must be undertaken, and high-value green building materials must be produced with fire-retardant and sound-proofing characteristics. Integration with national standards and regulations can drive the market integration of high-value building materials and the industrial chain. On the other hand, the applicability of existing regulations to facilitate the legal use of EAF oxidizing slags will be explored.

Influence of Waste Glass Particle Size on the Physico-Mechanical Properties and Porosity of Foamed Geopolymer Composites Based on Coal Fly Ash

In order to protect the environment and counteract climate change, it is necessary to take any actions that enable a reduction in CO₂ emissions. One of the key areas is research focused on developing alternative sustainable materials for construction to reduce the global demand for cement. This work presents the properties of foamed geopolymers with the addition of waste glass as well as determined the optimal size and amount of waste glass for improving the mechanical and physical features of the produced composites. Several geopolymer mixtures were fabricated by replacing coal fly ash with 0%, 10%, 20%, and 30% of waste glass by weight. Moreover, the effect of using different particle size ranges of the addition (0.1-1200 µm; 200-1200 µm; 100-250 µm; 63-120 µm; 40-63 µm; 0.1-40 µm) in the geopolymer matrix was examined. Based on the results, it was found that the application of 20-30% of waste glass with a particle size range of 0.1-1200 µm and a mean diameter of 550 µm resulted in approximately 80% higher compressive strength in comparison to unmodified material. Moreover, the samples produced using the smallest fraction (0.1-40 µm) of waste glass in the amount of 30% reached the highest specific surface area (43.711 m²/g), maximum porosity (69%), and density of 0.6 g/cm³.

Experimental Analysis and Establishment of Strength Attenuation Model of POM Fiber Reinforced Geopolymeric Recycled Concrete under Freeze-Thaw Cycles

Geopolymeric recycled concrete (GRC) is a new low-carbon building material that uses both construction and industrial solid waste to replace natural aggregate and cement. GRC is similar to geopolymeric concrete (GPC) in that it has good mechanical properties but needs to be improved in terms of frost resistance. Previous studies have shown that polyoxymethylene fiber (POM fiber) can improve the shrinkage and durability of concrete and is superior to other commonly used fibers. Therefore, this paper explores adding POM fiber to GRC to improve its frost resistance. In this paper, the influence of different volumes and lengths of POM fiber on the frost resistance of geopolymeric recycled concrete (PRGRC) is studied. By measuring the changes in mass loss rate, relative dynamic elastic modulus, and compressive strength of PRGRC under different cycles, the improvement effect of POM fiber on the freeze-thaw damage of GRC is analyzed, and the strength attenuation model of PRGRC is established. The results show that the increase in POM fiber content can effectively slow down the mass loss of PRGRC in the freeze-thaw cycles, the reduction rate of relative dynamic elastic modulus, and the reduction rate of compressive strength. This shows that POM fiber can effectively improve the frost resistance of PRGRC, and the effect of 6 mm POM fiber on the freeze-thaw damage of PRGRC is better than 12 mm POM fiber. According to the test results, the existing strength attenuation model is further modified, the attenuation model of PRGRC compressive strength under the freeze-thaw cycle is obtained, and the model fitting effect is good. The strengthening mechanism of POM fiber is explained by the structural relationship between POM fiber and concrete matrix in the SEM micrograph of PRGRC. The research results provide a scientific basis for the applicability of POM fiber in geopolymeric cementitious materials and improving the frost resistance of PRGRC.

A Review on the Incorporation of Diatomaceous Earth as a Geopolymer-Based Concrete Building Resource

The development of geopolymer building composites at a lower cost with a smaller carbon footprint may lessen the growing concerns about global warming brought on by emissions of a critical greenhouse gas (CO₂) paired with the high production costs in the cement sector. Diatomaceous earth, commonly used as an admixture or partial replacement of cement owing to its most effective pozzolanic properties, has been investigated as a precursor in geopolymer concrete development. Several studies have been examined to develop a greater understanding of its characterization, inclusion status, and impacts on the performance aspects of concrete. The literature review showed that using diatomaceous earth is one of the effective ways to create sustainable, insulating, lightweight building materials while minimizing the harmful economic and environmental effects of industrial solid wastes. However, since most studies have focused on its integration as a partial cement substitute or a replacement for fine aggregate, further research on diatomaceous earth-based clinker-free concrete is required. A lack of research on geopolymer concrete's reinforcement with either natural or synthetic fibers, or a combination of the two, was also discovered. This review also showed that there has been remarkably little effort made towards theoretical property correlation modeling for predicting concrete performance. It is anticipated that the detailed overview presented herein will guide potential researchers in defining their future paths in the study area.

Flexural Performance and Microstructural Studies of Trough-Shaped Geopolymer Ferrocement Panels

Geopolymer mortar is the best solution as an alternative to cement mortar in civil engineering. This paper deals with the effect of geopolymer mortar on the strength and microstructural properties under ambient curing conditions. In this research, geopolymer mortars were prepared with fly ash and steel slag (in the ratio 1:2.0, 1:2.5 and 1:3.0) as precursors with NaOH and Na₂SiO₃ as activator solution solutions (in the ratios of 0.5, 0.75 and 1.0) with concentrations of NaOH as 8 M, 10 M, 12 M and 14 M to study the compressive strength behaviour. From the experimental results, it was observed that the geopolymer mortar mix with the ratio of fly ash and steel slag 1:2.5, 12 M NaOH solution and the ratio of NaOH and Na₂SiO₃ 0.5 exhibits the maximum compressive strength results in the range of 55 MPa to 60 MPa. From the optimized results, ferrocement panels of size 1000 mm × 1000 mm × 50 mm were developed to study the flexural behaviour. The experimental results of the flexural strength were compared with the analytical results developed through ABAQUS software. It was observed that the Trough-shaped geopolymer ferrocement panel exhibits 56% higher value in its ultimate strength than the analytical work. In addition to the strength properties, microstructural analysis was carried out in the form of SEM, EDAX and XRD from the tested samples.

A Comprehensive Review on Fly Ash-Based Geopolymer

The discovery of an innovative category of inorganic geopolymer composites has generated extensive scientific attention and the kaleidoscopic development of their applications. The escalating concerns over global warming owing to emissions of carbon dioxide (CO2), a primary greenhouse gas, from the ordinary Portland cement industry, may hopefully be mitigated by the development of geopolymer construction composites with a lower carbon footprint. The current manuscript comprehensively reviews the rheological, strength and durability properties of geopolymer composites, along with shedding light on their recent key advancements viz., micro-structures, state-of-the-art applications such as the immobilization of toxic or radioactive wastes, digital geopolymer concrete, 3D-printed fly ash-based geopolymers, hot-pressed and foam geopolymers, etc. They have a crystal-clear role to play in offering a sustainable prospect to the construction industry, as part of the accessible toolkit of building materials—binders, cements, mortars, concretes, etc. Consequently, the present scientometric review manuscript is grist for the mill and aims to contribute as a single key note document assessing exhaustive research findings for establishing the viability of fly ash-based geopolymer composites as the most promising, durable, sustainable, affordable, user and eco-benevolent building materials for the future.