Geopolymer Research Articles

Explicable AI-based modeling for the compressive strength of metakaolin-derived geopolymers

Geopolymers (GPs) are produced using a variety of alumina and silica-rich ingredients, including natural sources, such as calcined clays, as well as waste by-products, like fly ash and slag. It is difficult to measure the effect of each parameter on the strength of GP composites via experimental research. In this regard, this research aimed to build artificial intelligence (AI)-aided estimation models to quantify the impact of mix proportions on the compressive strength (CS) of MK-based GP mortar. Gene expression programming (GEP) and multi-expression programming (MEP) tools were used for models' development due to their advantage of yielding model equations for future predictions. Hyperparameters in GEP and MEP were systematically adjusted to enhance the models' optimal predictability. The regression and error analysis proved the superiority of MEP models over GEP models. In comparison to the GEP model, which had R2, MAE, MSE, RMSE, and objective function values of 0.90, 4.02, 25.3, 5.03, and 0.08, respectively, the MEP model demonstrated greater accuracy with values of 0.96, 3.24, 16.4, 4.05, and 0.02 respectively. Furthermore, SHapley Additive exPlanations (SHAP) analysis was conducted to determine the effect of various parameters on the CS of MK-based GP mortar. The established models' equations may be exploited to assess the CS of MK-based GP composites with various input parameters, hence reducing the need for further laboratory testing. Implementing this approach not only improves the efficiency of material design but also encourages the sustainable utilization of locally accessible resources in the manufacturing of geopolymers.

Promoting the use of geopolymer and alkali-activated materials through the identification of critical factors and strategies

Geopolymers (GP) and alkali-activated materials (AAMs) technology are emerging as eco-friendly and sustainable alternatives to traditional binders like Ordinary Portland cement (OPC), offering significant environmental benefits. Despite more than four decades of research and development, the commercial exploitation of GP and AAMs remains unrealised. In an attempt from this research paper to identify key success factors and limitations of this technology and propose strategies to exploit the available opportunities and address significant challenges hindering the widespread adoption of GP and AAMs in the global green construction market. The following comprehensive approach was undertaken to achieve the aforementioned objectives, this involved a thorough critical literature review and the formulation of a triple SWOT (Strengths, Weaknesses, Opportunities, and Threats) - Analytical Hierarchy Process (AHP) - TOWS hybrid analysis. The results demonstrate that GP and AAMs are promising materials highlighting strengths derived from their remarkable performance and durability properties, as well as the potential opportunities for GP and AAMs to reduce the environmental impact by using by-products, particularly local ones “zero-kilometre”, aligns with the objectives of sustainability and the circular economy, compared to conventional materials. However, the findings confirm experts’ positive assessments of GP and AAMs technology, several barriers that could critically threaten their development and implementation. These barriers include the absence of standards, design complexity, feasibility and performance of the final product dependent on variation factors, and handling difficulties. Finally, a set of strategies has been established to implement GP and AAMs by encouraging adoption through the implementation of a regulatory framework supported by the government. These strategies include developing local codes and test methods, providing economic incentives, fostering cooperative research globally, and organizing awareness campaigns. This article will help to provide a solid foundation for future research aimed at resolving controversial issues related to the implementation of GP and AAMs technology and promoting a positive perception of GP and AAMs among all stakeholders and decision-makers.

Development of geopolymer and cement-based shotcrete mortar: Impact of mix design parameters and spraying process

Shotcrete mortar is used in various construction works, including repair, tunneling, mining, and slope stabilization, among others. Traditionally, cement is used to produce shotcrete mortars with high viscosity, flowability, and early strength. Geopolymers (GP) have the potential to replace cement in shotcrete mortars, owing to their ability to reduce the material’s environmental footprint without compromising performance. This investigation assesses the feasibility of utilizing fly ash and blast furnace slag-based GP mortars produced with dune sand in shotcrete applications while comparing them to cement-based mixtures. The GP and cement-based shotcrete mortars were designed to have similar yield stress values. The evaluated properties included the initial flow, thickness layer, rebound material, rheological properties, setting time, compressive strength, ultrasonic pulse velocity, and pull-off bonding strength. Test results showed direct relationships between the yield stress and initial flow values, as well as between the buildup thickness and plastic viscosity, revealing that GP mortars were suitable for shotcrete applications, specifically those produced with flow values of 18.5 cm or less. GP mixtures produced with higher slag content than fly ash, higher sand content compared to binder, higher SH molarity, and lower solution content achieved higher buildup thickness owing to their higher viscosity. In the second phase, the performance of four mixes with different initial flows was assessed at various pumping flow rates and distances between the wall and machine pipe nozzle. The findings confirmed that these spraying parameters are crucial to improve the shotcrete performance of GP mortar with varying fresh behaviors.

Solar/microwave-driven composite membrane evaporation and its application in seawater desalination

Increased economic growth and population expansion has heightened the demand for water resources, leading to escalating levels of water scarcity. Sustainable seawater desalination methods, powered by renewable energy, offer promising solutions to the long-standing global water shortage. This study presents a method for seawater desalination that employs eco-friendly materials. The approach involves utilizing metakaolin-based porous geopolymer (GP) as the base material, and depositing graphene oxide (GO) to create a graphene oxide geopolymer (GOGP) composite membrane. The membrane undergoes in-situ self-reduction to obtain reduced graphene oxide geopolymer (rGOGP). The study examines the composition, microstructure, and water evaporation performance of the composite membrane under both solar/microwave-driven. The results show that, under microwave conditions with a frequency of 2450 MHz and power of 400 W, the evaporation rate can reach up to 4.13 kg·m−2·h−1, doubling the evaporation rate achieved through solar-driven evaporation at an equivalent efficiency level. Furthermore, the evaporation rate of the composite membrane remains consistent when exposed to high-concentration saltwater of 15 wt%. Notably, the removal rates of Na+, K+, Ca2+, and Mg2+ all exceed 99 %, meeting the drinking water requirements established by the World Health Organization. This study provides a novel approach to seawater desalination utilizing environmentally friendly materials and clean energy sources.

Fire resistance of phosphoric acid activated metakaolin geopolymer

Fire resistance is a key advantage of geopolymer (GP) materials. While most research focuses on alkali-activated GPs, this study examines the fire resistance of phosphoric acid-activated GPs with varying phosphorus-to-aluminum (P/Al) molar ratios. By activating metakaolin with different ortho-phosphoric acid (H3PO4) solutions, it was found that GPs with P/Al > 0.59 exhibited intumescence during fire tests, resulting in a 110 °C lower backside temperature (310 °C) compared to non-intumescent GPs (420 °C). Physico-chemical changes were analyzed before and after fire tests using DMA, TGA NMR, EPMA, and XRD. The study revealed dehydration, crystallization, and rheological changes, with NMR showing transitions from Al(VI) to Al(IV), full condensation of phosphorus species, and Si-O-Al to Si-O-Si bonds. Intumescence was linked to GP softening between 100 and 160 °C, achievable only with a P/Al ratio ≥ 0.74, with no additional benefits from excess phosphorus.

Mechanistic insights into molybdenum immobilization within geopolymer waste form

Molybdenum (Mo) tends to form highly mobile, non-sorbing complex redox species, which complicates its immobilization and encapsulation in cement and glass matrices. This study explores the potential of incorporating Mo into an alternative green cementitious material known as geopolymer (GP). By employing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), morphological analysis, and nitrogen adsorption-desorption techniques, we obtained comprehensive insights into the chemical behavior of Mo and its impact on the morphology and structure of the GP matrix. XRD and TGA analysis demonstrated that increasing Mo content significantly enhances the crystallinity and thermal stability of the GP matrix, attributed to Mo field effects. High-resolution SEM, TEM, and EDS mapping revealed the structural encapsulation of Mo-rich cavities within the GP waste form. A decrease in leaching rates with higher Mo content, alongside reduced pore volume and pore size, underscores the material's chemical durability. Post-leaching characterizations confirmed that the GP retains excellent structural strength with minimal changes in mesoporosity and surface area. This resilience highlights the effectiveness of GPs in immobilizing non-sorbing species like MoO32−, making them ideal for long-term waste management.

Carbon nanotube fibers as efficient p- and n-type thermoelements within geopolymers: A route for large-scale thermal energy harvesting from building structures

This study reports for the first time, the thermoelectric (TE) performance of continuous p- and n-type carbon nanotube fiber (CNTF) filaments integrated within a sustainable, fine-grained geopolymer (GP) based concrete matrix for the complete replacement of cement with supplementary cementitious materials towards CO2 emissions reduction policy. Moreover, CNTF as CO2 negative, conductive, durable and lightweight material could multidimensionally contribute on the achievement of sustainability goals. Herein, pristine CNTF filaments were molecularly modified with p- and n-type aqueous-based dopants in order to stably tune their intrinsic semi-conducting properties via a facile and scalable dip-coating process. The achieved Seebeck coefficient values of the optimized p- and n-type CNTF were +45.2 μV/K and −38.4 μV/K, respectively. Thereafter, the p- and n-type CNTF filaments were employed as pillar-like thermoelectric elements incorporated within a GP mixture for the assembly of a structural thermoelectric generator (TEG) device. The obtained TEG-enabled GP-based concrete demonstrator comprising of 8 p-n serially interconnected junctions is capable of generating a power output of 0.3 μW at an applied through-thickness temperature gradient (ΔT) of 50 Κ. Subsequently, the experimental work was validated using coupled field of TE simulations. Self-powered infrastructures are forecasted to efficiently benefit from available ΔT on large-scale upon their operational lifetime, further promoting future net-zero energy consumption concepts.

Molecular Insights into Adhesion at Interface of Geopolymer Binder and Cement Mortar.

The degradation of concrete and reinforced concrete structures is a significant technical and economic challenge, requiring continuous repair and rehabilitation throughout their service life. Geopolymers (GPs), known for their high mechanical strength, low shrinkage, and durability, are being increasingly considered as alternatives to traditional repair materials. However, there is currently a lack of understanding regarding the interface bond properties between new geopolymer layers and old concrete substrates. In this paper, using advanced computational techniques, including quantum mechanical calculations and stochastic modeling, we explored the adsorption behavior and interaction mechanism of aluminosilicate oligomers with different Si/Al ratios forming the geopolymer gel structure and calcium silicate hydrate as the substrate at the interface bond region. We analyzed the electron density distributions of the highest occupied and lowest unoccupied molecular orbitals, examined the reactivity indices based on electron density functional theory, performed Mulliken charge population analysis, and evaluated global reactivity descriptors for the considered oligomers. The results elucidate the mechanisms of local and global reactivity of the oligomers, the equilibrium low-energy configurations of the oligomer structures adsorbed on the surface of C-(A)-S-H(I) (100), and their adsorption energies. These findings contribute to a better understanding of the adhesion properties of geopolymers and their potential as effective repair materials.

Mechanical and durability properties of polymer fiber reinforced one-part foam geopolymer concrete: A sustainable strategy for the recycling of waste steel slag aggregate and fly ash

This paper assesses the feasibility of geopolymers (GPs) for use as lightweight foamed concrete, a crucial step towards reducing the carbon footprint and conserving natural resources. A powder activator (i.e., sodium metasilicate) less harmful to the environment was used to activate the fly ash-based GPs, while the limestone aggregates were gradually replaced by up to 100 % waste slag materials to conserve natural resources. Polypropylene fibers were incorporated at high dosage rates of 1 % or 2 %, by volume, to reduce the concrete density and improve its durability properties. Tested properties include flow, density, water absorption, porosity, thermal conductivity, mechanical strengths, drying shrinkage, and resistance to sulfate attack, freeze/thaw cycles, and elevated temperature. Results showed that the concrete mechanical properties improved when the limestone aggregate was replaced by slag materials, but the density and thermal conductivity were slightly curtailed at higher addition rates. The use of polypropylene fibers proved efficient to improve the resistance to freeze/thaw cycles, drying shrinkage, and expansion due to sulphate attack. Such data can help sustain the green building industry development by reducing the carbon footprint and conserving natural resources in foamed concrete applications.

Effect of the Al/Si ratio on intumescent Na-based geopolymer

This research investigates the fire resistance properties of alkali activated Na-based geopolymers (GP), used as steel protective coatings. The effect of different Al/Si molar ratios (0–0.54) is evaluated fire test. When coated on a steel plate, GP having the smaller Al/Si ratio exhibits an intumescent behavior with the highest expansion. When Al/Si = 0, the temperature at the backside of the steel plate is 313 °C which is decreased by 347 °C compared to an uncoated steel plate (660 °C). After fire testing, the GP physico-chemical properties are characterized with optical microscopy, Electron probe micro-analysis, dynamic mechanical analysis. According to stiffness test results, when the temperature approaches 100 °C, the GP with a given Al/Si ratio (different from zero) softens and expands (intumescence). The greater the Al/Si ratio in the GP, the more rigid the structure; this phenomenon limits expansion, and hence, lowers the fire protection.

Effect of Zr-glass fibers waste on the mechanical, structural, and durability of eco-friendly geopolymers based on natural pozzolan: A Box-Behnken design approach

Geopolymer (GP) materials are attracting increasing interest as a promising alternative to conventional cement-based materials, due to their beneficial characteristics. This article presents the preparation of two series of GP composites based on natural pozzolan (Pz), reinforced with varying percentages (0, 0.5, 1, 1.5, and 2 %) of short fiberglass waste rich in zirconia (Zr-GFW). Two alkaline activation solutions were used with a 1:1 ratio: NaOH (10 M): Na2SiO3 for the first series, and NaOH (12 M): Na2SiO3 for the second series. The effect of Zr-GFW incorporation on the structural, physical, mechanical, and chemical properties was investigated. Besides, a comparison between the two series with the different concentrations of alkaline solutions was also discussed. XRD analysis shows that no significant reaction occurred between zirconia and Pz-based GP matrix. The results show that a 1 % Zr-GFW is sufficient for excellent mechanical strength, up to 65 MPa, and good physical properties. Furthermore, based on the Box-Behnken design statistical method, the developed response surface methodology model shows a strong fit to the experimental data, with high values of R² (0.9998). In this model, the compressive strength studied is 64.28 MPa. After exposure to an 80 % solution of acetic acid for 60 days, the evaluation of chemical durability showed that the dense structure of the studied GP composites resisted the acid attack tests, as confirmed by SEM analysis. The percentage weight loss (%WL) of the GP composites ranges from 14.66 % to 16.15 %, resulting in a decrease in compressive strength of up to 55 %. However, this reduction is better than several previous works. The findings suggest that these GP composites not only contribute to waste management but also enhance the energy performance of buildings.

Microstructural and thermal characterization of polyethylene fiber-reinforced geopolymer composites

The use of geopolymer (GPL) as a non-combustible mineral matrix for fiber-reinforced composites and environmentally acceptable building materials is growing. When fibers are added to GPL, its brittle behavior changes to ductile or quasi-ductile, producing fiber-reinforced GPL composites that function well. The novelty in the present research involves analyzing the effects of high temperature and polyethylene (PE) fiber content on mechanical and microstructural properties to determine how PE fiber reinforcement influences the thermal performance of GPL composites. In this study, the main objective is to assess various GPL mixes to investigate how the inclusion of PE fiber and exposure temperature affect the material's performance after being subjected to elevated temperatures. These included compression tests, flexural tests, scanning electron microscopy, bubble parameter testing, thermogravimetric and differential thermal analysis, and mass loss measurement. The PE fiber concentrations varied between 0 % and 1.5 % by volume of the mix, and the exposure temperatures were established at 25, 200, 400, 600, and 800 °C. A two-way ANOVA analysis was performed to examine the significance of variation in the results due to the addition of PE fibers and elevated temperatures. According to the results, the GPL mortar observed a significant mass loss as the temperature rose from 25 °C to 250 °C. But from 250 °C to 710 °C, there was very little mass loss, and from 710 °C to 800 °C, there was no more loss. The GPL mortar thickened as the temperature increased, but more pores and cracks appeared. At 25 °C, adding PE fibers to GPL improved compressive strength by 16.2 %–35.55 % for 0.25 %–1.50 % dosages. Over 1.0 % led to a significant reduction because of uneven distribution, compromising homogeneity, and increasing porosity. The melted fiber defects had a minor effect on the strength of the mortar, even if the PE fiber broke down at higher temperatures. With an ideal fiber content of 1.50 % below 200 °C, PE fibers greatly enhanced the flexural properties of GPL mortar, resulting in a 6.30 %–58.00 % increase in flexural strength. Conclusively, incorporating PE fibers improves the flexural strength of GPL up to 200 °C, but beyond this temperature, there is a significant decline of the flexural strength, showing the fibers' effectiveness up to a specific temperature.

Silica-based geopolymers admixture of borosilicate waste glasses: A green material for gamma radiation shielding applications

The gamma shielding parameters of an admixture of waste borosilicate glass (BS) and geopolymer (GP) made from activated metakaolin are presented in the present study. The influence of the BS quantity on the density and different gamma shielding quantities is investigated over a wide gamma energy range. Four batches of the G-BS composite were prepared using the solid-state diffusion method, containing 0 (G), 10 % (G-10BS), 20 % (G-20BS), and 30 % (G-30BS) by weight of BS, respectively. The chemical compositions of the G-xBS samples were determined through X-ray fluorescence spectrometry. In addition, the density of the BS-doped geopolymers was determined using the liquid displacement method using deionized water as the displacement fluid. The theoretical determination of estimating shielding parameters began by estimating the mass (μρ) and linear (μ) attenuation coefficients of the geopolymers for photon energies in the range of 15 keV to 15 MeV using the XCOM data library. The B and Si content and density of the geopolymer samples increased as the BS weight proportion increased in the geopolymer. The values of the attenuation coefficients (ACs) decreased with energy. For μ, the decrease was from 9.1533 to 0.0355 cm−1, 6.7486 to 0.0374 cm−1, 10.2964 to 0.0396 cm−1, and 10.7722 to 0.0414 cm−1, while for μρ, it was 5.3217 to 0.0206 cm2 g-1, 5.3860 to 0.0206 cm2 g-1, 5.3627 to 0.0206 cm2 g-1, and 5.3594 to 0.0206 cm2 g-1, for G, G-10BS, G-20BS, and G-30BS, respectively. There are no significant differences between the photon energy absorption capacity of the geopolymers, especially at energies greater than 1 MeV. The photon buildup factors of the G-xBS samples have very close relative values with no clear order. The introduction of waste borosilicate glass is therefore a way of improving the photon attenuation capacity of geopolymer and, therefore, the potential of shielding applications of geopolymer-based concrete.

A Review of Sisal Fiber-Reinforced Geopolymers: Preparation, Microstructure, and Mechanical Properties.

The early strength of geopolymers (GPs) and their composites is higher, and the hardening speed is faster than that of ordinary cementitious materials. Due to their wide source of raw materials, low energy consumption in the production process, and lower emissions of pollutants, they are considered to have the most potential to replace ordinary Portland cement. However, similar to other inorganic materials, the GPs themselves have weak flexural and tensile strength and are sensitive to micro-cracks. Improving the toughness of GP materials can be achieved by adding an appropriate amount of fiber materials into the matrix. The use of discrete staple fibers shows great potential in improving the toughness of GPs. Sisal is a natural fiber that is reproducible and easy to obtain. Due to its good mechanical properties, low cost, and low carbon energy usage, sisal fiber (SF) is a GP composite reinforcement with potential development. In this paper, the research progress on the effect of SF on the properties of GP composites in recent decades is reviewed. It mainly includes the chemical composition and physical properties of SFs, the preparation technology of sisal-reinforced geopolymers (SFRGs), the microstructure analysis of the interface of SFs and the GP matrix, and the macroscopic mechanical properties of SFRGs. The properties of SFs make them have good bonding properties with the GP matrix. The addition of SFs can improve the flexural strength and tensile strength of GP composites, and SFRGs have good engineering application prospects.

Mechanical, durability and microstructural characterization of cost-effective polyethylene fiber-reinforced geopolymer concrete

Portland cement is widely used in the construction industry. Its production contributes to carbon dioxide emissions, urging the need for sustainable alternatives. The present study aims to evaluate the strength, durability, microstructural properties, and cost-effectivity of geopolymer (GP) concrete containing polyethylene (PE) fibers, with fly ash (FA), ground-granulated blast furnace slag (GGBFS), and calcium magnesium carbonate (CaMg(CO3)2 known as dolomite) as binders. PE fiber used has an ultra-high molecular weight. Six different mixtures were produced with FA, GGBFS, dolomite, and/or PE fiber. The control mix used only FA as a binder without PE fiber. Fresh and mechanical properties, including slump value, compressive strength, and split tensile strength, were determined, and non-destructive tests, such as electrical resistivity and ultrasonic pulse velocity, were conducted. The durability of GP was evaluated through initial surface absorption and capillary suction absorption tests at different curing ages. Microstructural and mineralogical characteristics were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The results revealed that the addition of PE fibers and CaMg(CO3)2 reduced the workability of GP by 30.22% in comparison with that of PE fiber along with GGBFS. Compared to the reference mix at 28 days, incorporating 20% GGBFS resulted in the highest improvement of 76.89% and 104.86% in compressive and split tensile strength, respectively. GP sample with 20% GGBFS replacement of FA presented the highest reduction of 44.4–41.63% for initial and secondary rate of absorption. SEM analysis showed that the addition of GGBFS and CaMg(CO3)2 to fiber-reinforced FA-based geopolymer mixes developed a denser and more homogenous matrix with improved mechanical behavior due to the co-existence of C−S−H and aluminosilicate gel. PE fibers improve the toughness properties by helping to absorb energy and bridging cracks. The development of a stronger matrix was characterized by C−S−H, calcium aluminate oxide (carbonate) hydroxide (C4AHx) and quartz. A one-way ANOVA analysis and cost analysis demonstrate the cost-effectiveness of partially replacing FA with CaMg(CO3)2 and GGBFS in PE fiber-reinforced GP concrete.

Geopolymer synthesis and performance paving the way for greener building material: A comprehensive study

Ordinary Portland Cement (OPC) is renowned for its robustness and endurance in construction, but its manufacturing process incurs substantial energy consumption and leads to significant carbon dioxide emissions. Geopolymers (GP), conversely, represent a synthetic material derived from industrial by-products like calcined materials and slag. This study employs a diverse array of techniques to optimize the formulation of geopolymers and to evaluate their initial state (slump, reactivity) and mechanical characteristics (mechanical strength, density). Materials used are a combination of metakaolin (MK), granulated blast furnace slag (GBFS), and potassium silicate (K2SiO3) as an alkaline reagent (AR). The findings indicate that geopolymers exhibit strength akin to that of Portland cement (even better at early ages, between +16% to +88% higher), thereby positioning it as a credible substitute. The examination of the microstructure through methods such as nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Thermogravimetric analysis (TGA) reveals that the synthesized material possesses a stable interconnected polymeric 3D-structure. Furthermore, mercury porosity analysis demonstrates the presence of finer pores (nanometric) consistent with a densely packed and closely-knit micelle structure. This study demonstrates that geopolymers blend comprising calcined earth, metakaolin, and slag holds promise as a viable alternative to OPC.

Development and Properties of Low-Calcium Fly Ash-Based Geo polymer Concrete

The main objective of this current study is to develop a cement free concrete material because of the green house effect during the manufacture of cement. It is reported that every one tonne production of cement emits one tonne carbon dioxide which causes global warming and in broad sense disturbs the entire ecological system. It results the promotion of geopolymer concrete where silica and alumina will bind together with alkaline solution during the process of polymerization. The researchers taken greater initiatives in geopolymer concrete there is no specific study related to the mix design because of commercialization and patenting. Hence the authors interested in identifying specific mix design using trial proportion of low calcium fly ash and alkaline solutions (sodium silicate and sodium hydroxide). This investigation deals suggested that pozzolans such as blast furnace slag might be activated using alkaline liquids to form a binder and hence totally replace the use of OPC in concrete. In this scheme, the main contents to be activated are silicon and calcium in the blast furnace slag. The main binder produced is a C-S-H gel, as the result of the hydration process.

EXPERIMENTAL INVESTIGATION ON STUDYING THE FLEXURAL BEHAVIOUR OF GEOPOLYMER CONCRETE BEAM UNDER FIXED BOUNDARY CONDITION

Geo polymer concrete is one of the emerging construction material as a substitute for conventional cement concrete, eliminating the usage of OPC. This work is aimed to cast and testing of geo-polymer beam elements with restrained edge condition. The size of beam is 1m x 1m x 0.05 m. By using yield line theory, the moment of resistance and maximum deflection under flexural loading are calculated for the of GPC beam. Reinforcement details of these beam are calculated using ultimate load method as per IS code provisions. Geopolymer concrete is the greener concrete, which has the potential technology to reduce the carbon emission and lead to sustainable developments and growth of the concrete industry. During the manufacturing of ordinary Portland cement, large amount of carbon dioxide is released in the atmosphere causing not only air pollution but also highly responsible factor of global warming.

Experimental Investigation of Mechanical Properties of Geo–Polymer Concrete Using Flyash

Experimental Investigation of Mechanical Properties of Geo–Polymer Concrete Using Flyash

Thermomechanical behavior of textile-reinforced geopolymer concrete based on mineral-impregnated carbon-fibers (MCFs) composites

State-of-the-art textile reinforcements are well employed to strengthen, rehabilitate or build new structures, whilst polymeric impregnation degrades considerably in elevated temperatures or aggressive environments. Herein, mineral-based matrices are regarded as a viable and novel technique. This study introduces a methodology to manufacture 2D-textile reinforcements using mineral-impregnated carbon fiber (MCF) automatically via a pultrusion and robotic–based structuring process. The reinforcing ability of MCF textiles without and with surface modification in geopolymer (GP) concrete was compared to commercial epoxy-impregnated textiles. After thermally stimulated rapid solidification, the resulting grid-like structures were incorporated into the concrete matrix. The MCF-GP-concrete composites were evaluated regarding their load-bearing capacity from 20 °C to 200 °C. Digital Image Correlation (DIC) and μCT analysis were used to study damage processes and interphase adhesion. The results demonstrated that GP concrete components with MCF textiles exhibited superior thermal resistance and a bi-linear stress-strain behavior compared to polymer matrix composite. Dilatometry and TGA measurements provided shrinkage and dehydration evidence for the thermally induced strength decrease. The enhanced chemical compatibility achieved via GP impregnation facilitates the formation of finely distributed crack patterns with reduced crack widths, contributing to improved durability scenarios and failure behavior of textile-reinforced concrete (TRC).