Upcycled geopolymer concrete incorporating GFRP waste powder: Sulfate resistance and machine learning-based strength prediction

Evaluation of freeze-thaw resistance of geopolymer concrete incorporating GFRP waste powder

Assessment of recycling use of GFRP powder as replacement of fly ash in geopolymer paste and concrete at ambient and high temperatures

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

Geopolymers are recognised for their environmental benefits and excellent chloride and sulfate resistance. However, information on the material characteristics and bond behaviour of geopolymers based on fly ash (FA) and slag is still relatively scarce. This paper presents a comprehensive study on the integration of two modern construction materials – geopolymer concrete (GPC) based on FA and ground granulated blast-furnace slag and glass-fibre-reinforced polymer (GFRP) bars. The aim of the study was to assist concrete structural design by identifying the key preparation parameters such as hardening and bond behaviour. It was found that the hardening of the GPC was much faster than that of ordinary Portland cement (OPC) concrete at an early age and the stress–strain curves, elastic moduli and splitting tensile strengths of the GPC were accurately predicted by existing models developed for OPC concrete. The GFRP bars in the GPC outperformed those in the OPC concrete in terms of normalised bond strength. The GPC reinforced with both GFRP and steel rebars exhibited similar bond–slip curves to the OPC concrete. Overall, the behaviour of the GFRP-reinforced GPC was found to be analogous to that of the OPC concrete while providing adequate compressive, tensile and bond strength for the construction of foundations of low-rise buildings.

A novel method is developed for reusing the waste glass fiber-reinforced polymer (GFRP) powder as a precursor in geopolymer production. Several activation parameters that affect the workability and strength gain of GFRP powder-based geopolymers are investigated. The results of an experimental study reveal that the early strength of GFRP powder-based geopolymer pastes develops slowly at ambient temperature. The highest compressive strength of GFRP powder-based geopolymer pastes is 7.13 MPa at an age of 28 days. The ratio of compressive strength to flexural strength of GFRP powder-based-geopolymers is lower than that of fly ash and ground granulated blast furnace slag (GGBS)-based geopolymers, indicating that the incorporation of GFRP powder can improve the geopolymer brittleness. GGBS is incorporated into geopolymer blends to accelerate the early activity of GFRP powder. The binary geopolymer pastes exhibit shorter setting times and higher mechanical strength values than those of single GFRP powder geopolymer pastes. The GGBS geopolymer concrete mixture with 30 wt% GFRP powder displayed the highest compressive strength and flexural strength values and was less brittle. The developed binary GFRP powder/GGBS-based geopolymers reduce the disadvantages of single GFRP powder or GGBS geopolymers, and thus, offer high potential as a building construction material.

The current investigation focuses on developing a finite element (FE) model using ansys parametric design language (APDL) for fiber‐reinforced geopolymer concrete (GPC). In this study, fly ash and ground granulated blast furnace slag based GPC were used, and glass fiber‐reinforced polymer (GFRP) was considered for strengthening the T‐beam. To overcome the issue of providing fiber‐reinforced polymer on the soffit of existing beams, the study was done on the effect of GFRP on the flexural strength of the side‐bonded flexure‐deficient T‐beam. GFRP was provided in three layers through the application of epoxy. All the specimens were tested under a two‐point load to determine flexural strength. The FE model was validated through the experimental results we obtained in the laboratory. The validated models were used for further parametric studies of T‐beams with varying compressive strength, steel reinforcement ratio, and GFRP laminate size. The findings illustrated that finite element modeling is effective in predicting the structural response of T‐beams constructed with GPC, ensuring accurate results.

This study explores the durability of green cementitious material of geopolymer concrete. Geopolymer concrete is produced from the polycondensation reaction of aluminosilicate materials (fly ash, Ground Granulated Blast furnace Slag (GGBS)) with alkaline activator solutions. Geopolymer concrete has excellent mechanical properties and its production requires low energy and results in low levels of CO2 emission. Due to the high demand for river sand, manufactured sand is used as a replacement material in geopolymer concrete under ambient curing conditions. In this study, the durability of G30 grade geopolymer concrete has been investigated using tests acid resistance, water absorption, sulphate resistance, Rapid Chloride Penetration Test (RCPT), and rate of absorption (Sorptivity) test. The sulphuric acid, sodium sulphate, and water absorption tests were carried out at 28 days, 56 days, and 90 days for both the geopolymer and the conventional concrete. The reduction percentage in water absorption and compressive strength loss was found to be better in geopolymer concrete than in conventional concrete. Geopolymer concrete’s chloride penetrability and rate of absorption were analogous to conventional concrete. Regression analysis for geopolymer and conventional concretes in the rate of absorption test showed a good relationship between absorption and the square root of time.

Behavior of GFRP bar reinforced geopolymer concrete filled GFRP tube columns under different loading conditions

Recycling and optimum utilization of GFRP waste into low-carbon geopolymer paste for sustainable development

Experimental investigation of GFRP bar bonding in geopolymer concrete using hinged beam tests

Cement is an essential material for concrete, which is mostly used worldwide second to the consumption of water. Due to the emission of CO2 into the atmosphere, the alternative material of geopolymer concrete was used. In this research work, silica and alumina content such as ground granulated blast furnace slag (GGBS), fly ash, and triggered by alkali activator solutions were used in geopolymer concrete. Due to the dwindling of river sand, alternative material of manufactured sand (M-Sand) was considered. To avoid corrosion problems in reinforced concrete structures, glass fibre reinforced polymer (GFRP) and basalt fibre-reinforced polymer (BFRP) bars were used as an alternative material for steel reinforcement in this work. As per the code, IS: 10262, the concrete mix design of M30 grade has arrived for the control mix and the same proportion was adopted for geopolymer concrete. Six beams of geopolymer and a concrete control beam of 100 × 160 × 1700 mm were cast and examined under a four-point cyclic load. Cyclic load results were compared with static load under ambient curing. Residual deflection, moment capacity, energy dissipation, and stress–strain behaviour results were compared and discussed. A sudden shear and premature failure were observed in FRP beams under static and cyclic bending tests.

Significant issue in reinforced concrete (RC) structures is corrosion of steel. High alkalization of cement matrix, low permeability, and sufficient cover plays an important role to shield from corrosion of steel. There is a replacement material for steel is fiber‐reinforced polymer (FRP) bars as reinforcement. The FRP bars are nonconductive and durable material and they are composited from fibers and polymers matrix. In this study, new technology geopolymer concrete (GC) was used along with glass fiber‐reinforced polymer (GFRP) and basalt fiber‐reinforced polymer (BFRP) bars. GC is produced from industrial by‐product materials such as fly ash and ground granulated blast furnace slag (rich in silica and alumina) and treated as sustainable material. The long term durability of many RC structures affects drastically by the reinforcement corrosion. Main aspect of bond behavior is tension stiffening as it has capability to control the reinforcement to shift the tensile stresses to concrete. This paper evaluates the bond strength between the GC reinforced with GFRP/BFRP and the results were evaluated with conventional concrete (CC) reinforced with steel. The pullout test method was used to determine the bond between FRP and steel bars with the surrounding concrete based on IS: 2770 (part I)‐1967. The comparison of bond strength GC with FRP almost same as CC with steel. The tension test and double shear test were also carried out in FRP and steel bars based on IS 432–1982 and 5242–1979, respectively.

Experimental study on the effect of matrix on the flexural behavior of beams reinforced with Glass Fiber Reinforced Polymer (GFRP) bars

Analytical load-moment (P-M) interaction diagrams of GFRP bar reinforced circular geopolymer concrete columns

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.