The 21st century has witnessed a substantial increase in the demand for construction materials, mainly influenced by the growing population. This increase in demand has resulted in higher prices for these materials and has also placed considerable burdens on environmental resources, prompting the search for eco-friendly and economically viable alternatives such as geopolymer materials to replace traditional materials like cement. The benefits of geopolymer materials as substitutes for cement in concrete extend beyond their exceptional durability. Initially, geopolymer was introduced to address the environmental impact arising from carbon dioxide emissions and the substantial consumption of fossil fuels through the production of cement. The current review investigates recent advances regarding the durability characteristics of geopolymer materials. This includes aspects such as water absorption, temperature resistance, sulfuric acid resistance, sulfate resistance, chloride ion penetration, and freeze–thaw resistance, among others. The results of this review highlight geopolymer concrete’s enhanced durability over traditional cement-based concrete. Furthermore, this review offers recommendations and outlines potential research avenues for further exploration of geopolymer concrete.

Geopolymer concrete (GPC) is a novel and environmentally friendly type of concrete that eliminates the use of cement, resulting in a significant reduction in carbon emissions and a more sustainable construction material. Alkaline activators are used in GPC to achieve rapid strength development. The most popular alkaline activators are sodium/potassium silicate and sodium/potassium hydroxide, which are known contributors to carbon emissions, hence limiting the advantages of GPC; therefore, reducing the amount of these alkaline activators that contribute to carbon emissions is necessary for developing a more sustainable geopolymer concrete. In this study, the influence of the variation in sodium hydroxide molarities on the performance of fly ash/sugarcane bagasse ash-based-geopolymer concrete was investigated. The different molarities used were 10 M, 12 M, 14 M, and 16 M sodium hydroxide solutions. In addition, the effect of sugarcane bagasse ash content (0%, 5%, 10%, 15%, and 20%) on the fresh and hardened geopolymer concrete properties were examined. The slump test, compression test, split tensile test, and flexure test were conducted on the cast samples. The results of this study showed that raising the concentration of NaOH from 10 M to 16 M while maintaining a sodium silicate to sodium hydroxide ratio of 2.5 resulted in a 3.75–10.2% improvement in compressive strength after 28 days. It is worth noting that, even at a concentration of 10 M, the concrete still achieved high strength.

The need for concrete is increasing exponentially due to the growing population and fast urbanization. The primary constituent in concrete is ordinary Portland cement (OPC). Producing cement involves a significant quantity of embodied energy and leads to the release of greenhouse gases. Geopolymer concrete (GPC) was created to address the adverse environmental effects of carbon dioxide emissions (CO₂) and the overdependence on fossil fuels in cement production. In addition to reducing environmental consequences, geopolymer concrete shows outstanding resistance to higher temperatures compared to OPC concrete, which maintains temperatures up to 1200 °C. This review investigates the field of GPC, focusing on its ability to withstand high temperatures. It briefly reviews geopolymer concrete's mechanical properties at high temperatures. It has been observed that residual compressive strength, which is essential in high-temperature GPC studies, generally increases to 150–350 °C but decreases beyond 400 °C because of microcrack formation. Moreover, enhanced tensile strength is demonstrated up to 300 °C, with a noticeable decrease above 800 °C. This study emphasizes the potential of geopolymer concrete for improving fire protection measures in the building industry.

Portland cement plays a vital role in construction and building projects. However, its manufacturing process releases detrimental pollutants and contributes to climate change. The environmental concerns linked to the manufacturing of conventional Portland cement, such as its high energy demands, raw material consumption, and significant CO2 emissions, have prompted the need to look for alternatives such as geopolymer or green concrete. In addition, indiscriminate disposal of waste might have a detrimental effect on the environment. This paper investigates the mechanical and microstructural properties of geopolymer concrete incorporating fly ash and sugarcane bagasse ash as primary constituents. Sugarcane bagasse ash (SCBA) was employed as a partial substitute for Fly Ash (FA), with varying proportions ranging from 5% to 20% with increments of 5%. Alkaline activators utilized were NaOH (14M) and Na2SiO3, with a ratio of 1.5. Various tests, including the slump test, compressive strength test, splitting tensile strength test, and flexural strength test, were performed. The microstructural characteristics were assessed by scanning electron microscopy (SEM), energy dispersive analysis (EDS), and X-ray diffraction analysis (XRD). The results revealed that adding sugarcane bagasse ash influenced the workability of geopolymer concrete while enhancing its mechanical properties. The research findings have shown that the mixture comprising 5% SCBA has the greatest compressive strength of 64 MPa. Doi: 10.28991/CEJ-2024-010-04-018 Full Text: PDF