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Researchers are increasingly becoming fascinated by the possibilities of utilizing natural fibre, which is a byproduct of production processes, as an addition in concrete. This fibre exhibits a low density and is amenable to chemical changes. The primary aim of this research study is to examine the influence of agave cantula roxb. fibre (ACRF) in low-density foamed concrete (FC) after being subjected to different doses of alkali treatment using sodium hydroxide (NaOH). Various weight fractions of treated ACRF were employed in the FC mix, namely 0% (as the control), 1%, 2%, 3%, 4%, and 5%. FC with a density of 1060 kg/m3 was produced and subsequently tested. The three types of strength properties that have been evaluated and analysed included flexural, tensile, and compressive strengths. The findings from this study have revealed that the inclusion of 3% of treated ACRF in FC yields highly favourable results in relation to strength properties. The use of treated ACRF improves the FC’s strength characteristics, particularly its bending and tensile strength, by bridging microscopic cracks and filling up gaps. It is noteworthy to emphasize that accumulation and unequal dispersion of ACRF are possible if the weight fraction of ACRF applied above the optimal value of 3% which led to decrease in FC’s strength properties. This exploratory work will lead to a better understanding of the potential applications of treated ACRF in FC. It is critical to encourage the long-term development and implementation of FC products and technology.

The use of lightweight aggregate can bring advantages to the construction field. Lightweight aggregate has been used due to its lower density and can reduce the dead load applied to the structural elements. Due to the number of natural resources, such as natural aggregate having decreased, producing lightweight aggregate from industrial waste materials can overcome the problem. Different methods produce lightweight aggregates, such as sintering, cold bonding, and autoclaving. From earlier studies, spherical sintered lightweight aggregate can manufacture structural concrete. Using artificial lightweight aggregate in concrete can achieve the minimum strength requirement of structural concrete and has been applied in the construction field. The properties of lightweight aggregate, such as specific gravity, water absorption, crushing strength, and impact value, are reviewed. Besides that, the mechanical and thermal properties review is also important for using lightweight aggregate in concrete. The review also indicates that aggregate produced using the cold bonding method and autoclaving method potential can be used in the concrete.

Current development consists of a high-rise building and heavy traffic load demands for soil with good engineering properties. Lateritic soil is commonly treated with Ordinary Portland Cement (OPC) to improve its engineering properties in order to enhance its load bearing capacity. The production of OPC however emits a large amount of carbon dioxide (CO2) into the atmosphere. Geopolymer technology has been explored as an alternative replacement for the OPC. In this research, the unconfined compressive strength (UCS) of a lateritic soil treated with fly ash (FA) based geopolymer up to 40% by weight of the dry soil and activated using combination of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) was investigated by means of unconfined compression test (UCT). The effect of different molarity of NaOH (5-20 M), FA to alkali activator (AA) ratio (1-3) and different curing temperatures to the UCS of treated soil sample are being determined. In general, as the content of FA in the soil increases, the UCS increases more than 100% and almost 400% compared to the untreated soil for room curing temperature and oven curing temperature respectively. Based on the scanning electron microscopy (SEM) result, the molarity of NaOH solution reduces the pores in the treated soil sample. The geopolymerization process combines the soil particle and makes it denser, resulting in higher UCS than the untreated soil sample.

Alkali activation for producing alkali-activated materials is noted as a complex due to involving several reactions. Due to complexity of the reactions, various techniques have been applied by past researches on monitoring the evolution of alkali-activated materials. The evolution monitored during alkali activation include internal relative humidity, structural evolution, ultrasonic evolution and heat evolution. All of these techniques provide real-time information which is significant for evaluating the reaction process of alkali activation with respected parameters applied thus will be briefly reviewed in this paper. In addition, among those techniques, due to its reliability, heat evolution is one noted as one of the most common techniques applied to elucidate the alkali activation process. Therefore, the potential of heat evolution will also be significantly highlighted in this study.

The effects of supplementary cementitious materials (SCM) on the characteristics and internal structure of synthetic aggregate made from ground granulated blast furnace slag are investigated in this study (GGBS). Due to its high pozzolanic activity, GGBS was shown to be superior to other SCM materials, enhancing both the strength and durability of synthetic aggregate. Because sintering uses a lot of energy and generates a lot of pollutants, using a cold-bonded approach to make low density lightweight aggregates is particularly significant from an economic and environmental standpoint. Thus, the utilisation of ground granulated blast furnace slag (GGBS) as a substitute material in the production of green artificial lightweight aggregate (GLA) using the cold bonding method was discussed in this work. Admixtures of ADVA Cast 203 and Hydrogen Peroxide were utilised to improve the quality of GLA at various molar ratios. The freshly extracted GLA was then evaluated for specific gravity, water absorption, aggregate impact, and aggregate crushing in order to determine the optimal proportion blend. As a result, the overall findings offer great application potential in the development of concrete (GCLA). It has been determined that aggregates with a toughness of 14.6% and a hardness of 15.9% are robust. The compressive strength test found that the GCLA has a high strength lightweight concrete of 37.19 MPa and a density of 1845.74 kg/m3. The porous features developed inside the internal structure of GLA have led to GCLA’s less weight compared to conventional concrete.

Dramatic population and economic growth result in increasing demand for concrete infrastructure, which leads to an increment of freshwater demand and a reduction of freshwater resources. However, freshwater is a finite resource, which means that freshwater will be used up someday in the future when freshwater demand keeps increasing while freshwater resources are limited. Therefore, replacing freshwater with seawater in concrete blending seems potentially beneficial for maintaining the freshwater resources as well as advantageous alternatives to the construction work near the sea. There have been few experimental research on the effect of blending water salt content on the mechanical and physical characteristics of concrete, particularly high-strength concrete. Therefore, a research study on the influence of salt concentration of blending water on the physical and mechanical properties of high-strength concrete is necessary. This study covered the blending water salinity, which varied from 17.5 g/L to 52.5 g/L and was determined on the physical and mechanical properties, including workability, density, compressive strength, and flexural strength. The test results indicate that the use of sea salt in blending water had a slight negative influence on both the workability and the density of high strength concrete. It also indicates that the use of sea salt in blending water had a positive influence on both the compressive strength and the flexural strength of high-strength concrete in an earlystage.

This study investigates the nucleation mechanism of slag alkali activation at different solid-to-liquid ratios, focusing on kinetics, including growth rates. Heat evolution during activation was monitored, and calorimetric data were analyzed using the Johnson–Mehl–Avrami–Kolmogorov model. Compressive strength and phase evolution (via wide-angle X-ray scattering) were correlated with heat evolution to enhance understanding of reaction mechanisms in alkali-activated material formation. This is essential for producing alkali-activated slag that meets standard requirements for construction applications. Results showed that the highest heat evolved (–360.60 J/g) did not correlate with the best strength performance (22.69 MPa at 1 day and 25.83 MPa at 3 days), since the lowest cumulative heat (–226.15 J/g) at an S/L ratio of 1.4 yielded the best strength. This was supported by the highest growth rate (0.1172 min–1) at this ratio. JMAK analysis indicated instantaneous nucleation with one-dimensional rod-like growth, driven by increased nucleation site availability. From the results obtained, it can be concluded that an increment in S/L ratio significantly increased nucleation and polymerization of alkali-activated slag, thereby hindering heat flow, as evidenced by the lowest total cumulative heat evolved. In addition, the highest growth rate observed corresponded linearly with the compressive strength, further confirming densification by polymeric gels formed during alkali activation.

Lightweight aggregate concrete (LWAC), produced by partially or fully replacing conventional dense aggregates with lightweight alternatives, is increasingly used in structural and building applications. Lightweight Expanded Clay Aggregate, or LECA, is a common kind of lightweight aggregate. However, due to its inherent disadvantages that include high water absorption caused by its porous structure, low mechanical strength, and high brittleness, its use in structural concrete is limited. Surface treatment of LECA has emerged as a promising strategy to improve its mechanical performance and durability, in order to overcome these limitations. Coating LECA with geopolymer-based materials made from solid waste and industrial waste that is high in aluminosilicates. These geopolymer systems can penetrate and seal the surface pores of LECA when activated by alkaline solutions to create a durable protective barrier that improves the structural integrity of the aggregate. Thus, this paper reviews the key parameters influencing the geopolymerization process including the composition and nature of the raw material, alkaline activator molarity, solid-to-liquid ratio, and curing conditions. In order to formulate long-lasting, high-strength geopolymer coatings for LECA and, subsequently, expand the use of the material in load-bearing and green structures, a comprehensive understanding of these factors is essential.

This review highlights the recent advancements in surface coatings that are crucial for fire retardancy and abrasion resistance. Developments in fire-retardant coatings have introduced formulations that enhance thermal stability and improve combustion resistance. Simultaneously, innovations in abrasive materials focus on durable, high-strength, and heat-resistant compositions suited to demanding industrial applications. These trends reveal a growing need for sustainable, high-performance alternatives to traditional materials. Geopolymers are emerging as a promising solution, environmental compatibility, and superior performance to deliver coatings that excel in both fire protection and wear resistance. This review consolidates findings across fire protection and abrasive applications, emphasizing the role of geopolymer technology in developing coatings that can withstand both fire and mechanical wear. Future directions include optimizing geopolymer formulations to further enhance their resilience, making them adaptable to varied high-demand applications.

Immunotherapies targeting PD-1/PD-L1 are now widely used in the clinic to treat a variety of malignancies. While most of the research on T cell exhaustion and PD-1 blockade has been focused on conventional αβ T cells, the contribution of innate-like T cells such as γδ T cells to anti-PD-1/PD-L1 mediated therapy is limited. Here we show that tumor reactive γδ T cells respond to PD-1 blockade in a Merkel cell carcinoma (MCC) patient experiencing a complete response to therapy. We find clonally expanded γδ T cells in the blood and tumor after pembrolizumab treatment, and this Vγ2Vδ1 clonotype recognizes Merkel cancer cells in a TCR-dependent manner. Notably, the intra-tumoral γδ T cells in the MCC patient are characterized by higher expression of PD-1 and TIGIT, relative to conventional CD4 and CD8 T cells. Our results demonstrate that innate-like T cells could also contribute to an anti-tumor response after PD-1 blockade. Immune checkpoint blockade cancer therapy has been designed to enable tumor killing by conventional αβ T cells. Here authors show that in a Merkel cell carcinoma patient showing complete response to anti-PD-1 treatment, innate-like γδ T cells that specifically recognize the tumor cells expand, and likely contribute to therapeutic success.