This systematic literature review (SLR) aims to present and analyze the recent research on the effect of recycled glass (RG) on the durability of concrete applications in terms of transport properties, chemical attack, alkali-silica reaction (ASR), and freeze/thaw (FT). RG could be utilized in concrete as a replacement or addition in three forms, namely glass powder (GP), glass aggregate (GA), and glass fiber (GF). The methodology of this study was based on a criterion for the selection process of reviewed studies to assess and synthesize the knowledge of the durability of RG in concrete. The articles were assessed and screened, then 114 review articles were selected. The direction of utilization of RG in concrete depends on the type, particle size, and pozzolanic performance. The valorization of RG had a positive impact on the durability of concrete; however, the mutual synergy of multiple substitutions with glass also had better results. Nowadays, fine glass aggregate (FGA) could be promoted to be used as a partial substitute for sand due to the easiness of recycling. Furthermore, GF is strongly encouraged to be used in fiber concrete. An analytical framework that highlights the durability improvement of glass-modified concrete is presented. The results suggested that it is technically feasible to utilize glass as a part of concrete in the production of durable concrete. It provides a higher resistance to transport properties and chemical attacks by providing an extended lifespan. In addition, RG plays a great role in FT action in cold climates while it does not have a significant impact on ASR, provided refinement of glass results in the reduction of ASR and thus overcomes the expansion and cracks of concrete. However, up to 20% GP and up to 30% fine glass aggregate (FGA) could be replaced with cement and aggregate, respectively, to achieve a positive effect on durability based on the W/C ratio provided, not compromising the strength.

The paper reviewed the current perspectives on the development of carbon dioxide (CO₂) sequestration through its process conversion into calcite. The process occurs in either geological or biological systems. However, geological sequestration is an expensive process, which is slow in comparison to bio-sequestration. Recently, the bio-sequestration of atmospheric CO₂ into the soil using microorganisms such as algae has been investigated. However, the algae cannot be used in the bio-concrete due to their nature as phototrophic organisms. In contrast, bacteria are the most potent organisms in bio-concrete technology. The use of bacterial species in the bio-aerated concrete bricks (B-ACB) and its potential to bio-sequestrate CO₂ represents a future strategy to reduce high CO₂ pollution. Bacterial cells can capture CO₂ by accelerating the carbonation processes, which convert CO₂ into calcium carbonate (CaCO₃) via carbon anhydrase and urease enzymes. The present paper aimed to highlight and discuss the applicability of bacteria in the B-ACB for capturing and storing CO₂. It is evident from the literature that the new trends to use bio-concrete might contribute to the reduction of CO₂ by accelerating the carbonation process and strengthening the B-ACB.

Sustainable wastewater treatment is one of the biggest issues of the 21st century. Metals such as Zn²⁺ have been released into the environment due to rapid industrial development. In this study, dried watermelon rind (D-WMR) is used as a low-cost adsorption material to assess natural adsorbents’ ability to remove Zn²⁺ from synthetic wastewater. D-WMR was characterized using scanning electron microscope (SEM) and X-ray fluorescence (XRF). According to the results of the analysis, the D-WMR has two colours, white and black, and a significant concentration of mesoporous silica (83.70%). Moreover, after three hours of contact time in a synthetic solution with 400 mg/L Zn²⁺ concentration at pH 8 and 30 to 40 °C, the highest adsorption capacity of Zn²⁺ onto 1.5 g D-WMR adsorbent dose with 150 μm particle size was 25 mg/g. The experimental equilibrium data of Zn²⁺ onto D-WMR was utilized to compare nonlinear and linear isotherm and kinetics models for parameter determination. The best models for fitting equilibrium data were nonlinear Langmuir and pseudo-second models with lower error functions. Consequently, the potential use of D-WMR as a natural adsorbent for Zn²⁺ removal was highlighted, and error analysis indicated that nonlinear models best explain the adsorption data.

This study carried out a comprehensive review to determine the carbonation process that causes the most deterioration and destruction of concrete. The carbonation mechanism involved using carbon dioxide (CO₂) to penetrate the concrete pore system into the atmosphere and reduce the alkalinity by decreasing the pH level around the reinforcement and initiation of the corrosion process. The use of bacteria in the concrete was to increase the pH of the concrete by producing urease enzyme. This technique may help to maintain concrete alkalinity in high levels, even when the carbonation process occurs, because the CO₂ accelerates to the concrete and then converts directly to calcium carbonate, CaCO₃. Consequently, the self-healing of the cracks and the pores occurred as a result of the carbonation process and bacteria enzyme reaction. As a result of these reactions, the concrete steel is protected, and the concrete properties and durability may improve. However, there are several factors that control carbonation which have been grouped into internal and external factors. Many studies on carbonation have been carried out to explore the effect of bacteria to improve durability and concrete strength. However, an in-depth literature review revealed that the use of bacteria as a self-healing mechanism can still be improved upon. This review aimed to highlight and discuss the possibility of applying bacteria in concrete to improve reinforcement concrete.

This research aimed to optimize the compressive strength of bio-foamed concrete brick (B-FCB) via a combination of the natural sequestration of CO₂ and the bio-reaction of B. tequilensis enzymes. The experiments were guided by two optimization methods, namely, 2^k factorial and response surface methodology (RSM). The 2^k factorial analysis was carried out to screen the important factors; then, RSM analysis was performed to optimize the compressive strength of B-FCB. Four factors, namely, density (D), B. tequilensis concentration (B), temperature (T), and CO₂ concentration, were selectively varied during the study. The optimum compressive strength of B-FCB was 8.22 MPa, as deduced from the following conditions: 10% CO₂, 3 × 10⁷ cell/mL of B, 27 °C of T and 1800 kg/m³ of D after 28 days. The use of B. tequilensis in B-FCB improved the compressive strength by 35.5% compared to the foamed concrete brick (FCB) after 28 days. A microstructure analysis by scanning electronic microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction analysis (XRD) reflected the changes in chemical element levels and calcium carbonate (CaCO₃) precipitation in the B-FCB pores. This was due to the B. tequilensis surface reactions of carbonic anhydrase (CA) and urease enzyme with calcium in cement and sequestered CO₂ during the curing time.