Concrete completely submerged in sulfate solutions has been used as the primary study subject for the durability of concrete subjected to sulfates. On the other hand, empirical data from the field indicates that concrete exposed to sulfates may exhibit physical attack-induced surface scaling above. This study aims to study the two different types of local bacteria, (BS) and (BM), with content of 0%, 0.25%, 1%, 2.50%, and 5.00% by cement weight used in this work under curing in sulfate to examine the efficiency of bacterial self-healing of cracks for sustainable concrete in aggressive sulfate attack environments. The results show that in both curing in freshwater, FW, and sulfate, SUL, the optimum bacteria ratio was 2.5% BM, and the compressive strength improved by 43.34% for FW and 47.65% for sulfate. On the other hand, the results proved that the crack-filling and crack-repairing methods may be considered quicker than conventional methods. Moreover, a detailed conclusion about the preparation and processing of bacteria to provide the most significant content of locally accessible bacteria in Egypt, mainly when using chemical and mineral additives.

This study presents an innovative approach by combining magnetized water (MW) with Bacillus megaterium to improve the sustainability of concrete under various curing conditions. These enhancements contribute directly to reduced cement use and improved durability, both essential factors in sustainable construction. An experimental program with 27 distinct mixes analyzed variables such as the type of water (tap water/TW and two magnetization sequences/MW1 and MW2), bacterial dosage (0%, 2.5%, and 5% relative to cement weight), and curing methods (traditional water curing/C1, thermal shock/C2, freeze–thaw/C3). The primary discovery is a synergistic relationship between MW and bacteria: the MW1 treatment (1.5 T followed by 0.9 T) paired with a 2.5% bacterial dosage significantly improved the mechanical and self-healing properties of the concrete. This combination led to significant improvements in workability and compressive strength, achieving an increase of as much as 46.5% compared to the control. There was also an impressive recovery of strength in pre-cracked specimens, particularly under thermal shock curing (C2), where some healed cubes exceeded the strength of the uncracked ones. On the other hand, a 5% bacterial dosage was less effective, often resulting in reduced returns due to variations in microstructure. SEM and XRD analyses confirmed a more compact matrix and increased calcite precipitation with 2.5% bacteria, illustrating the combined effects of microbial activity and microwave treatment for sustainable concrete.

Concrete poses many environmental and economic problems due to its heavy reliance on natural resources. The objective of this study was to explore the potential of utilizing recycled materials, specifically waste glass powder and demolition sand, to assess their effectiveness in reducing the formation of delayed ettringite and consequently enhancing the strength of sustainable concrete. This study assesses the combined effects of waste glass powder and demolition sand on stable, sustainable concrete under sulfate exposure. A comprehensive experimental program included 23 mixes using different types of fine aggregate in concrete: standard sand, demolition sand, and mixes with 10–30% ground glass fines replacing Portland cement (PC). Also, the effects of added sodium sulfate and gypsum (1%, 3%, and 5%) on compressive, tensile, and flexural strengths were analyzed by conducting mechanical tests at 7, 28, and 56 days. Finally, SEM, EDS, and XRD were conducted to analyze the microstructures of the concrete mixes. Using gypsum and sodium sulfate provides sulfate ions to study their effects on Delayed Ettringite Formation and mechanical performance. The results of the present work showed that the optimal mix (20% glass powder with 1–3% gypsum) achieved a 21% increase in 28-day compressive strength and a denser microstructure with reduced microcracking. Gypsum showed more stable behavior under the tested conditions compared with sodium sulfate. The microstructure studies supported this conclusion and further demonstrate that optimal amounts of glass result in a denser concrete matrix with less cracking, which is used much more effectively.

The combined use of ceramic waste powder (CWP) as a supplementary cementitious material and magnetized water (MW) as mixing water represents a promising strategy for producing sustainable concrete with reduced cement consumption while maintaining mechanical performance and durability. However, the synergistic effects of burnt ceramic waste powder (BCWP) and unburnt ceramic waste powder (UBCWP) combined with MW, particularly under aggressive environmental conditions, remain insufficiently investigated. This study evaluates the influence of BCWP and UBCWP, used as partial replacements for ordinary Portland cement (OPC) at replacement levels of 10%, 20%, and 30% by weight, together with conventional tap water (TW) and MW produced using a dual-field magnetic device (0.9 T and 1.5 T). A total of fourteen concrete mixtures were investigated through compressive strength tests at 7, 28, and 120 days; indirect tensile and flexural strength tests at 28 and 120 days; sulfate resistance after 120 days of MgSO₄ immersion; residual strength after thermal exposure at 200 °C; and microstructural characterization using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The results indicate that increasing the CWP replacement level progressively reduced the mechanical properties of concrete; however, MW consistently mitigated these reductions by promoting cement hydration and producing a denser cementitious matrix. The mixture containing 20% BCWP with MW achieved a 120-day compressive strength comparable to that of the TW control, demonstrating that cement consumption can be reduced without compromising structural performance. Furthermore, MW mixtures exhibited significantly improved durability, with compressive strength losses of only 16–28% after sulfate attack compared with up to 42% for TW mixtures, and 1–13% after thermal exposure compared with up to 53% for TW mixtures. SEM and XRD analyses confirmed the development of denser microstructures with enhanced C–S–H gel formation in MW–CWP concretes. Overall, the findings demonstrate that the synergistic combination of ceramic waste powder and magnetized water provides an effective strategy for producing sustainable concrete with enhanced long-term mechanical performance, improved durability under aggressive environmental conditions, and reduced environmental impact.