Biomineralized self-healing concrete is a type of concrete that, during its service life, induces the generation of calcium carbonate through the participation of microorganisms or active enzymes, thereby achieving self-repair of cracks at different times. Self-healing concrete based on biomineralization can achieve sustainable crack repair and could enhance the strength and extend the service life of buildings. This article comprehensively analyzes the latest progress in bio-self-healing concrete, including microbial-based self-healing, enzyme-induced calcium carbonate precipitation (EICP), microcapsule-loaded microbial in situ remediation, and bio-inorganic mineral synergist self-healing technology. The maximum repairable width of the crack is 2.0 mm, and concrete strength can be increased by 135%. These methods offer new insights and strategies for the repair of concrete cracks, providing fundamental knowledge for the later application of intelligent engineering of bio-self-healing concrete and the analysis of micro-interface mechanisms. At the same time, they clarify the practical possibility of microbial technology in building materials science and engineering and offer key theoretical support for the long-term development of China’s construction industry.

Cement-based self-leveling mortar (CSL) is a special building material that utilizes cement as the main cementitious component, combined with a variety of admixtures. Its self-leveling characteristics enable it to effectively level and fill uneven surfaces. Additionally, the innovative green CSL developed from industrial by-products can further enhance both environmental and economic benefits. This paper systematically reviews the use of admixtures and industrial by-products in the production of CSL. The main findings include the following: (i) compared to the international ISO standard, China’s standard JC/T 985 provides more detailed testing parameters regarding fluidity, mechanical properties, and shrinkage; (ii) the effect of additives on CSL is affected by its molecular weight and structure, and high molecular weight improving the workability of the additives; (iii) industrial by-products have been effectively incorporated into CSL, leading to a reduction in reduced greenhouse gas emissions and a decreased environmental impact; (iv) macro and microanalysis results of different green CSLs show that industrial by-product gypsum has the greatest potential for application in CSL. Based on these findings, this paper offers valuable reference data for the use of admixtures and industrial by-products in CSL. Furthermore, it contributes innovatively to the sustainable development of infrastructure construction.

This study investigates the effect of γ-aminopropyltriethoxysilane (KH550)-functionalized nano-active Al₂O₃ (KH-Al) on the properties of gypsum-based self-leveling mortar (GSL) prepared from industrial by-product gypsum. First, the effects of incorporating KH-Al at dosages of 0.05%, 0.1%, 0.25%, 0.5%, and 1% on the fluidity, setting time, and mechanical properties of GSL were analyzed. Subsequently, using X-ray diffraction (XRD), hydration heat analysis, thermogravimetric analysis (TG), and scanning electron microscopy (SEM), the influences of the nanomaterial on the mortar’s morphology, hydration characteristics, and crystal forms of hydration products were thoroughly examined. Finally, by comparing the modified GSL with ordinary GSL, the mechanism of KH-Al’s action on GSL was elucidated. The results demonstrate that nano-active Al₂O₃ modified with KH550 exhibits excellent dispersibility in the GSL paste. As the dosage of KH-Al increases, both the fluidity and setting time of GSL decrease. Upon incorporating KH-Al, the mechanical properties of GSL initially improve and then decline, with optimal mechanical performance observed at a 0.5% KH-Al addition. However, when the KH-Al dosage exceeds 0.5%, excess nano-active Al₂O₃ causes nanoparticle agglomeration, which impedes the hydration process. The nucleation effect of KH-Al promotes the formation of CŜH₂ and AFt, refines the crystals of hydration products, and enhances the phase transformation efficiency of the mortar. These findings indicate that KH-Al has significant potential to improve the mechanical strength and hydration kinetics of gypsum mortar and provide theoretical support for the application of nanomaterials in gypsum building materials.