Compressive strength and microstructure properties of modified concrete incorporated effective microorganism and fly ash

A Review on the Use of Self-Curing Agents and Its Mechanism in High-Performance Cementitious Materials

“…Within a few minutes, needle-like crystals of calcium sulfoaluminate hydrate, notably ettringite, develop. After a period of time, ettringite converts into monosulfate hydrate [22]. Two hours after the cementation process begins, large prismatic crystals of calcium hydroxide (CH) and tiny calcium silicate hydrates (C-S-H) fill the voids formerly filled by water and hydrated cement particles (as shown in Equations ( 1)-( 6)).…”

“…Calcium hydroxide is the second most prevalent component, contributing to approximately 25% of the total. Compared to C-S-H, it is composed of massive plate-like crystals with a lower surface area [22,25]. It contributes to the reduction of van der Waal forces and is relatively soluble in comparison to C-S-H, making the concrete reactive to acidic solutions.…”

“…Other methods mentioned include membrane curing, which retains the water within the concrete to maximize the potential hydration [3,10,13,14], steam [11,[16][17][18], and leaving formwork in place [1,15]. Nevertheless, the accelerated curing methods such as microwave curing [19][20][21], direct electric curing [22][23][24], and infrared curing [25] are used in the application of heat on fresh concrete to promote rapid cement hydration by securing early-age strength of concrete. However, a more common feature of all existing curing techniques is frequently applied to the surface of the concrete.…”

Smart Bio-Agents-Activated Sustainable Self-Healing Cementitious Materials: An All-Inclusive Overview on Progress, Benefits and Challenges

“…Moreover, the self-healing properties in concrete can be generated via the utilization of various geo-materials, polymers, and chemical admixtures [34]. Other form of self-healing properties in concrete can be achieved through the calcium carbonate precipitating microorganisms [35,36]. The ability of concrete to autonomously repair itself can be enhanced by the amalgamation of mineral admixtures and cementitious materials with expansive properties.…”

“…It was argued that the metabolic activity of the bacteria can induce the calcium carbonate precipitation, thus, filling the cracks in concrete [62]. Autonomous healing can be catalyzed by the injection of a bacterial culture onto the concrete surface [35]. Additionally, in a parking garage, the bacterial cultures were sprayed directly on the concrete surface containing several cracks [63], wherein the autonomous healing was found to substantially decrease the water permeability into the cracks, thus, preventing further decay of concrete surface.…”