Lab-Scale Experiments for Soil Cementing Through Bio-Chemical Process

Abstract

Ureolytic bacteria strains of Bacillus show its ability of calcium carbonate precipitation through metabolic activity. Different studies related to self-healing concrete material were reported associated with the generated calcium carbonate of Bacillus subtilis HU58 metabolism in recent communications. In this paper, recent findings of soil cementing with a combination of such precipitated products were presented. The experiments relied on the lab-scale studies with the use of sand-clay mixture as the controlled soil specimens. Bacillus bacteria and nutrients were mixed to introduce in the sand matrix and then curing in high moisture condition. The composition and morphology of soil specimens were characterized after solidifying by FTIR, XRD, and SEM. Water percolation and mechanical stability for the physicomechanical properties were also tested with the unconventional method. Discussing the relevant results can help to figure out the next experiments in the field of geotechnical engineering. From the perspective of this study, the sustainability factor should be considered to apply this promising technique for soil stabilization and improvement and/or for the formulation of bio-brick as an alternative to sintered clay-based brick. From the perspective of this study, this technique for soil stabilization and improvement and/or for the formulation of bio-brick can be considered a promising sustainable alternative to sintered clay-based brick.

Durability Improvement of Biocemented Sand by Fiber-Reinforced MICP for Coastal Erosion Protection

“…Furthermore, because the samples’ core zone was tightly restricted, the produced fatigue stresses caused greater damage to the columns of the outer surface, resulting in the advancement of the macropores. Some biocemented specimens have been reported to have similar early surface degradation due to WD forces [ 29 ]. Additionally, the disparity among the heat expansion coefficients between the calcium carbonate and the soil material might be an added element that caused internal fatigue stresses to develop during temperature changes, resulting in carbonate bond degradation [ 30 ].…”

Eco-friendly method of biocementation for soil improvement and environmental remediation in the context of Viet Nam: a state-of-the-art review

“…It has been found that the self-healing concrete field has achieved positive results and advancements in recent years in Viet Nam [3,14,63,64]. Laboratory studies, such as those conducted in 2019 and beyond [65,66], have explored the possibility of using Bacillus subtilis (HU58) bacteria for soil cementation. Although the experiments primarily employed small soillike specimens and unconventional approaches, deviating from standardized testing methods in geotechnical engineering, significant findings were obtained, warranting further research in subsequent phases.…”