Experimental Study on Mechanical Properties of Cured Sand Combined with Plant-Based Bio-cement (PBBC) and Organic Materials

Bio-cement is a green and energy-saving building material, which has received wide attention in the field of ecological environment and geotechnical engineering in recent years. The aim of this study is to investigate the improvement effect of plant-based bio-cement (PBBC) in synergistic treatment of sand with organic materials, to highlight the effective use of tap water in PBBC, and to analyze the crack evolution pattern during the damage of specimens by using image processing techniques. The results showed that tap water can be used as a solvent for PBBC instead of deionized water. The characteristic trend of urease solutions prepared at different temperature environments was obvious, and the activity value of urease solution with low concentration is positively correlated with the ambient temperature, although the activity value is not high, it is not easy to inactivate. The incorporation of organic materials increased the peak stress up to 1809.30 kPa compared to the specimens modified only by PBBC. The damage of the specimens under uniaxial compression consisted of four stages: compaction, elastic deformation, pre-peak brittle damage and post-peak macroscopic damage. The corresponding crack evolution is the interpenetration of small-sized cracks into large-sized main cracks. The large-sized main cracks transform into penetration cracks before damage, and the small-sized cracks are distributed around the penetration cracks. The crack evolution parameters obtained by MATLAB processing are positively correlated with the strain.