Development of light-weight hollow constructional materials through microbial-induced calcium carbonate precipitation

Microbial-induced calcium carbonate precipitation (MICP) is a novel technology with broad application prospects. The technology introduces bacteria and cementation media into the sand, and calcium carbonate precipitation binds the sand particles together and then forms sandstone materials. This study introduced a light-weight hollow building material constructed through MICP. The mechanical behaviors of the MICP-treated hollow samples with three different cross-sectional shapes, including circular shape in both outer and inner sections (C-C), square shape in both outer and inner sections (S-S), and square shape in outer section and circular shape in inner section (S-C) were investigated in this study. Experimental results indicated that the highest and lowest flexure strength was found in C-C and S-C samples, respectively. However, a different result was obtained in the UCS test. The S-C samples have the highest UCS, while the C-C samples achieve the lowest UCS. Meanwhile, samples were also tested to determine dry density and CaCO3 content. It was found that the dry density of MICP-treated samples significantly increased from 1670 to 1800 kg/m3, and the C-C samples had the highest CaCO3 content. It can also be found that the effects of hole size for each cross-sectional shape on the dry density and CaCO3 content are insignificant.