微生物诱导形成的碳酸镁胶结松散颗粒研究

Loose Particles Cemented by Microbially Induced Magnesium Carbonate

微生物诱导形成的方解石可以把松散颗粒胶结成具有一定力学性能的整体,该特性被广泛用于修复水泥基材料表面缺陷,处理地基等领域。为探明微生物诱导形成的其他碳酸盐沉淀是否具有方解石相似特性,本文对微生物诱导形成的碳酸镁胶结松散砂颗粒的效果进行研究。通过对未掺加微生物和掺加微生物的试样进行对比发现,在采用相同成型工艺、相同注入次数下,微生物诱导形成的碳酸镁同样具有胶结松散颗粒的作用;本文采用X射线衍射和扫描电镜对微生物诱导形成的白色沉淀物进行分析,结果表明,微生物诱导形成的白色沉淀物为菱镁矿型碳酸镁,呈针棒状;经过力学性能测试,微生物诱导形成的碳酸镁胶结松散砂颗粒砂柱(微生物砂柱)具有一定的抗压强度。

Loose particles could be cemented by the microbial induced calcite into a bio-sandstone with a certain mechanical strength. This technique could be used to repair the surface defects in the cementitious materials and in the treatment of foundations. In order to determine whether other carbonate minerals induced by microbe have the similar properties as the calcite, loose particles were cemented by microbially induced magnesium carbonate. The samples with bacteria and without bacteria are compared, and it is shown that the microbially induced magnesium carbonate could also have the same cementation function while adopting the same molding process and the injection time. In addition, the microstructure of the microbially induced white precipitate, the bio-sandstone was analyzed by X-ray diffraction and scanning electron microscopy and. was shown to be the magnesite with the morphology of needles. The mechanical test shows that the microbial induced magnesium carbonate cementation of unconsolidated sand particles in the form of sand column （bio- sandstone） has a certain compressive strength.