一种基于微生物沉积的水泥砂浆表面改性技术

A new surface-modified technology of cement mortar using calcium carbonate biodeposition

某些微生物能诱导沉积出具有胶凝和矿化作用的碳酸钙,可以用来修复和密实水泥基材料。但是目前微生物沉积技术工艺复杂,成本高,不利于推广和工程应用。尝试采用水泥砂浆粉作为覆膜载体,利用巴斯德芽孢杆菌对水泥砂浆进行表面处理。研究结果表明,采用该方法能使巴斯德芽孢杆菌在水泥试块表面诱导沉积出碳酸钙,有效减少水泥砂浆的吸水性能。当微生物采用含有尿素的培养基培养时,表面改性后的水泥砂浆吸水系数降低了58%。采用压汞测试仪(MIP)分析了处理前后水泥试块表层的孔隙率以及孔结构特征。发现采用巴斯德芽孢杆菌处理后,样品孔隙率显著降低,大孔的含量显著减少,当微生物采用含有尿素的培养基培养时,总孔隙率降低了40%。X射线衍射仪(XRD)和场发射扫描电镜(SEM)分析表明,经微生物技术处理后水泥试块内部的孔洞和裂缝被球霰石和方解石填充。

The paper presents a new surface modification of cement mortar using biodeposition involving a meth- od employing sporosarcina pasteurii （bacillus pasteurii） bacteria and using cement mortar power as covering lay- er. It was possible to obtain reduction in water absorption of cement mortars. The effect was more visible in case of using nutrient medium containing urea, and the coefficient of capillary suction of the treated cement mortar was reduced by 58%. Presence of spherical and columnar vaterite and calcite calcium carbonate crystals filling-voids in cement mortar was confirmed by observations under SEM and XRD. The total porosity reduced by 40% was demonstrated by using mercury intrusion porosimetry （MIP）.