水泥石表面微生物沉积碳酸钙覆膜的不同工艺

DIFFERENT TREATED METHODS OF MICROBIOLOGICALLY DEPOSITED CaCO_3 LAYER ON HARDENED CEMENT PASTE SURFACE

自然界中某些微生物可以通过其自身生命活动的不断精确重复在石材表面矿化覆膜。选用了一种碳酸盐矿化菌,在实验室内人为加速模拟这一微生物矿化过程,7d内可在水泥石表面沉积出碳酸钙膜,与基材结合紧密。通过浸泡、喷涂、固载涂刷等多种工艺进行了微生物覆膜,并对覆膜层进行扫描电镜分析、厚度测量、以及覆膜后试件毛细吸水系数的对比结果发现:通过微环境的供给与优化,可以简化覆膜工艺,尤其以海藻酸钠或琼脂作为载体涂刷覆膜,其相比于喷涂法更能使菌株附着于水泥石表面生长,并在较长时间内保护菌株细胞内的酶活性。水泥石试件覆膜后毛细吸水系数可降低近90%,防护效果显著。

Some bacteria in nature can mineralize its surrounding medium to form an inorganic layer on the surface of stone material continuously and precisely by its life activity. Some accelerated experimental simulations of the microbiologically precipitation process were conducted after selecting a carbonate-mineralization microbe. The bio-deposited layer was about 100 um and bound tightly with the surface of cement pastes after treated for 7 d. The treatment methods such as immersing, spraying and brushing immobilized media were chosen to carry on microbiologically deposited layer through the contrast of scanning electron microscope analysis, layer thickness measurement, and coefficient of capillary suction of the specimens. The results show that the treatments can be simplified with micro-environment supply and optimization, especially when odium alginate and agar are used as the media brushing layer immobilized bacteria to cling to the specimen surface, which keep urease in the cells active in long term compared with the spraying method. According to the experiment results, the coefficient of capillary suction of the treated hardened cement paste is reduced by 90% and reveals an outstanding protective effect.