摘要
Abstract
Sulfate corrosion imposes a serious threat to the long-term durability of cement-based materials,therefore to investigate the mechanism of microbial induced carbonate precipitation(MICP)technology in enhancing the resis-tance of cement-based materials to sulfate erosion,the standard curing specimens(BY,BBY)and carbonation cur-ing specimens(TY,BTY)were prepared by mineralized microorganisms of Bacillus subtilis(BS)with high alka-line adaptability.The test and analysis of carbonation depth of specimen,macroscopic mechanical properties(com-pressive strength,expansion rate),microstructure,and products composition of the specimens were systematically conducted at different sulfate attack ages.The research results indicate that the addition of BS effectively improves the early performance of cement mortar specimens.Under the standard curing conditions,the initial compressive strength of specimens with added BS(BBY)increased by about 4.2％compared to the control group specimen(BY);Under carbonation curing conditions,the initial compressive strength of BTY with added BS increased by about 8.1％compared to the control group specimen(TY),indicating that the synergistic effect of carbonation curing and BS can further optimize the early strength of the material.The results of long term sulfate erosion tests have shown that BS can effectively inhibit the deterioration process of cement-based materials.Compared with the 0 day erosion,after 180 days of sulfate erosion,the compressive strength loss of the BS with added specimens decreased by 15.4％to 20.0％compared to the control group specimens,and the volume expansion rate decreased by 8.9％to 10.0％.Mi-croscopic analysis further confirms that the calcium carbonate induced by BS can effectively fill the pores of the ce-ment matrix,after 180 days of erosion,reducing the porosity of BTY and BBY specimens by 2.2％to 3.7％compared to the control group specimens TY and BY.It also delays the formation of expansive products such as gypsum and et-tringite,inhibits the growth of harmful pores,and maintains the structural stability of the cement matrix.This re-search result validates the feasibility of MICP technology,especially combined with carbonation curing,can signifi-cantly enhance the sulfate resistance of cement-based materials.This technology provides a green and reliable ap-proach for developing high durability cementitious materials with important engineering application value.关键词
MICP技术/水泥基材料/硫酸盐侵蚀/生物矿化/碳化养护Key words
microbially induced carbonate precipitation(MICP)technology/cement-based materials/sulfate erosion/biomineralization/carbonation curing分类
建筑与水利
