不同微生物矿化能力比较及对再生骨料吸水率影响的试验研究

Experimental study on the mineralization capacity of different microorganisms and the effect on water absorption of recycled aggregates

随着绿色环保观念的加强,微生物矿化沉积改性再生骨料技术引起国内外学者的重视。主要研究假坚强芽孢杆菌Bacillus pseudofirmus DSM8715和嗜碱芽孢杆菌H4的自身矿化效果以及对再生骨料的改性能力。通过扫描电镜(SEM)观察微生物矿化产物的微观形貌,X-衍射线(XRD)技术对矿化产物定性分析,并利用热重分析仪(TGA)进行矿化产物中碳酸钙含量分析。试验结果表明:2种微生物矿化产物均为方解石型碳酸钙晶体,嗜碱芽孢杆菌H4矿化产物中碳酸钙含量达到了94.32%,矿化系数为79.97%;而假坚强芽孢杆菌Bacillus pseudofirmus DSM8715矿化产物中碳酸钙含量仅为86%,矿化系数为68.40%。与未经微生物矿化处理的再生骨料相比,用嗜碱芽孢杆菌H4处理后的再生细骨料(粒径≤5 mm)、粗骨料(粒径5~10 mm)、粗骨料(粒径10~20 mm)的吸水率分别降低2%、1.66%、0.69%;假坚强芽孢杆菌Bacillus pseudofirmus DSM8715处理的再生细骨料(粒径≤5 mm)、粗骨料(粒径5~10 mm)、粗骨料(粒径10~20 mm)的吸水率分别降低1.65%、1.37%、0.61%。

With the strengthening of the concept of green environmental protection,the technology of microbial mineralization and deposition modification of recycled aggregates has attracted more and more attention from domestic and foreign scholars.It mainly studies the self mineralization effect of Bacillus pseudofirmus DSM8715 and the H4 of Bacillus subtilis and the modification ability of regenerated aggregates.The micro-topography of microbial mineralized products was observed by SEM,the qualitative analysis of mineralized products was made by X-ray diffraction(XRD)technique,and the content of calcium carbonate in mineralized products was analyzed by Thermogravimetric Analyzer(TGA).The results showed that two kinds of microbial mineralization products were calcite-type calcium carbonate crystals,the content of calcium carbonate in the H4 mineralized products of the Bacillus was 94.32%,and the mineralization coefficient was 79.97%.And the false strong Bacillus pseudofirmus the content of calcium carbonate in DSM8715 mineralized products is only 86%,and mineralization coefficient is 68.4%.Compared with regenerated aggregate treated with microbial mineralization,the water absorption rate of H4 treated with Bacillus subtilis(≤5 mm),coarse aggregate(particle size 5~10 mm)and coarse aggregate(particle size 10~20 mm)decreased by 2%,1.66%and 0.69%respectively.The water absorption rate of the regenerated fine aggregate(particle size≤5 mm),coarse aggregate(particle size 5~10 mm)and coarse aggregate(10~20 mm)of Bacillus pseudofirmus DSM8715 treated by Bacillus subtilis was reduced by 1.65%,1.37%and 0.61%respectively.