Knight J, Cheeseman C, Rogers R
Department of Civil and Environmental Engineering, Imperial College of Science Technology and Medicine, London, UK.
Waste Manag. 2002;22(2):187-93. doi: 10.1016/s0956-053x(01)00068-x.
Ordinary cement pastes with water/cement (w/c) ratios of 0.2, 0.4 and 0.5 were used to examine the chemical and physical effects of microbial influenced degradation (MID). Samples were exposed to an active culture of Thiobacillus thiooxidans or to sterile media containing sulphuric acid using an intermittent immersion technique. Acid consumption and Ca, Al and Fe releases are presented for an exposure period of 90 days. Exposed samples were also sectioned and analysed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). All cement paste samples were subject to significant degradation in either sterile acid media or the T. thiooxidans lixiviant. Corrosion depths observed from SEM examination of exposed samples were affected by the w/c ratio of the cement. The extent and rate of degradation were not apparent from the calculated rate of hydrogen ion consumption, or the leaching rates of Ca, Al and Fe. It was not possible to distinguish differences in corrosion due to the chemical and microbial influenced degradation from the results obtained to date and further work is focusing on modified procedures to address this.
使用水灰比（w/c）分别为0.2、0.4和0.5的普通水泥浆体来研究微生物影响的降解（MID）的化学和物理效应。采用间歇浸泡技术，将样品暴露于氧化硫硫杆菌的活性培养物中，或含有硫酸的无菌培养基中。给出了90天暴露期内的酸消耗量以及钙、铝和铁的释放量。还对暴露后的样品进行切片，并通过扫描电子显微镜（SEM）和能量色散X射线（EDX）进行分析。所有水泥浆体样品在无菌酸性介质或氧化硫硫杆菌浸出液中均遭受了显著降解。从暴露样品的SEM检查中观察到的腐蚀深度受水泥水灰比的影响。从计算出的氢离子消耗速率或钙、铝和铁的浸出率来看，降解的程度和速率并不明显。从目前获得的结果中，无法区分化学和微生物影响的降解所导致的腐蚀差异，进一步的工作正集中在改进程序以解决这一问题上。
