Ebailila Mansour, Kinuthia John, Oti Jonathan
Department of Civil Engineering, Faculty of Engineering, Bani Waleed University, Bani Waleed, Libya.
School of Engineering, Faculty of Computing, Engineering and Science, University of South Wales, Pontypridd CF37 1DL, UK.
Materials (Basel). 2022 Apr 12;15(8):2821. doi: 10.3390/ma15082821.
Sulfate-induced expansion resulting from the formation of ettringite in sulfate-bearing soil stabilised with calcium-based stabilisers is a problematic issue with technical and economic implications. Thus, this research examines the viability of the co-addition of lime (L) and silica fume (S) at varying binder dosages (4, 6, and 10 wt%), with a view of establishing the optimum blend of L-S for suppressing the ettringite-induced expansion of artificially high sulfate-dosed soil (kaolinite-K and gypsum-G). To do so, a series of laboratory specimens, designed using different gypsum and lime concentrations, were investigated using unconfined compression strength (UCS), linear expansion, and derivative thermo-gravimetric analysis (DTG) as the main criteria for the examination. The research outcomes indicated that the increasing substitution of L with S induces a gradual reduction on the UCS and linear expansion at binder levels of 4 and 6 wt%, while its usage in a high binder level (10 wt%), can yield an expansion reduction, with no compromise on the UCS performance. Therefore, silica fume has the potential for restricting ettringite formation and suppressing the expansion, of which 3L7S is the optimum blending ratio for suppressing the expansion.
在含钙稳定剂稳定的含硫酸盐土壤中，由于钙矾石的形成而导致的硫酸盐诱导膨胀是一个存在技术和经济影响的问题。因此，本研究考察了在不同粘结剂剂量（4%、6%和10%重量）下同时添加石灰（L）和硅灰（S）的可行性，目的是确定L-S的最佳混合比例，以抑制人工高硫酸盐剂量土壤（高岭土-K和石膏-G）中钙矾石诱导的膨胀。为此，使用不同石膏和石灰浓度设计了一系列实验室试样，以无侧限抗压强度（UCS）、线性膨胀和导数热重分析（DTG）作为主要检测标准进行研究。研究结果表明，在粘结剂含量为4%和6%重量时，用S逐渐替代L会使UCS和线性膨胀逐渐降低，而在高粘结剂含量（10%重量）下使用S，可减少膨胀，且不影响UCS性能。因此，硅灰有潜力限制钙矾石的形成并抑制膨胀，其中3L7S是抑制膨胀的最佳混合比例。
