活性MgO碳化固化土的冻融循环特性试验研究

发布时间：2018-08-10 18:35

【摘要】：采用室内三轴碳化装置研究了活性Mg O碳化固化土的冻融耐久性能,对冻融循环作用下碳化固化土的无侧限抗压强度等进行了测试分析,并与水泥固化土进行了试验比较.结果表明:活性Mg O固化粉土碳化3 h试样的无侧限抗压强度可达5 MPa左右,粉质黏土碳化24 h试样可达4.5 MPa左右;冻融循环作用下,碳化试样和水泥土试样的密度和干密度基本不变;碳化试样与水泥土试样在冻融循环中的无侧限抗压强度和E50表现出类似的变化趋势,即先略有降低,后又逐渐提高.碳化固化土经6次冻融循环后,其强度由5 MPa左右降低到4.5 MPa左右,而水泥土试样经4次冻融循环后其强度由1.6 MPa降低到1.4 MPa左右,二者均具有较好的抗冻融性能.微观测试分析表明,活性Mg O碳化固化土生成的镁碳酸化合物经冻融循环后没有发生明显变化,但试样内部0.1~1.0μm的孔隙减少,1~30μm的孔隙增加,累计孔隙体积略有增加,这也是导致强度略有降低的原因.
[Abstract]:The freeze-thaw durability of activated Mg O carbonized solidified soil was studied by triaxial carbonation in laboratory. The unconfined compressive strength of carbonized solidified soil under freeze-thaw cycling was tested and analyzed. The results showed that the unconfined compressive strength of activated Mg O-solidified silt carbonized for 3 h could reach 5. The density and dry density of carbonated and cement-soil samples are almost unchanged under freeze-thaw cycles, and the unconfined compressive strength and E50 of carbonated and cement-soil samples show a similar trend in freeze-thaw cycles, i.e. slightly decreased at first and then gradually increased. After six freeze-thaw cycles, the strength of solidified soil decreases from about 5 MPa to about 4.5 MPa, while that of cement soil decreases from 1.6 MPa to about 1.4 MPa after four freeze-thaw cycles. Both of them have good freeze-thaw resistance. Microscopic test analysis shows that magnesium carbonate formed by activated Mg O carbonate solidified soil is lost after freeze-thaw cycles. There are obvious changes, but the porosity of 0.1-1.0 micron decreases, the porosity of 1-30 micron increases, and the cumulative pore volume increases slightly, which is also the reason for the slight decrease of strength.
【作者单位】：东南大学岩土工程研究所;东南大学江苏省城市地下工程与环境安全重点实验室;
【基金】：国家自然科学基金资助项目(51279032) “十二五”国家科技支撑计划资助项目(2012BAJ01B02) 中央高校基本科研业务费专项资金资助项目江苏省普通高校研究生科研创新计划资助项目(KYLX_0147)
【分类号】：TU411

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