Physical and mechanical properties and microscopic mechanisms of MgO-GGBS carbonated silty clay improved by sisal fiber
In order to solve the problems of high energy consumption and severe environmental pollution of traditional curing agents such as Portland cement,reactive magnesia(MgO)-granulated blast furnace slag(GGBS)was used to carbonize and improve silty clay,and sisal fibers were added to improve the cracking resistance of carbonated/solidified soil.The effects of fiber content and fiber length on the physical and mechanical properties of carbonated/solidified soil were studied.The results showed that,under the same fiber length,with the increase of fiber content,the volume growth rate,water content,and internal friction angle of MgO-GGBS carbonated/solidified soil samples increased.However,the cohesion first increased and then decreased.The unconfined compressive strength first increased and then decreased and finally tended to be stable,and the peak values of cohesion and unconfined compressive strength appeared when the fiber content was 0.4％.Under the same fiber content,with the increase of fiber length,the volume growth rate of MgO-GGBS carbonated/solidified soil samples first decreased and then increased,finally reaching the minimum as the fiber length was 10 mm.The moisture content remained almost constant.The unconfined compressive strength first increased and then tended to be stable,finally achieving the maximum when the fiber length was 5-10 mm.The failure strain increased with the increase of fiber length,but it was almost not affected by the fiber content.The cohesion and internal friction angle of carbonated fiber-containing soil samples first increased and then decreased finally reaching the maximum when the fiber length was 10 mm.Based on the results,a conceptual diagram of the reinforcement mechanism of MgO-GGBS carbonated soil improved by sisal fiber was proposed,and the improvement mechanism of carbonated soil based on the interweaving,fixing,and filling effects of fiber was revealed.The use of low-carbon materials such as MgO-GGBS-sisal fiber instead of Portland cement can significantly improve the treatment effect and crack resistance of carbonated silty clay.The research results would provide the theoretical guidance for promoting the application of the industrial solid waste GGBS and agricultural waste fiber in the field of soft foundation reinforcement and were of great significance for achieving the double-carbon goal of geotechnical engineering.
万方数据
维普
