防膨型土壤固化剂制备及固化机理研究

Preparation and curing mechanism of anti-swelling soil stabilizer

为了确定防膨型土壤固化剂的最佳配合比,以固化土自由膨胀率为指标,最终确定防膨型固化剂的配合比为m(水性环氧树脂)∶m(碱激发剂)∶m(稳定剂)∶m(偶联剂)∶m(分散剂)∶m(氯化物)∶m(水)=25∶20∶1.5∶0.3∶0.3∶0.04∶52.86,此时固化土的自由膨胀率最小,为11%。XRD和SEM分析可知,固化机理主要有水泥水化水解反应,碱激发剂与水泥水化产物反应增强作用,稳定剂抑制膨胀土的水化膨胀、分散运移,水性环氧-偶联剂复合物水解聚合反应胶结、增强作用,氯化物抑制土的水化膨胀。路基试验段测试结果表明,养护7 d后路基固化土压实度可达92%~96%,弯沉平均值为104.5 mm,无侧限抗压强度为2.26 MPa,水稳定系数为84.1%。

In order to determine the best mix ratio of anti-swelling soil stabilizer,by testing solidified soil free expansion rate,finally selected formula for mass fraction ratio of new curing agent for waterborne epoxy resin∶alkali excitation agent∶stabilizing agent∶coupling agent∶dispersant∶chloride∶water=25∶20∶1.5∶0.3∶0.3∶0.04∶52.86,at this time the minimum free expansion rate of solidified soil mixed with anti-swelling soil stabilizer is 11%.X-ray diffraction(XRD)and scanning electron microscope of solidified soil show that the curing mechanism is mainly cement hydration hydrolysis reaction,alkaline exciting agent and cement hydration reaction product enhancement,hydration swelling and dispersion of migration of stabilizer inhibitory expansive soil,waterborne epoxy-coupling agent compound hydrolysis polymerization cementation,enhancing effect,hydration expansion effect of chloride inhibiting soil.The results of subgrade test section show that after curing for 7 days,the compaction of the roadbed solidified soil can reach 92%~96%,the average value of bending and settling is 104.5 mm,the unconfined compressive strength is 2.26 MPa,and the water stability coefficient is 84.1%.