水泥稳定再生沥青路面/红土混合物用于软土改良的效果评估

Evaluation of cement stabilized recycled asphalt pavement/lateritic soil blends for soft soil improvement

评估了水泥稳定再生沥青路面(RAP)/边缘红土混合物作为碎石桩骨料替代传统采石场骨料的潜力,研究了混合材料在不同RAP置换率和有效约束压力下的不排水剪切强度变化。RAP置换率分别为10%、30%和50%(按干重计),普通硅酸盐水泥含量分别为1%和3%。很明显,RAP的置换增加了大颗粒,同时减少了细小颗粒,因此增加了压实度。在低于先期固结压力的有效应力下,RAP-土颗粒混合物表现出与孔隙压力降低相关的应变硬化性能。当RAP置换率增加时,水泥稳定的RAP-土颗粒混合物应力-应变曲线的应变软化性能减弱。胶结作用提高了黏聚力,而内摩擦角未产生明显的变化。水泥稳定的RAP-土颗粒混合物的强度和刚度主要取决于胶结强度和RAP置换率。抗剪强度随着非稳定和水泥稳定的RAP-土颗粒混合物的RAP置换率增加而提高,而水泥稳定的RAP-土颗粒混合物的刚度由于沥青黏结剂的高能量吸收而下降。

This research evaluates the potential of cement stabilized recycled asphalt pavement(RAP)/marginal lateritic soil blends as stone column aggregate instead of the traditional quarry aggregate. The undrained shear response of the blended materials at various RAP replacement ratios and effective confining pressures are investigated. The RAP replacement ratios were 10%, 30% and 50% by dry weight and ordinary Portland cement contents were 1% and 3%. It was evident that RAP replacement increased large particles and meanwhile reduced fines particles;hence the increased compactibility. Under applied effective stress lower than pre-consolidation pressure, RAP-soil blends exhibited strain-hardening behavior associated with decreased pore pressure. The strain-softening behavior in stress-strain curve for cement stabilized RAP-soil blends was diminished when RAP replacement ratio increased. The role of cementation improved the cohesion while friction angle insignificantly unchanged. The strength and stiffness of cement stabilized RAP-soil blends is mainly dependent upon the cementation bond strength and RAP replacement ratio. Shear strength improvement increased with the increased RAP replacement ratio for both unstabilized and cement stabilized RAP-soil blends, while stiffness of cement stabilized RAP-soil blends decreased due to high energy absorption of asphalt binder.