含高吸水树脂的自养护水泥稳定基层的收缩特性

Shrinkage characteristics of self-curing cement stabilized macadam base with super absorbent polymer

为提高水泥稳定碎石基层的抗裂能力,选择聚丙烯酸高吸水树脂(SAP)材料作为自养护剂添加到基层混合料中,通过振动压实试验、无侧限压缩强度试验、干缩特性试验和温缩特性试验对其力学性能和收缩特性进行研究。结果表明:SAP的掺入可显著提高水泥的水化程度,大幅抑制水泥稳定碎石基层的收缩应变,改善其内部结构。养护时间达到28 d时,掺入SAP的水泥稳定碎石基层的累计干缩应变降低了32.9%,干缩系数降低了33.8%,累计温缩应变降低了14.1%,平均温缩系数降低了15%。此外,还构建了水泥稳定碎石基层干缩系数与时间区间、温缩系数与温度区间的关系模型,为后续SAP自养护水泥稳定碎石基层的研究与应用提供理论及技术依据。

In order to improve the crack resistance of cement stabilized macadam base, the polyacrylic acid super absorbent polymer( SAP) material was selected as a self-curing agent to be added into the base mixture. The mechanical properties and shrinkage characteristics of the materials were studied through vibration compaction test, unconfined compressive strength test, dry-shrinkage test and temperature-shrinkage test. The results showed that the addition of SAP could significantly improve the hydration degree of cement,greatly inhibit the shrinkage strain of cement-stabilized macadam base and improve its internal structure. When the curing time reached28 d, the accumulated dry shrinkage strain, dry shrinkage coefficient, accumulated temperature shrinkage strain and average temperature shrinkage coefficient of the cement stabilized macadam base mixed with SAP were reduced by 32.9%, 33.8%, 14.1% and 15%,respectively. In addition, the relationship models between the dry shrinkage coefficient and time interval, and the temperature shrinkage coefficient and temperature interval of cement-stabilized macadam base were also constructed to provide theoretical and technical basis for the subsequent research and application of SAP self-curing cement-stabilized macadam base.