凹凸棒石黏土对水泥稳定碎石性能的影响
Influence of palygorskite clay on properties of cement-stabilized macadam

为了避免水泥稳定碎石基层收缩开裂的产生、延长路面使用寿命,在水泥稳定碎石基层中掺加凹凸棒石黏土来改善其力学性能与抗裂性能.试验结果表明,与空白试样相比,在各自最佳掺量下,掺X型凹凸棒石黏土、Y型凹凸棒石黏土和Y型煅烧凹凸棒石黏土的水泥稳定碎石的7 d无侧限抗压强度分别提高约5.9%,5.4%和21.5%,50 d后其干缩系数较空白试验分别减小约13.7%,7.4%和20.5%,且掺入凹凸棒石黏土后水泥稳定碎石的失水率也有一定程度的下降.采用扫描电镜观察水泥砂浆的微结构,发现凹凸棒石黏土掺入后生成较多的水化产物,形成网状结构,从而大大减少了水泥稳定碎石的收缩裂缝数量.
To avoid the occurrence of the shrinkage cracks of cement-stabilized macadam base and prolong the life span of pavement, palygorskite clay was mixed in cement-stabilized macadam base to improve the strength properties and crack resistance. The experimental results show that compared with the blank sample, the unconfined compressive strengths of the cement-stabilized macadam mixed by type X palygorskite clay, type Y palygorskite clay and type Y calcined palygorskite clay with the corresponding optimal contents increase by about 5.9%,5.4% and 21.5%,respectively, at the curing age of 7 d. And after 50 d, their dry-shrinkage coefficients reduce by about 13.7%, 7.4% and 20.5%, respectively. Meanwhile, the water loss rate of the cement-stabilized macadam mixed with palygorskite clay also decreases to a certain extent. The microstructure of the cement pastes mixed with palygorskite clay is observed by scanning electronic microscope. The results show that more fibrous hydration products and a net-like microstructure exist in the cement pastes mixed with palygorskite clay, inducing the great decrease of the number of the shrinkage cracks of the cement-stabilized macadam