Abstract: The disadvantages of cement stabilized macadam, such as drying shrinkage and thermal shrinkage, often cause the cracking of roads. Addition of waste tire rubber particles into cement stabilized macadam can not only achieve resource recycling but also improve the shrinkage cracking characteristics of cement stabilized macadam by utilizing the high elasticity of rubber. Due to the significant modulus difference between rubber and cement stone, the interface transition zone between the two is weak, which reduces the mechanical properties of the material. Therefore, NaOH was used for surface modification treatment of rubber. At the same time, dry shrinkage test, thermal shrinkage test and strength test were conducted to explore the influence of the modified rubber on the shrinkage cracking and mechanical performance of cement stabilized macadam. Scanning electron microscopy and energy spectrometer were used to analyze the morphology and chemical composition of interface. The results show that the thermal shrinkage and dry shrinkage of cement stabilized macadam with modified rubber powder were further reduced compared to cement stabilized macadam with untreated rubber, while the unconfined compressive strength is increased by more than 5%. The crack gap between the surface treated rubber and cement stone is significantly improved, and the value of Ca/Si in the interface transition zone is decreased. The generation of C—S—H in the interface transition zone is increased, the rubber particles are tightly wrapped by cement stone and the interface is tightly bonded. The above results indicate that the addition of surface-modified rubber powder in the cement stabilized macadam effectively improves its shrinkage cracking performance and strength characteristics.

Key words: highway engineering; rubber; surface treatment; cement stabilized macadam; dry shrinkage; thermal shrinkage

摘要： 水泥稳定碎石易干缩、温缩等缺点常诱发并导致路面裂缝的产生，将废旧轮胎橡胶颗粒掺入水稳碎石中不仅可以实现资源的循环利用，还可利用橡胶的高弹性改善水稳碎石的缩裂特性。由于橡胶与水泥石之间存在巨大模量差异，二者的界面过渡区薄弱，降低了材料力学性能。为此，采用NaOH对橡胶进行表面改性处理，进行干缩、温缩和强度试验探究改性橡胶对水稳碎石缩裂和力学性能的影响，采用扫描电镜和能谱仪分析界面形态及化学组成。结果显示：加入改性橡胶粉的水稳碎石温缩和干缩均比掺加未改性橡胶颗粒进一步降低，而无侧限抗压强度则提高5%以上；表面处理橡胶与水泥石之间的裂缝间隙得到了明显改善，界面过渡区Ca/Si值下降、C—S—H生成量增加，橡胶颗粒被水泥石紧密包裹、界面结合紧密。结果表明：将橡胶粉表面改性后掺入水泥稳定碎石有效提高了其缩裂性能和强度特性。

关键词: 道路工程 ；橡胶；表面处理；水泥稳定碎石；干缩；温缩