橡胶水泥稳定碎石混合料抗裂性能研究

Research on Cracking Resistance of Rubber Cement Stabilized Gravel Mixture

由于水泥稳定碎石基层具有整体强度较高、抗渗性和水稳性好、原材料来源广、成本低等优点,成为我国最为常见的路面基层形式。但由于水泥稳定碎石基层开裂造成的反射裂缝问题一直未得到有效解决,水泥稳定碎石基层的干缩裂缝问题成为制约道路使用寿命的最主要因素。文章通过在水泥胶砂中添加0、1%、2%和3%的橡胶粉,分析了水泥胶砂抗折和抗压性能的变化情况;在水泥稳定碎石混合料中添加0、1%、2%和3%的橡胶粉,进行了无侧限抗压强度和干缩性能试验。结果表明:随着橡胶粉掺量的增多,水泥胶砂强度呈先增大后减小趋势,在橡胶粉掺量为1%时强度最高;水泥稳定碎石混合料无侧限抗压强度则呈下降趋势,同时干缩系数也会减小,说明橡胶粉在降低水泥稳定碎石混合料强度的同时也会改善其干缩性能。因此,结合橡胶粉对水泥稳定碎石混合料干缩性能和无侧限抗压强度的影响,可以通过掺加橡胶粉的方式改善水泥稳定碎石基层的开裂问题,但橡胶粉宜采用低掺量,建议掺量为1%左右,具体的掺量还需要根据现场试验确定。

Cement stabilized gravel base has the advantages of high overall strength,good impermeability and water stability,wide sources of raw materials and low cost,and has become the most common pavement base form in our country.The problem of reflection crack caused by cement stabilized gravel base cracking has not been solved effectively.The dry shrinkage crack of cement stabilized gravel base has become the main factor restricting the service life of road.By adding 0,1%,2%and 3%rubber powder to the cement mortar,the change of the bending and compressive properties of the cement mortar is analyzed.The results show that the strength of the cement mortar increases first and then decreases with the reinforcement degree of the rubber powder dosage,and the strength is the highest when the rubber powder dosage is 1%.By adding 0,1%,2%and 3%rubber powder to cement stabilized gravel mixture,the unconfined compressive strength and dry shrinkage performance of cement stabilized gravel mixture is tested.The results show that with the addition of rubber powder,the unconfined compressive strength of cement stabilized gravel mixture shows a downward trend,and the dry shrinkage coefficient will also decrease,indicating that rubber powder will reduce the strength of cement stabilized gravel mixture and improve its dry shrinkage performance.Therefore,combined the influence of rubber powder on the dry shrinkage performance and unconfined compressive strength of the cement stabilized gravel mixture,the crack resistance of cement stabilized gravel base can be improved by adding rubber powder.However,the rubber powder should be mixed with a low content,and the recommended content is 1%.The specific dosage of rubber powder needs to be determined according to the field test.