DWMAS型温拌剂对碎石封层橡胶沥青表观黏度及路用性能的影响

Effect of DWMA-S Warm Agent on Performance Properties and Apparent Viscosity of Asphalt Rubber for Chip Seals

采用针入度、软化点、弹性恢复率、测力延度、180℃布氏旋转黏度试验表征了DWMA-S型温拌剂对碎石封层橡胶沥青结合料高温路用性能、低温韧性,以及表观黏度的影响.结果表明:①掺加温拌剂后橡胶沥青25℃针入度增大,软化点略有降低,25℃弹性恢复率及低温延度变化不显著,说明该复合型温拌剂对橡胶沥青针入度和软化点的影响规律与稀释类温拌剂类似,且可能会对橡胶沥青低温变形能力产生一定负面影响;②橡胶沥青低温力-延度曲线具有硬而韧的特点,有明显的屈服和屈服软化现象;温度升高,橡胶沥青、温拌橡胶沥青的屈服力分别降低54.3%、57.5%,断裂力降低46.5%、48.3%,断裂能则降低25.56%、35.90%,说明温度升高,低温韧性显著降低.③掺加温拌剂后,橡胶沥青屈服力、断裂力、断裂能均降低,与升高温度对低温韧性的影响规律一致.④DWMA-S型温拌剂可降低橡胶沥青180℃表观黏度40%~50%,故采用温拌橡胶沥青作碎石封层胶结料,能显著降低洒布温度,降低施工阶段的CO_(2)排放量.

The effects of DWMA-S warm mix on high-temperature pavement performance,low-temperature toughness and apparent viscosity of rubber asphalt binder for crushed stone seal were characterized by penetration,softening point,elastic recovery rate,force ductility and Brinell rotational viscosity test at 180℃.The results show that:①The penetration of rubber asphalt at 25℃ is increased and the softening point is slightly decreased after adding heating admixture.The elastic recovery rate and low-temperature ductility at 25℃ have no significant change,which indicates that the influence of the compound warm-mix agent on the penetration and softening point of rubber asphalt is similar to that of the diluted warm-mix agent,and it may have some negative effects on the low-temperature deformation ability of rubber asphalt.②The low temperature force-ductility curve of rubber asphalt is hard and tough,with obvious yield and yield softening.With the increase of temperature,the yield force of rubber asphalt and warm mix rubber asphalt decreased by 54.3% and 57.5%,the breaking force decreased by 46.5% and 48.3%,and the breaking energy decreased by 25.56% and 35.90% respectively.It shows that the low-temperature toughness decreases significantly with the increase of temperature.③The yield force,breaking force and breaking energy of rubber asphalt decreased after adding heating admixture,which was consistent with the effect of increasing temperature on low-temperature toughness.④DWMA-S warm mixing agent can reduce the apparent viscosity of rubber asphalt at 180℃ by 40%~50%.Therefore,using warm-mixed rubber asphalt as the binder of crushed stone seal coat can significantly reduce the spreading temperature and the carbon dioxide emission in the construction stage.