全深式水泥稳定就地冷再生基层应用与耐久性能评价

为了将含有回收沥青路面材料及回收基层材料的废旧路面材料就地水泥冷再生后用于高速公路的基层,并能在短期内快速评价水泥就地冷再生基层的耐久性能,大广高速奈曼东连接线进行了全深式水泥稳定就地冷再生基层和骨架密实型水泥稳定碎石基层的劈裂强度、无侧限抗压强度、弯拉强度、动态压缩模量试验(中间段法)、干缩温缩应变、冻融循环水稳定性与抗疲劳耐久性等的对比研究,进而采用足尺加速加载试验评价了全深式水泥稳定就地冷再生基层的长期使用性能。研究结果表明,全深式水泥稳定就地冷再生混合料的7d无侧限抗压强度、弯拉强度、动态压缩模量完全能满足规范中高速公路基层的要求;相同试验条件下,水泥稳定就地冷再生混合料的强度特性、力学性能、抗冻性及疲劳寿命均小于新成型骨架密实型水泥稳定碎石混合料,但2种半刚性基层的承载能力相差不大;在持续荷载作用下,路面基层疲劳损伤累积会导致其承载能力不断衰减,随着试验轮加载次数增大,2种半刚性基层弯沉代表值持续增大,而弯沉增长率呈先显著增大后趋于平稳的变化趋势,全深式水泥稳定就地冷再生基层的承载能力衰减对重复荷载作用更加敏感。足尺加速加载试验加载了120万次后,全深式水泥稳定就地冷再生基层未发生疲劳开裂病害,也表现出了良好的耐久性能;建议改扩建工程中,宜将全深式水泥稳定就地冷再生基层应用于交通量较小的车道方向。

Application and Durability Evaluation of Full-deep Cement Stabilized In-situ Cold Recycled Mixture Base

In order to reclaim the waste concrete material containing recycled asphalt pavement material and recycled base material for the base layer of the expressway,and to quickly evaluate the durability of the cold recycled base layer in the short-term,the Daguang Expressway was carried out.Nyman East Connection Line Full-deep Cement Stabilized In-situ cold recycled base and Skeleton-Dense Cement Stabilized Macadam Base Layer Splitting Strength,Unconfined Compressive Strength,Tensile Strength,dynamic compression modulus test(Intermediate Section Method)The comparative study of dry shrinkage and shrinkage strain,freeze-thaw cycle water stability and fatigue durability,and then the full-scale accelerated performance of the full-deep cement stabilized in-situ cold regenerated base layer was evaluated by full-scale accelerated loading test.The results show that the 7d unconfined compressive strength,bending strength and dynamic compressive modulus of the full-deep cement stabilized in-situ cold recycled mixture can fully meet the requirements of the highway base layer in the specification;under the same test conditions,the cement is stable.The strength characteristics,mechanical properties,frost resistance and fatigue life of the in-situ cold recycled mixture are smaller than the newly formed skeleton compact cement stabilized macadam mixture,but the bearing capacity of the two semi-rigid base layers is not much different;Under the fatigue damage accumulation of the pavement base layer will lead to the continuous decline of its bearing capacity.As the number of test wheel loading increases,the representative values of the two semi-rigid base layers continue to increase,while the growth rate of the deflection increases significantly.A steady trend of change,the full-deep cement stabilized in-situ cold-recycled base layer with reduced bearing capacity is more sensitive to repeated loads.After the full-scale accelerated loading test was loaded 1.2 million times,the full-deep cement stabilized on-site cold regenerated base layer did not have fatigue cracking disease,and also showed good durability;it is recommended to stabilize the full-deep cement in the expansion and reconstruction project.The in-situ cold reclaimed base layer is applied to the direction of the lane with less traffic.