级配和水泥掺量对泡沫沥青冷再生混合料路用性能的影响

为评价级配和水泥掺量的影响,分别采用无侧限抗压强度试验、浸水马歇尔试验、冻融劈裂试验、车辙试验和小梁弯曲试验对不同类型泡沫沥青冷再生混合料的力学性能、水稳定性、高温稳定性和低温抗裂性进行测试。研究结果表明:在再生料中掺加新集料可以降低2.3%~3.3%的空隙率。通过同时掺加新粗、细集料和矿粉来进行再生料级配优化可以获得最优的力学性能和高温稳定性,但是其水稳定性和低温抗裂性不如仅掺加新细集料和矿粉的情况。虽然再生料路用性能随着水泥掺量的增加而不断提高,但是考虑到潜在的收缩开裂问题,建议在控制水泥掺量的前提下通过优化级配来改善泡沫沥青冷再生混合料的路用性能。级配和水泥掺量对于不同的路用性能的影响显著性有所差异。级配对高温稳定性的影响更加显著,而水泥剂量对水稳定性的影响更加显著。

Effects of aggregate gradations and cement content on pavement performance of cold recycled mixture with foamed asphalt

The unconfined compressive test,immersion Marshall test,freeze-thaw splitting test,wheel tracking test,and beam bending test were conducted on different types of cold recycled mixtures with foamed asphalt to measure the mechanical strength,moisture stability,high-temperature performance,and low-temperature performance,respectively.The effects of aggregate gradations and cement content were evaluated.It is found that adding new aggregates in recycled mixtures reduces the air void by 2.3%~3.3%.The best mechanical and high-temperature performance can be achieved by adding new coarse and fine aggregates as well as fillers to optimize the gradation.However,its moisture stability and low-temperature performance are poorer than those by only adding fine aggregates and fillers.Although the performance of recycled mixtures is enhanced constantly with the increase of the cement content,it is recommended that the performance of cold recycled mixtures with foamed asphalt should be improved by the gradation optimization based on the limitation of the cement content in consideration of the potential shrinkage cracking problem.The effect significance of aggregate gradations and cement content varies with the pavement performance.Aggregate gradations show a more significant effect on the high-temperature performance whereas the cement content has a more significant effect on the moisture stability.