泡沫沥青冷再生混合料力学特性试验

Test of Mechanical Property of Cold Recycled Mixture with Foamed Bitumen

采用间接拉伸强度、无侧限抗压强度及抗压回弹模量试验,分析了沥青路面旧料掺量及水泥用量对泡沫沥青冷再生混合料力学特性的影响。研究表明:随旧料掺量的增大或其中旧沥青含量的增多,泡沫沥青冷再生混合料设计最佳沥青用量减少,冷再生混合料抗拉、抗压、抗剪性能呈下降趋势,而抗压回弹模量逐渐增大;水泥用量的增大有助于提高冷再生混合料的强度、刚度及其水稳定性,但用量过大不利于冷再生混合料的抗裂性能,建议不超过2%;水泥用量较小(≤1.5%)的冷再生混合料强度增长主要集中于室温养生的24 h以及40℃烘箱养生的第1个24 h内,而水泥用量较大(1.5%～3%)的冷再生混合料养生期内强度增长比较匀速。

By indirect tensile strength test, unconfined compressive strength test and compressive resilient modulus test, the influences of recycled asphalt pavement （RAP） content and cement content on mechanical property of cold recycled mixture with foamed bitumen （CRMFB） were studied. The results indicate that （ 1 ） Increase of RAP content or content of old bitumen in RAP led to decrease of optimum foamed asphalt content and tensile, compressive, and shear strengths, but increase of compressive resilient modulus for CRMFB. （2） Increase of cement content contributed to the enhancement of mechanical property and water susceptibility of CRMFB. However, an excess of cement would have negative effect on crack resistance of CRMFB, so the cement content is suggested to be limited to 2% or less. （3） For the CRMFB with lower cement content （ ≤1.5% ）, the strength increase mainly concentrated in the period of the 24 h at open air curing and the first 24 h at 40℃ oven curing, while for the CRMFB with higher cement content （1.5% - 3 % ）, an uniform strength increase appeared in the whole curing period.