旧料掺量对乳化沥青冷再生混合料路用性能的影响

摘要

为得到乳化沥青冷再生混合料中旧料的最佳掺量,现通过室内试验研究乳化沥青混合料中旧料(RAP)掺量对其力学性能和路用性能的影响.结果表明:RAP掺量为45％时的无侧限抗压强度最大值3.22 MPa;劈裂强度达到最大值0.66 MPa;混合料的高温稳定性及低温抗裂性会随着RAP的增多而降低,当RAP掺量为45％时混合料的动稳定度和弯曲应变最大,分别为3 792次/mm、2 914με;随着RAP掺量增大,混合料的水稳定性逐渐降低,当RAP掺量为75％时,其残留稳定度为78.75％,低于规范值;混合料的抗疲劳性随RAP掺量增加呈现先增大后减小的趋势,当RAP掺量为55％时,混合料的抗疲劳性最好,应力比为0.7时疲劳寿命值达到18 608次.通过工程实例分析得出,RAP掺量为45％时,其弯沉值、压实度、抗压强度与劈裂强度均满足要求,并总结出施工质量控制措施.%In order to obtain the best mixing amount of old materials in cold recycled mixture of emulsified asphalt,through the laboratory experiments,this paper studied the old material content of the emulsified asphalt mixture on the mechanical properties and the road performance.The results show that the unconfined compressive strength with the RAP content 45 ％ is the largest 3.22 MPa,and the splitting strength reaches the maximum 0.66 MPa.The high temperature stability and low temperature crack resistance of the mixture decreases with the increasing RAP content.When the content of RAP is 45％,the dynamic stability and bending strain run up to the largest,respectively 3792 times min and 2914 με.With the increase of RAP content,the water stability of mixture reduce gradually.When the RAP content is 75 ％,the residual stability is 78.75 ％ which is lower than the standard value.With the increases of RAP content the anti fatigue performance of the mixture showed a decreasing trend after the increase at early stage.When the content of RAP is 55％ the fatigue resistance of the mixture is the best,and the fatigue life is up to 18608 times with the stress ratio 0.7.Taking a practical project as an example,when the RAP content is 45 ％,the deflection value,the compaction degree and the compressive strength and the splitting strength can meet the requirements well.Finally this paper summarized the construction quality control measures.