二次冷再生可行性分析及其混合料力学性能试验研究

Feasibility Analysis and Experimental Study on Mechanical Properties of Secondary Cold Regeneration Mixture

目前国内部分冷再生路面达到或接近使用寿命,旧冷再生路面能否进行二次再生利用成为公路行业的关注热点。首先对二次冷再生进行可行性分析,并基于二次冷再生混合料的配合比设计结果,对二次冷再生混合料的力学性能进行试验研究。结果表明:旧冷再生路面的基层材料压碎值仍满足规范要求,但CBR值发生了衰减,级配呈细化状态,单独用于二次再生修筑路面(底)基层已不可行;通过添加新骨料及水泥稳定剂,二次冷再生混合料的级配和强度得到有效改善,7 d无侧限抗压强度值可满足极重、特重交通下的路面(底)基层技术要求,二次冷再生具备可行性;二次冷再生混合料的力学性能试验结果虽略次于初次再生混合料的性能,但整体力学性能仍能满足沥青路面基层及底基层的力学指标要求。

At present,part of the cold recycled pavement in China has reached or is close to its service life.Whether the old cold recycled pavement can be recycled has become the focus of the highway industry.In this paper,the feasibility of secondary cold regeneration is analyzed firstly.Based on the mix design results of secondary cold regeneration mixture,the mechanical properties of secondary cold regeneration mixture are tested and studied.The results show that the crushing value of the old cold recycled pavement base material still meets the specification requirements,the CBR value is attenuated,and the grading is refined,so it is not feasible to use it alone for the secondary recycled pavement(subbase)base;By adding new aggregate and cement stabilizer,the gradation and strength of the secondary cold recycled mixture have been effectively improved.The 7 d unconfined compressive strength value can meet the technical requirements of the pavement(subbase)under heavy and extremely heavy traffic.The secondary cold recycling is feasible.Although the mechanical performance test results are slightly inferior to that of the primary recycled mixture,the overall mechanical performance can still meet the mechanical index requirements of the asphalt pavement base and subbase.