考虑剪切性能的泡沫沥青混合料配合比设计

Optimization of mixture ratio design with foamed bitumen considering anti-shear performance

在传统泡沫沥青冷再生混合料配合比设计的基础上,基于摩尔–库伦强度理论,提出考虑抗拉、抗水损和抗剪切性能的泡沫沥青用量综合指标,优化了泡沫沥青冷再生混合料配合比设计方法。同时为解决车辙试验试件成型复杂、耗材多、耗时长等缺陷,提出基于标准马歇尔试件的单轴贯入试验对混合料高温抗剪切性能进行评价,为设计和检验高抗剪泡沫沥青冷再生混合料开展系统研究。结果表明:以综合指标优化配合比设计,泡沫沥青用量降低,在保证混合料抗水损性能的基础上,有效提高混合料高温抗剪切性能;基于标准马歇尔试件的单轴贯入试验,可有效评价混合料高温抗剪切性能,贯入速率1 mm/min、试验温度60℃为最佳试验条件;最大贯入荷载与动稳定度存在较好的线性相关,以动稳定度规范限值推算出贯入荷载限值,为该评价方法的应用提供限值参考。

On the basis of the existing design method for the cold recycling mixture with foamed bitumen,the comprehensive index considering the tensile performance,water stability and shear resistance was put forward to optimize the mixture ratio design.At the same time,in order to solve the defects of rut test specimen,such as complex forming,more consumables and time consuming,a uniaxial penetration test based on standard Marshall test specimen was proposed to evaluate the shear resistance of the mixture.In order to design a mixture for heavy duty highway,a systematic study was carried out.The results show that the dosage of foamed bitumen can be reduced by optimizing the mixture ratio design with comprehensive index.On the basis of ensuring the water stability of the mixture,the high temperature shear resistance of the mixture is effectively improved.The uniaxial penetration test based on the standard Marshall specimen can be used to effectively evaluate the high temperature shear resistance of the mixture.The optimum experimental conditions include penetration rate of 1 mm/min and test temperature of 60℃.There is a good linear correlation between the maximum penetration load and the dynamic stability.Based on the limit value of the dynamic stability,the penetration load limit value satisfying the road performance requirements is calculated.This provides a reference for the application of the evaluation method.