应力吸收层热再生混合料力学性能与路用性能试验研究

RAP中细集料的老化沥青含量大，再生利用价值高，将RAP应用于应力吸收层混合料，可最大资源化提升RAP再生利用价值，降低应力吸收层混合料建设成本。采用车辙试验、小梁弯曲试验、预切缝半圆弯拉试验、复合梁试件扭剪试验、拉拔试验、扭剪疲劳试验、Over Test评价热再生应力吸收层混合料的高低温性能、层间抗剪切性能、抗剪切疲劳性能和抗反射裂缝性能。结果表明：随着RAP掺配比例增大，热再生应力吸收层混合料的油石比降低、高温性能增强，但增大RAP掺量导致热再生应力吸收层混合料低温弯曲应变、断裂能、扭剪强度、拉拔强度、扭剪疲劳寿命和抗反射裂缝性能均降低。在50%RAP掺量下，热再生应力吸收层混合料的动稳定度3 604次/mm，低温弯曲应变4 890με，且Over Test(OT)加载达到了1 200周期，聚合物胶粉复合改性沥青热再生料应力吸收层混合料具有优异的高温韧性和低温延展性与抗反射裂缝性能。

Experimental Study on Mechanical Properties and Road Performance of Hot Recycled Mixture in Stress Absorbing Layer

The fine aggregate in RAP has a large content of aged asphalt and high recycling value. The application of RAP to the stress-absorbing layer mixture can maximize the recycling value of RAP and reduce the construction cost of the stress-absorbing layer mixture. Using rutting test, small beam bending test, pre-cut semicircular bending tensile test, composite beam specimen torsion shear test, pull-out test, torsion shear fatigue test, Over Test to evaluate the high and low temperature performance of the hot recycled stress absorption layer mixture, inter-layer shear resistance, anti-shear fatigue performance and anti-reflective cracking performance. The results show that with the increase of the RAP blending ratio, the oil-stone ratio of the hot recycled stress absorption layer mixture decreases and the high temperature performance is enhanced, but increasing the RAP content leads to the low temperature bending strain, fracture energy, torsion shear strength, pull-out strength, torsion shear fatigue life and anti-reflective cracking performance of the hot recycled stress absorption layer mixture are all reduced. At 50 % RAP content, the dynamic stability of the hot recycled stress absorption layer mixture is 3604 times/mm, the low temperature bending strain is 4890 με, and the Over Test (OT) loading reaches 1200 cycles. The polymer rubber powder composite modified asphalt hot recycled material stress absorption layer mixture has excellent high temperature toughness and low temperature ductility and anti-reflective cracking performance.