基于不同试验类型的铁屑对沥青混合料愈合能力的影响研究

基于铁屑对混合料愈合能力的促进作用,对铁屑沥青混合料的SCB半圆弯曲试验和四点弯曲疲劳试验的愈合结果进行了对比分析,采用二次拟合方法建立了铁屑沥青混合料愈合方程,旨在探究不同试验类型对铁屑促进混合料愈合效果的影响及影响规律。研究结果表明:对于SCB半圆弯曲试验,有无铁屑条件下的混合料愈合能力相差6.34%。对于四点弯曲疲劳试验,有无铁屑条件下的混合料愈合能力相差22.01%,这说明铁屑对四点疲劳试验试件的愈合增强作用要大于对SCB半圆弯曲试验试件的愈合增强作用。二次愈合方程的相关系数R^2分别为0.88239和0.95592,表明采用二次拟合方法建立的预估模型,可以较好的体现铁屑对沥青混合料愈合能力的影响规律。最后根据愈合方程得到四点弯曲疲劳愈合试验的最佳铁屑掺量为8.4%。

Study on The Effect of Iron Scrap on Healing Ability of Asphalt Mixture Based on Different Test Types

Based on the promoting effect of iron scrap on healing ability of asphalt mixture,the results of SCB semi-circular bending test and four-point bending fatigue test of iron scrap asphalt mixture were compared and analyzed.The quadratic fitting was used to establish the healing equation of iron scrap asphalt mixture.The purpose is to explore the effect of damage form on the effect of iron debris on the mixture healing.The results show that for SCB semicircle bending test,the healing ability of mixture with or without iron scrap is 6.34%.For the four-point bending fatigue test,the healing ability of mixture with or without iron scraps is 22.01%,which indicates that the healing enhancement effect of iron scrap on four-point fatigue test specimen is greater than that on SCB semi-circular bending specimen.The correlation coefficient R^2 of the quadratic fitting equation is 0.88239 and 0.95592,respectively,which indicates that the prediction model established by the quadratic fitting method can better reflect the influence of iron debris on the healing ability of asphalt mixture.Finally,according to the healing equation,the best amount of iron scrap in the four-point bending fatigue healing test is 8.4%.