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在多年冻土、重冰冻等地区的低温、大温差特殊条件下,沥青稳定碎石基层易产生低温收缩开裂,导致路面破坏。通过沥青稳定碎石大马歇尔试件的温度收缩、低温弯曲等试验,分析了矿料级配组成、沥青用量等因素对混合料低温抗裂性能的影响。分析得出,利用沥青稳定碎石的强度试验与马歇尔试验结果,综合确定的最佳沥青用量更为合理;矿料级配组成对混合料温度收缩系数的影响较小,空隙率是影响混合料温度收缩系数的主要因素;适量增加沥青用量可以显著提高沥青稳定碎石的弯拉强度和变形能力;单一指标无法科学评价沥青稳定碎石的低温抗裂性能。研究提出了以温度应力比和弯曲应变能为指标的沥青稳定碎石低温抗裂性能综合评价方法。
Under the special conditions of low temperature and heavy temperature difference in permafrost areas and heavy frozen areas, it is easy to produce low temperature shrinkage and cracking at the base of bitumen stabilized macadam, resulting in the destruction of pavement. Based on the experiments of temperature shrinkage and low temperature bending of large Marshall specimens of asphalt stabilized macadam, the effect of aggregate composition, asphalt content and other factors on the low temperature cracking resistance of the mixture was analyzed. The results showed that the best bitumen content was determined by using the strength test and Marshall test results of bitumen stabilized macadam. The influence of the mineral aggregate gradation on the temperature shrinkage coefficient of the mixture was small, Temperature shrinkage coefficient of the main factors; amount of asphalt can increase the amount of asphalt can significantly improve the bending strength and deformation capacity; a single index can not be scientifically evaluated asphalt stabilized macadam cracking at low temperature performance. The comprehensive evaluation method of low temperature cracking resistance of bitumen stabilized gravel based on temperature stress ratio and bending strain energy is proposed.