煤基沥青在沥青混凝土路面中技术应用研究

Research on Technical Application of Coal-Based Asphalt in Asphalt Concrete Pavement

摘要:

针对甘肃平凉地区冬冷夏热的气候特征与道路建设需求，系统探讨了以煤基沥青部分替代石油沥青的技术可行性。通过对煤基沥青与70号道路石油沥青的性能对比，明确了煤基沥青高软化点、低针入度、低延度及高黏度的特性，其“高沥青质与胶质、低油分”的化学组成是导致高温性能优而低温性能差的根本原因。基于AC-13级配，通过马歇尔试验确定了不同复配比例的最佳沥青用量，并系统评价了混合料的路用性能。结果表明，随煤基沥青掺量增加，混合料高温稳定性显著提升，但低温抗裂性与水稳定性下降。确定40%为潜力掺量，但其低温性能不满足要求。采用外掺3% SBS进行改性后，混合料低温弯拉应变达2 600 με，动稳定度提升至2 500次/mm，水稳定性同步改善，综合性能全面达标。基于室内研究，铺筑了试验段，明确了适用于高黏度改性沥青的施工工艺参数。现场检测与观测表明路面状况良好。该方案材料成本与纯石油沥青混合料基本持平，同时具有节约石油资源、消纳固废的环境效益，为煤基沥青在寒冷地区的应用提供了技术依据。

Abstract:

In response to the climate characteristics of cold winters and hot summers and the needs of road construction in the Pingliang region of Gansu Province, the technical feasibility of partially replacing petroleum asphalt with coal-based asphalt is systematically discussed. Through a performance comparison between coal-based asphalt and 70# road petroleum asphalt, the characteristics of high softening point, low penetration, low ductility and high viscosity of the coal-based asphalt are clarified. Its chemical composition of “higher asphaltene and resin contents with low oil content” is identified as the fundamental reason for its superior high-temperature performance but poor low-temperature performance. Based on the AC-13 gradation, the optimal asphalt content for different blending ratios is determined via Marshall tests, and the pavement performance of the mixtures is systematically evaluated. The results indicate that as the coal-based asphalt content increases, the high-temperature stability of the mixture significantly improves, but its low-temperature crack resistance and moisture stability decline. A 40% coal-based asphalt content is identified as a potential blending ratio, although its low-temperature performance fails to meet requirements. After modification by adding 3% SBS, the low-temperature flexural tensile strain of the mixture reaches 2 600 με, its dynamic stability is enhanced to 2 500 cycles/mm, and its moisture stability is improved simultaneously. The comprehensive performances meet all standards. Based on laboratory research, a test section is paved in order to define the construction process parameters suitable for high-viscosity modified asphalt. The field inspections and observations indicate that the pavement condition is satisfactory. The material cost of this scheme is basically comparable to that of pure petroleum asphalt mixtures, while offering environmental benefits such as conserving petroleum resources and absorbing solid waste, which provides a technical basis for the application of coal-based asphalt in cold regions.