填料中水泥用量对天然砾石骨料与沥青胶浆的粘附性影响

采用天然砾石骨料和石灰石粉填料配置心墙沥青混凝土时,存在粘附性与水稳定性不足的问题,考虑将水泥与石灰石粉混合,根据填料中水泥和石灰石粉的比例不同配置7种沥青胶浆,分别研究了其针入度、软化点和拉伸强度变化规律,再用光电比色法测得不同沥青胶浆裹附天然砾石骨料后沥青膜的剥落率,研究填料中水泥用量对沥青胶浆各项性能的影响。结果表明,水泥可提高沥青胶浆的粘度和适应变形能力,随着水泥用量的增加,沥青胶浆针入度先下降后上升,而软化点先升高后降低,拉伸强度和延度则一直上升;水泥可有效改善沥青胶浆与天然砾石骨料的粘附性,水泥用量越多,天然砾石骨料表面沥青胶浆膜剥落率越小;水泥用量仅需2%～4%,天然砾石骨料与沥青胶浆的粘附性就可达到碱性骨料的水平。

Effect of Cement Content in Filler on Adhesion of Natural Gravel Aggregate and Asphalt Mortar

When using natural gravel aggregate and limestone powder packing to configure the core wall asphalt concrete, there is a problem of insufficient adhesion and water stability. Therefore, mixing cement with limestone powder is considered. According to the proportion of the cement and limestone powder in the filler, 7 kinds of asphalt mortar were arranged in different proportions. The changes of the needle penetration, softening point and tensile strength were studied, and the peeling rate of the asphalt film was measured by the photoelectric colorimetric method, and the impact of the amount of cement in the filler on the performance of the asphalt mortar was studied. The results show that the cement can improve the viscosity and the adaptability to the deformation of the asphalt mortar. With the increase of water content, the penetration of the bitumen glue needle first descends and then rises, while the softening point rises first and then decreases, the tensile strength and ductility is always on the rising rule; The cement can effectively improve the viscosity of the asphalt mortar and the natural gravel aggregate. The more cement content is, the smaller the film peeling rate of the natural gravel aggregate surface is, the cement consumption is only 2% 4%, the adhesion of natural gravel aggregate and asphalt mortar can reach the level of alkaline aggregate.