高温湿热地区沥青混合料抗水损害性能评价

通过室内试验，分析了沥青混合料高温浸水和级配离析对沥青混合料抗拉强度的影响．针对残留马歇尔稳定度指标及冻融劈裂残留强度试验的不足，提出以浸水四点弯曲试验来评价高温湿热地区沥青混合料抗水损害性能，着重探讨了不同离析程度（不同空隙率水平）对沥青混合料劈裂强度、四点弯曲强度的影响．研究结果表明，随着沥青混合料离析程度的增加，空隙率向2个极端发展，严重粗集料离析和严重细集料离析时混合料的空隙率相差10％左右；粗集料离析对劈裂强度和弯曲强度的影响大于细集料离析的影响；为了保证沥青混合料的抗水损害性能，应严格控制空隙率在4．5％～10％范围之外．采用高温浸水四点弯曲强度比作为沥青混合料水稳定性评价指标更为合理．

Evaluation of asphalt mixture resistance to water damage in high temperature hot and humid regions

This paper analyzes the influence of immersion with high temperature and grada- tional segregation on the tensile strength of asphalt mixture by tests in laboratory. The method of four points bending test in immersion is presented to evaluate the asphalt mix- ture＇s resistance to water damage at high temperature and humid regions due to the defi- ciency of retained Marshall stability index and the retained strength of freeze-thaw splitting test. It is mainly discussed the influence of the level of different porosities and gradational segregation on splitting tensile strength and four points bending strength of asphalt mix- ture. The results showed that the porosity develops toward two extremes as the level of segregation of asphalt mixture increases, and the error of porosity is about 10% as the seg- regations of coarse aggregate and fine aggregate seriously . The influence of segregation of coarse aggregate is more than the segregation of fine aggregate on splitting tensile strength and bending strength. The porosity should be controlled strictly beyond 4.5%-10% to en- sure that asphalt mixture＇s ability is enough to resist water damage. And the four pointsbending strength in immersion with high temperature can be used to evaluate water damage resistibility of asphalt mixtures more preferably.