倒装式沥青路面级配碎石过渡层渗水特性分析

Analysis on Permeability of Transition Layer of Graded Crushed Stone in Inverted Asphalt Pavement

针对路面结构内部自由水易诱发路面出现唧浆、松散及冻融等病害,研究了倒装式沥青路面级配碎石过渡层的排水性能,测试了级配碎石试件渗水系数。采用重型击实法成型试件,采用路面渗水仪测试其渗水系数,分析了主要影响因素(如主要筛孔通过率、空隙率等)对级配碎石混合料渗水性能的影响,进而拟合了其渗水系数预估公式。研究表明:空隙率及4.75mm以下筛孔通过率对渗水系数的影响大于4.75mm以上筛孔通过率,过渡层级配碎石空隙率宜分布在13%~15%内;基于各因素对渗水系数影响程度的综合分析,采用关键因素(关键筛孔通过率和空隙率等)回归得出了渗水系数预估公式,该公式适用于0.075mm筛孔通过率在3%~14%范围内的级配碎石渗水系数预估,可为倒装式沥青路面过渡层级配碎石的设计、渗水系数现场测试提供指导。

In view that pumping,loosing and freeze-thaw damage in bituminous pavements are caused by free water in pavement structures,the draining performance of the transition layer with graded crushed stone for inverted asphalt pavement is studied,and the permeability coefficient of graded crushed stone specimens is tested.The specimen is prepared by heavy compaction method,and the permeability factor is tested by pavement seepage meter,and the main impact factors(such as sieve pass ratio,void ratio etc.)on the permeability performance is analyzed,and further the formula for estimating the permeability coefficient of graded crushed stone is worked out.The research shows:the effect of void and the sieve pass ratio of below 4.75 mm on permeability factor is larger than that of the sieve pass ratio of over 4.75 mm,and it is suggested that the void ratio in transition layer is better when between 13%~15%.Moreover,based on the correlation analysis of various factors and permeability coefficient,the formula for estimating the permeability coefficient is obtained by using the void ratio and critical sieve pass rate.The formula is suitable for estimating the permeability coefficient of the graded crushed stone when the 0.075 mm sieve pass ratio ranges from 3%~14%,which can provide reference for design of graded crushed stone for transition layer if inverted asphalt pavement and site test of permeability factor.