沥青混合料矿料间隙率的计算方法探讨

研究了我国的沥青混合料矿料间隙率(VMA)规定值和计算方法。研究发现：我国普遍使用的马歇尔设计方法。根据集料公称最大粒径规定的最小VMA值与美国马歇尔设计方法给定的最小VMA及美国Superpave设计方法规定的最小VMA值本质上是一致的。但计算方法却不同。因此，采用现行计算VMA的4种方法，计算了25种工地沥青混合料的VMA值。研究表明：我国的计算方法之一，用空隙率与总沥青用量的和计算的VMA明显偏大，有时难以排除不满足最小VMA要求的混合料。我国的粗集料用毛体积相对密度和细集料用表观相对密度计算VMA的方法和美国的方法所用公式形式一样，但用我国方法计箅的VMA比用美国方法计算的VMA均偏大。在实际使用时，建议按照细集料含量与细集料平均吸水率的乘积大小，修正我国计算公式。使之接近沥青混合料的真实VMA。

Discussion About Computation Method of Voids in Mineral Aggregate of Bituminous Mixtures (VMA)

The specified value of VMA and its computation method are (studied.) It is found that thespecified value of VMA in China is the same as that of VMA in America, but the computation methods are different. The VMA values of 25 kinds of job mixtures are computed with 4 kinds of different methods. The results show that the VMA value computed by percent air voids in bituminous mixture plus percent total bitumen volume in bituminous mixtures is bigger than the VMA value by America method. When the bulk specific gravity of coarse aggregate and the apparent specific gravity of fine aggregate are used to compute VMA value, the VMA value is greater than the VMA value by American method. It is suggested that the VMA value of computation by Chinese method is corrected by different products of the fine aggregate content and the average water content of fine aggregates.