计算混凝土中邻近集料表面间距平均值的体视学方法

Stereological method of calculating the average value of surface spacing between the neighboring aggregate grains in concrete

借助于体视学中的平均自由程公式,给出了计算水泥基复合材料平均邻近集料表面间距平均值的方法,并给出了两种计算集料的表面积的方法:基于集料表面积近似计算的解析解法和混凝土样品截面的线采样分析法.结果表明:采用截面线采样分析法能够很好地近似计算混凝土中邻近集料表面间距的平均值,也提供了一种计算不规则形状集料粒子体系表面积的思路,混凝土中邻近集料表面间距的平均值大小只与混凝土中集料的体积分数、集料的密度以及集料的比表面积有关,而与集料的粒径分布(或粒径范围)无关.

The equation of the mean free path in stereology was introduced into the calculation of the average value of surface spacing between neighboring aggregate grains in concrete. Two methods to calculate the aggregate surface area of concrete are given. One is an analytical solution based on an approximate calculation of the surface area of the aggregate while the other is a lineal sampling method based on the sectional plane of concrete. The results showed that the lineal sampling method on the sectional plane is an ideal approximate approach to study the mean value of surface spacing between neighboring aggregate grains in concrete and the method actually provides an approach to calculate the aggregate surface area with irregular shapes in concrete. Further analysis of the equation of mean free path demonstrated that the mean value of surface spacing between neighboring aggregate grains in concrete is dependent not on the particle size distribution （ or size range） of the aggregate, but on the volume fraction, density and the specific surface area of the aggregate investigated.