A probabilistic method for estimating the compressive strength of concrete containing weaker aggregates than mortar matrix is presented.
At first, for the aggregate of constant size, it is proposed that the strength of concrete can be estimated by determining the effective number of weak aggregates which exist randomly in a given cross section of the specimen. Then, an experimental program is performed to prove the propriety of the proposed method and to show the necessity to take into account the size of aggregate which is not considered in Bache's empirical equation. Moreover, for the mixed aggregate of different sizes, an equation for the estimation of the strength of concrete is also proposed as an extension of the case of constant size. On the basis of the present results, the compatibility of Bache's empirical equation is discussed.
