Abstract
The computing model for voids ratio of two-grading particles was developed as a basic model for multi-grading particles, which will contribute to reasonable concrete design method. The modeling was conducted using the voids ratio data obtained through the experiments with various sized glass beads. From the experimental data, the coefficient of particle interactions, k, was defined, and it was classified into three stages considering the distance of larger particles and the size of smaller particles. As the result of the formulation of the coefficient k, the voids ratio of two-grading particles having any size ratio and volume fraction can be computed. Moreover it was found that the boundary points between stage I and stage II is different in the case of real aggregate from that of glass beads. It was unified that the model can be applied to the voids ratio of real aggregate considering the difference of shape from glass beads.
