Fractal characteristic of recycled aggregate and its influence on physical property of recycled aggregate concrete

Fractal dimension is introduced to describe the complicated characteristics of recycled aggregate and their influence on properties of recycled concrete as an integrated indicator. The fractal dimensions of both particle outline and distribution of recycled aggregate have obvious self-similarity and fractal characteristics. The order of the bulk density, water absorption, and crushing index of recycled aggregate in particle group state is clearly and directly related to the fractal dimension of boundary line. Additionally, the fractal dimension of the distribution of recycled coarse aggregate in concrete decreases in order of natural aggregate, Type I, Type II, and Type III recycled coarse aggregate; smaller distribution dimension value represents more concentrated distribution of aggregate, and 7 and 28 days compressive strength of the corresponding recycled concrete increases. The fractal dimension method is an effective process to assess comprehensive performances of recycled aggregate and helpful to establish a quantitative evaluation criterion for its wide applications.