Mesoscopic study of concrete I: generation of random aggregate structure and finite element mesh

Concrete is a composite material with a variety of inhomogeneities. Its composite behavior may be studied analytically using the mesoscopic approach which treats the concrete as a three-phase system consisting of coarse aggregate, mortar matrix with fine aggregate disserved in it, and interfacial zones between the coarse aggregate and the mortar matrix. For such mesoscopic study, it is first necessary to generate a random aggregate structure in which the shape, size and distribution of the aggregate particles resemble real concrete in the statistical sense. Then, if the composite structure is to be analyzed by the finite element method, a mesh for each of the three phases needs to be generated. In this paper, a procedure for generating random aggregate structures for rounded and angular aggregates based on the Monte Carlo random sampling principle is proposed and a method of mesh generation using the advancing front approach is developed. These are combined with a nonlinear finite element method for mesoscopic study of concrete whose methodology and results will be presented in part II of the paper. (C) 1998 Elsevier Science Ltd. All rights reserved.