Predicting the elastic properties of cement-based materials is dependent on three types of information for each phase: 1) how much of the phase is present, 2) how the phase is arranged in the microstructure, and 3) the values of the elastic moduli of the phase. Items number 1 and 2 are available in the CEMHYD3D output, while item 3 must be measured independently. Cement paste is extraordinarily complex elastically, and this complexity further increases in concrete, as aggregates are added.
A finite element package for computing the elastic moduli of composite materials has been written at NIST and has been available for several years (Garboczi, 1998). The program takes a 3-D digital image of a microstructure, assigns elastic moduli tensors to each voxel according to what material phase is present, and then computes the effective composite linear elastic moduli of the material. This program is highly optimized and has worked successfully for many different material microstructures, including ceramics ( Roberts and Garboczi, 2000), metal alloys (Roberts and Garboczi, 1999), closed and open cell foams (Roberts and Garboczi, 2002), gypsum plaster (Meille and Garboczi, 2001), oil-bearing rocks (Arns and others, 2002), and 2-D images of damaged concrete (Stutzman and others, 2001).