Thermal induced stress and associated cracking in cement-based composite at elevated temperatures - Part I: thermal cracking around single inclusion

摘要

This paper presents the development and verification of 2-D mesoscopic thermoelastic damage model used to numerically quantify the thermal stresses and crack development of a cement-based composite subjected to elevated temperatures. The program is then used to study the thermal fracture behavior of a cement-based matrix with a single inclusion. The results show that the mechanisms of thermal damage and fracture of the composite depend on (i) the difference between the coefficients of thermal expansion (CTE) of the inclusion and the cement-based matrix, (ii) the strengths of materials, and (iii) the heterogeneity of materials at meso-scale. The thermal cracking is an evolution process from diffused damage, nucleation, and finally linkage of cracks. If the CTE of the inclusion is greater than that of the matrix, radial cracks will form in the matrix. On the other hand, inclusion cracks and tangential cracks at the interface between inclusion and matrix will form if the CTE of the inclusion is smaller than that of the matrix.