Further Development of the Distinct Lattice Spring Model for Quasi-brittle Crack Propagation in Conc

Qin Li, Gao-Feng Zhao, Jijian Lian

This paper further extends the ability of the distinct lattice spring model (DLSM) to predict quasi-brittle crackpropagation in concrete. In contrast to brittle crack propagation, most experimental results confirm that thecrack propagation in concrete is quasi-brittle. The DLSM was originally developed to study the brittle fracturingof rock. Whether and how it could be applied to quasi-brittle crack propagation has not been systematicallystudied. In this work, considering aspects of the geometric non-uniformity, material heterogeneity and micromechanical constitutive model, the ability of the DLSM to solve quasi-brittle crack propagation has been systematically investigated. The main contributions of this work are that it (1) confirmed the necessary for theDLSM to have a new micro-mechanical constitutive model to solve the quasi-brittle crack propagation problem;(2) established a new micro-mechanical constitutive model for quasi-brittle crack propagation; and (3) proposeda formula for the relationship between the micromechanical and macroscopic material parameters of the concrete. The new micromechanical constitutive model proposed in this paper has been systematically verified bythree-point bending experimental results of various grades of concrete. Finally, the new constitutive model hasbeen adopted to analyse the cracking of the concrete lining.