Influence of aggregate size and fraction on shrinkage induced micro-cracking of mortar and concrete

TL;DR

This study investigates how aggregate size and volume fraction influence shrinkage micro-cracking and permeability in concrete and mortar using nonlinear finite element analysis, revealing that larger aggregates and lower volume fractions increase permeability.

Contribution

It provides new insights into the effects of aggregate size and volume fraction on micro-cracking and permeability through detailed finite element modeling.

Findings

Larger aggregate size increases permeability.

Lower volume fraction increases permeability.

Micro-cracking is significantly affected by aggregate parameters.

Abstract

In this paper, the influence of aggregate size and volume fraction on shrinkage induced micro-cracking and permeability of concrete and mortar was investigated. Nonlinear finite element analyses of model concrete and mortar specimens were performed. The aggregate diameter was varied between 2 and 16 mm. Furthermore, a range of volume fractions between 0.1 and 0.5 was studied. The nonlinear analyses were based on a 2D lattice approach in which aggregates were simplified as monosized cylindrical inclusions. The analysis results were interpreted by means of crack width and change of permeability. The results show that increasing aggregate diameter (at equal volume fraction) and decreasing volume fraction (at equal aggregate diameter) greatly increases permeability.