Modeling moisture ingress through simplified concrete crack geometries

This paper introduces a numerical model for ingress in cracked steel fibre reinforced concrete. Details of a simplified crack are preset in the model’s geometry using the cracked hinge model (CHM). The total crack length estimated using the CHM was, based on earlier work on conventional concrete, considered to have two parts; 1) a coalesced crack length which behaves as a free-surface for moisture ingress, and 2) an isolated microcracking length which resists ingress similarly to the bulk material.

Transport model results are compared to experimental results from steel fibre reinforced concrete wedge splitting specimens conditioned to 50% relative humidity, cracked to varying crack geometries, and exposed to liquid water. Water sorption was monitored by recording x-ray attenuation images over time.

Comparisons of results indicate the simplified crack geometry can accurately assess the impact cracks have on moisture ingress. Results from the transport model indicate the length of the isolated microcracks was approximately 19 mm for the investigated concrete composition.