Gas permeability-based estimation of transport properties at concrete construction joints: A unified equivalent-aperture modeling framework

Construction joints in reinforced concrete can provide preferential pathways for aggressive agents and thereby reduce durability. This study evaluates a permeability-based analytical framework in which measured gas permeability is converted to an equivalent hydraulic aperture representing the transport behavior of the joint. The same inverse-derived descriptor is then used in gas, CO 2 diffusion/carbonation, and chloride-transport calculations. An empirical model-to-measurement ratio, β , summarizes the gap between predicted and measured penetration depths; it is not treated as a constitutive bonding parameter. Comparisons with controlled laboratory specimens show that the calculations overpredict the measured carbonation depths and the chloride penetration depths of jointed specimens under the tested conditions. Scenario-based service-life calculations suggest that joint condition may alter the balance between chloride ingress and carbonation in fly-ash concrete. Monte Carlo propagation of the reported aggregate permeability scatter expresses this result conditionally on assumed input distributions rather than as an empirical probability. Because several parameters are literature-based, joint-specific porosity and tortuosity were not measured, and no independent β calibration or external validation was available, the results are screening comparisons rather than design predictions or proven bounds. Within these limitations, the framework provides a common basis for comparing transport mechanisms in the tested construction-joint specimens.