# A free-boundary problem for concrete carbonation: Front nucleation and rigorous justification of the $t $-law of propagation

### Toyohiko Aiki

Japan's Women's University, Tokyo, Japan### Adrian Muntean

Eindhoven University of Technology, Netherlands

## Abstract

We study a one-dimensional free-boundary problem describing the penetration of carbonation fronts (free reaction-triggered interfaces) in concrete. Using suitable integral estimates for the free boundary and involved concentrations, we reach a twofold aim:

(1) We fill a fundamental gap by justifying rigorously the experimentally guessed $t $ asymptotic behavior. Previously we obtained the upper bound $s(t)≤C_{′}t $ for some constant $C_{′}$; now we show the optimality of the rate by proving the right nontrivial lower estimate, i.e. there exists $C_{′′}>0$ such that $s(t)≥C_{′′}t $.

(2) We obtain weak solutions to the free-boundary problem for the case when the measure of the initial domain vanishes. In this way, we allow for the *nucleation of the moving carbonation front* – a scenario that until now was open from the mathematical analysis point of view.

## Cite this article

Toyohiko Aiki, Adrian Muntean, A free-boundary problem for concrete carbonation: Front nucleation and rigorous justification of the $t $-law of propagation. Interfaces Free Bound. 15 (2013), no. 2, pp. 167–180

DOI 10.4171/IFB/299