Model fitting to concrete carbonation data with non-zero initial carbonation depth

Abstract Carbonation is a key mechanism for deterioration of reinforced concrete structures. In design resistance to carbonation, the performance mixes often specified and measured in laboratory carbonation tests where initial sometimes present specimens. The coherent interpretation results from vital as they enable more accurate prediction structures situ. This paper assesses two different approaches considering depth when extracting coefficient testing. Experimental data compared models either approach using least squares regression. Both linear non-linear representations are shown fit well. gives larger estimate than approach, consistent with mathematical derivation equation. ramifications this difference will be most significant large relative front. modelling progression underpins performance-based new assessment existing infrastructure.