  We use the periodic unfolding technique to derive corrector estimates for a
reaction-diffusion system describing concrete corrosion penetration in the
sewer pipes. The system, defined in a periodically-perforated domain, is
semi-linear, partially dissipative, and coupled via a non-linear ordinary
differential equation posed on the solid-water interface at the pore level.
After discussing the solvability of the pore scale model, we apply the periodic
unfolding techniques (adapted to treat the presence of perforations) not only
to get upscaled model equations, but also to prepare a proper framework for
getting a convergence rate (corrector estimates) of the averaging procedure.
