Effects of the Incorporation of Municipal Solid Waste Incineration Fly Ash in Cement Pastes and Mortars. Part 2: Modeling.
Effects of the Incorporation of Municipal Solid Waste
Incineration Fly Ash in Cement Pastes and Mortars. Part
Remond, S.; Bentz, D. P.; Pimienta, P.
Cement and Concrete Research, Vol. 32, No. 4, 565-576,
cements; cement paste; mortar; solid waste; waste
materials; fly ash; hydration; leaching; microstructure;
diffusion; transport properties; durability
This work falls within the scope of a general problem
regarding the assessment of concretes manufactured from
waste materials. The main objective is to study the
long-term evolution of these materials during the
leaching process, using the cellular automata based
hydration model developed at the National Institute of
Standards and Technology. The work is based on the
analysis of mortars and cement pastes containing an
experimental waste: Municipal Solid Waste Incineration
fly ash (MSWI fly ash). After having determined the
mineralogical composition of the MSWI fly ash and its
interactions with cement during hydration (this work has
been presented in a former article), the phases
comprising the fly ash have been incorporated into the
hydration model. The increase in porosity of cement
pastes containing MSWI fly ash during the leaching
process has then been simulated. This study shows in
particular that the diffusion coefficient of these
pastes changes in a similar way to pure cement pastes.
Finally, a simplified leaching model has been developed.
This model shows in particular that the increase in the
diffusion coefficient in the damaged zone increases the
release of calcium. However, this release can be
simulated with a constant diffusion coefficient, greater
than the initial diffusion coefficient of the material.