FLY ASH WASTE FOR OBTAINING BUILDING MATERIALS WITH IMPROVED DURABILITY
MARIA HARJA *, MIHAELA CAFTANACHI, MIHAELA FANACHE VASILIU, GABRIELA CIOBANU Gheorghe Asachi Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73, Prof.dr.doc. D. Mangeron Blvd., Iasi 700050, Romania
*Corresponding author: mharja@tuiasi.ro
The fly ash wastes (materials rich in silica, aluminum, and iron) could be advanced valorized by using as pozzolanic materials in the formulation of mortar and concrete. The partial hydrolysis of its, during alkali activation process, gel formation, and polycondensation produce the compulsory properties. The study had as objective to determine the optimal conditions, and the relationships between the fly ash modifying parameters, particle size and morphology, and behavior in chemical agents of the mortar obtained from different wastes. The alkali activation process involved varying the liquid/solid ratio (quantities of liquid phase) and the concentration of the NaOH solution (8 - 12 M). The samples' morphologies, particle size distribution, Blaine surface values, and crystallography were significant changes as a result of the activation, as demonstrated by XRD and SEM analysis. The durability values were substantially improved comparatively with building materials on the base of cement. As a result, treated fly ash is suitable as a potential building material, saving disposal-related issues. Using treated fly ash is environmentally friendly method conserving a large amount of cement, used in the production of building materials and reducing the CO2 emissions.
