Title: Microstructure of Concrete Made with Blends of Fly Ash Cement and Waste Clay by Backscattered Electron Images

Author(s): M.I. Sanchez de Rojas, M. Frias, F.P. Marin, and J. Rivera

Publication: Symposium Paper

Volume: 242

Issue:

Appears on pages(s): 79-90

Keywords: concrete microstructure; fly ash; pozzolanic activity; precast concrete; waste clay material

DOI: 10.14359/18706

Date: 4/1/2007

Abstract:
Industrial waste clay materials, which are good pozzolans, can be used in place of cement in the manufacture of mortars and concretes. During the manufacturing process, which involves dehydration followed by firing at controlled temperatures ranging from 700 °C to 1000 °C, the clay minerals found in high proportions in the natural materials used to make bricks and similar products acquire pozzolanic properties. The present study examines the microstructure and morphology of the industrial concrete made with standard portland cement containing fly ash partially substituted with waste clay material, by backscattered electron images (BSE) and mercury porosimetry (MP) techniques. The microstructure of concrete test samples is not altered by the inclusion of clay discards and the pore size did not vary too, the only difference found was a slight decline in the proportion of larger diameter pores (over 0.1 micron).