Title: Small-Angle Scattering Study of Concrete Microstructure as a Function of Silica Fume, Fly Ash, or Other Pozzolanic Additions

Author(s): A. J. Allen and R. A. Livingston

Publication: Symposium Paper

Volume: 153

Issue:

Appears on pages(s): 1179-1200

Keywords: fly ash; hydration; microstructure; pozzolans; silica fume; X-ray diffraction; Materials Research

DOI: 10.14359/1113

Date: 6/1/1995

Abstract:
Small-angle neutron and X-ray scattering techniques are being used in a systematic study of the development of concrete microstructure on the nanometer scale (1 to 1000 nm) as a function of the addition of fly ash, silica fume, or other pozzolanic materials. These methods yield direct measures of the fractal aspects of the material microstructure, including volume- and surface- fractal exponents and structure parameters within the calcium-silicate-hydrate gel. These variables are being evaluated for use in a classification system of microstructures. In the first phase of the program, the emphasis has been on the characterization of silica fume products both as separate phases and after reaction in concrete. The combination of small-angle scattering with a fractal interpretation scheme has been found to provide a resilient and powerful probe of the undisturbed statistically-significant microstructures in cementitious systems.