Pore structure and its effect on strength of high-volume fly ash paste

Pastes made with different fly ash contents and water/binder ratios were te sted at different ages. The total porosity and pore size distribution were measured by mercury intrusion. The fractal dimension of pore-solid interfac e was first measured by small angle X-ray scattering (SAXS), The relationsh ip between porosity and strength for high-volume fly ash (HVFA) paste was d etermined. It is obtained that the pore size distribution affected both com pressive strength and flexural strength, bur the effects on compressive str ength and on flexural strength are different. Preliminary experimental resu lts indicated that strength was closely related to the pore surface fractal dimension. (C) 1999 Elsevier Science Ltd. All rights reserved.