Effect of fly ash and silica fume on compression and fracture behaviors of concrete
- Hong Kong Polytechnic Univ., Kowloon (Hong Kong). Dept. of Civil and Structural Engineering
The effects of replacing cement by fly ash and silica fume on strength, compressive stress-strain relationship, and fracture behavior concrete were investigated. The investigation covered concrete mixes at different water-cementitious material ratios, which contained low and high volumes of fly ash, and with or without the addition of small amount of silica fume. It was found that fly ash substantially improved the post-peak compressive behavior of concrete, with a relatively smaller gradient in the descending part of the stress-strain curve. Low volumes of fly ash improved the tensile strength of concrete. High volume fly ash concrete showed slightly lower tensile strength, but higher values of crack tip opening displacement and final mid-span deflection in the fracture tests, with the corresponding K{sub IC} and G{sub F} values similar to or higher than the plain cement concrete. A small amount of silica fume had a large positive effect on the cylinder compressive strength and tensile strength but less on the cube compressive strength, while the fracture behavior of the resulting concrete was brittle. Improving interfacial bond between the paste and the aggregates in concrete had positive effects on K{sub IC}, but did not necessarily produce higher G{sub F} values.
- OSTI ID:
- 605725
- Journal Information:
- Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 2 Vol. 28; ISSN 0008-8846; ISSN CCNRAI
- Country of Publication:
- United States
- Language:
- English
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