INVESTIGATIONS ON THE MECHANICAL PROPERTIES OF HIGH STRENGTH SILICA-FUME CONCRETE (HSSC) MIXES AT DIFFERENT AGES

A. E., Sayed; , R. A. S, Mohamed

doi:10.21608/jesaun.2009.126486

INVESTIGATIONS ON THE MECHANICAL PROPERTIES OF HIGH STRENGTH SILICA-FUME CONCRETE (HSSC) MIXES AT DIFFERENT AGES

Document Type : Research Paper

Authors

Sayed A. E. ¹
Mohamed , R. A. S ²

¹ Associate Professor, Civil Engineering Department, Faculty of Engineering, El-Minia University, El-Minia, Egypt.

² Associate Professors, Civil Engineering Department, Faculty of Engineering, El-Minia University, El-Minia, Egypt.

10.21608/jesaun.2009.126486

Abstract

In recent years, some organization increasingly encourages the use of cementitious materials such as fly ash, slag and silica fume. Silica fume is a by-product in the manufacture of ferrosilicon and also of a silicon metal. Lately, some attention has been given to the use of condensed silica fume as a possible partial replacement for cement. The main objective of this investigation is to study the effect of the binder system containing different levels of silica-fume, as a partial replacement of cement, on the mechanical properties of high strength concrete and particularly, to determine the optimum content of silica-fume that maximize the strength and mechanical performance of HSSC. The work in this research focused on concrete mixes having water/binder ratio = 0.32 and constant total binder content (cement and silica) of 450 Kg/m3. The percentages of silica-fume that replaced cement in this research were: 0.0, 5.0, 10.0, 15.0, 20.0 and 25.0 %. Compressive, splitting and flexural strength tests were carried out at the age of 28, 59, 90,180 and 360 days to identify the mechanical properties of HSSC mixes at different ages. The effect of water/binder ratio on the compressive strength of HSSC mixes has been also examined. The modulus of elasticity of the produced concrete mixes at age of 28 days was determined. Test results of this research indicated that, the partial replacement of silica fume instead of cement in concrete mixes up to a ratio of 15 % effectively improves the mechanical properties of concrete and produces high compressive strength, beyond this limit, the compressive strength significantly decreased.

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