Effect of Silica Fume and Slag on Compressive Strength and Abrasion Resistance of HVFA Concrete

Alaa M Rashad,Amr F Shaheen,Hosam El-Din H Seleem

doi:10.1007/s40069-013-0051-2

Abstract

In this study, portland cement (PC) has been partially replaced with a Class F fly ash (FA) at level of 70 % to produce high-volume FA (HVFA) concrete (F70). F70 was modified by replacing FA at levels of 10 and 20 % with silica fume (SF) and ground granulated blast-furnace slag (GGBS) and their equally combinations. All HVFA concrete types were compared to PC concrete. After curing for 7, 28, 90 and 180 days the specimens were tested in compression and abrasion. The various decomposition phases formed were identified using X-ray diffraction. The morphology of the formed hydrates was studied using scanning electron microscopy. The results indicated higher abrasion resistance of HVFA concrete blended with either SF or equally combinations of SF and GGBS, whilst lower abrasion resistance was noted in HVFA blended with GGBS.

Highlights

The use of high-volume fly ash (HVFA) concrete is one of the solutions to eliminate the environmental degradations being caused by cement industry
This paper presents the compressive strength and the abrasion resistance of HVFA concrete in which cement was partially replaced with FA at level of 70 %
The inclusion of FA was 70 % as cement replacement; 10 and 20 % from FA was partially replaced with individual silica fume (SF), individual slag and combinations of SF and slag

Summary

Introduction

The use of high-volume fly ash (HVFA) concrete is one of the solutions to eliminate the environmental degradations being caused by cement industry. Sivasundaram et al (1990) believed that the replacing cement ratio above 30 % with FA in concrete is defined as HVFA concrete. Dunstan et al (1992) believed that above 40 % FA in concrete defined as HVFA concrete is suitable. Some authors suggested that the concrete may be defined as HVFA concrete when the quantity of FA exceeds of cement in cementitious material (i.e. the quantity of FA is more than 50 %). Bilodeau and Malhotra (1992a) suggested that the quantity of FA in HVFA concrete must be 50–70 %, namely the volume of FA is larger than cement in concrete. LEED (PCA 2005) pointed that HVFA concrete included up to 40 % of FA in cement

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