Abstract
This study examines durability and mechanical properties of sustainable self-consolidating concrete (SCC) in which 80% of the cement is replaced with combinations of recycled industrial by-products including fly ash, silica fume, and ground granulated blast furnace slag (GGBS). The water to binder (w/b) ratio of SCC mixes studies was maintained at 0.36. The study proposes empirical relationships to predict 28-day compressive strengths based on the results of three-day and seven-day compressive strengths. In addition, the chloride penetration resistance of the various sustainable SCC mixes was determined after three days, seven days, and 28 days of moist curing of concrete standards. It was concluded that fly ash, silica fume, and GGBS contribute favorably to enhancing strength development, fresh properties, and durability of SCC in comparison to ordinary Portland cement (OPC). The compressive strength of the sustainable SCC mixes falls within ranges suitable for structural engineering applications. Replacing cement with 15% silica fume produced a 28-day average compressive strength of 95.3 MPa, which is 44.2% higher than the control mix. Replacing cement with 15% or 20% silica fume reduced the chloride ion permeability to very low amounts compared to high permeability in a control mix.
Highlights
The construction industry contributes to environmental pollution including the production of cement used in the concrete industry
This study examines the properties of sustainable self-consolidating concrete (SCC) in which up to 80% of the cement is replaced with various combinations of fly ash, silica fume, and ground granulated blast furnace slag (GGBS)
In quaternary mixes GM1 to Green Mix 7 (GM7), 80% of the cement was replaced with combinations of fly ash, silica fume, and GGBS and the cement content is maintained at 96 kg/m3
Summary
The construction industry contributes to environmental pollution including the production of cement used in the concrete industry. 28-day compressive strength compared to a control mix [2,3] Both studies indicate that chloride penetration resistance is enhanced by replacing cement with 20% fly ash. It was found that replacing 15% of cement by silica fume resulted in a 28-day compressive strength of 95.3 MPa, which was 44% higher than the control SCC mix examined in the study by Mohamed and Najm [6]. Due to their spherical morphology, which reduces inter-particle friction, both silica fume and fly ash enhance workability and is essential for producing high strength concrete. The resistance to chloride penetration of the various SCC mixes is examined after 1, 3, 7, 28, and 40 days of curing
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