Title: Enhancing Acid Resistance Of Concrete By Varying Cement And Aggregate Types

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Publication: CIA

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Date: 2/13/2011

Abstract:
A research project has been undertaken at the Australian Centre for Construction Innovation at UNSW to investigate acid resistance of concretes using different types of cements and aggregates. This paper describes the experimental work with six concrete mixes. The cements used include Type-GP cement, Type-GB slag blended cement and ternary blended cement containing both silica fume and fly ash, or both silica fume and slag. Two types of coarse aggregates, crushed river gravel or limestone, were used in concrete mixes. Fine aggregates were silicious sand or crushed limestone. The 28-day compressive strengths of the six concretes were in the range of 45MPa to 58 MPa. Concrete cylinder samples were immersed in regularly refreshed 10%, 1% or 0.02% sulphuric acid solutions. The samples were periodically examined for changes in visual appearance, measured for mass change and tested for compressive strength. It was found that the limestone aggregate in concrete for acidic environments provided a means of reducing the rate of concrete degradation. The best acid resistance was found with the concrete using limestone aggregates and the ternary blend cement containing 7% silica fume and 33% fly ash.