Evaluation of the Sulphuric Acid Resistance of Contemporary Concretes
R. Munn, ZA Chang, XA. Song, and M. Marosszeky
Appears on pages(s):
concrete; fly ash; limestone aggregate;
loss of strength and mass; silica fume; slag; sulphuric acid
A research project was undertaken at the Australian Centre for Construction Innovation, University of New South Wales to investigate the sulphuric acid resistance of various concretes using different types of cements and aggregates. The cements included a general purpose portland cement, a slag-blended cement, and ternary blended cements containing both silica fume and fly ash, or both silica fume and slag. Two combinations of aggregates, limestone coarse and fine aggregates and, crushed river gravel coarse aggregates and silica sands, were used in the concrete mixtures. The standard compressive strengths of the concretes tested at 28 days were in the range of 45 to 58 MPa. Concrete cylinders were immersed in regularly refreshed 1% and 0.02% sulphuric acid solutions. These cylinders were assessed by visual inspection of the surface deterioration, measuring mass change and testing for crushing load during the immersion period. It is found that the use of limestone aggregates was a quite promising option in order to reduce the rate of concrete degradation in acidic environments. 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.