BEHAVIOUR OF PERIWINKLE SHELL ASH BLENDED CEMENT CONCRETE IN SULPHURIC ACID ENVIRONMENT

This paper presents the influence of sulphuric acid on compressive strength of concrete made with cement blended with periwinkle shell ash (PSA). The cement component was replaced with PSA at 0 %, 5 %, 10 %, 15 % and 20 %. Concrete mix ratio of 1:2:4 and a constant water cement ratio of 0.6 was used. A total of 180 cube specimens (150mm x 150mm x 150mm) were cast and tested for compressive strength at 7, 14, 21 and 28 days of immersion in potable tap water (as control) and (5 % and 10 %) sulphuric acid solutions.  Test results showed that the compressive strength increased with age and decreased with PSA content for specimen cured in water (control); while for specimen cured in sulphuric acid solutions, the compressive strength decreased with age, PSA content as well as sulphuric acid content. The statistical analysis of variance showed that the sulphuric acid concentrations, PSA contents and curing age have effect on the concrete compressive strength. Regardless of the concentration of exposure conditions, it is concluded that PSA did not lighten the adverse effects of sulphuric acid on the compressive strength of cement blended with PSA. http://dx.doi.org/10.4314/njt.v37i2. 5