SEAWATER CONCRETE : A SUSTAINABLE CONSTRUCTION MATERIAL

Abstract

The rising global cement consumption trend, the increasingly scarce but essential water resource required in the concrete mix and the effective wake-up call from the Indonesia sand ban suggest the impending need to search for a sustainable replacement for freshwater required in the production of concrete. The usage of local seawater as a sustainable alternative to replace freshwater required in the concrete mix is proposed in this study. However, the problem of reinforcement corrosion must be addressed. Currently, there is no well-researched corrosion preventive method that deals with concrete made from local seawater. The use of corrosion inhibitor, which is a kind of corrosion preventive method, is found preferred due to its advantages. Among the inhibitors, calcium nitrate is found as effective as the commonly used calcium nitrite by researchers but has not been examined thoroughly on its inhibiting properties, especially with the use of local seawater in the concrete mix. Three objectives have been set out in this study namely to determine the properties of the seawater concrete specimens, to investigate the effectiveness of calcium nitrate as a corrosion inhibitor and to conduct a cost analysis study on the hypothesized concrete based on the successful experiment results. Based on a limited exposure time and fixed number of tests conducted, seawater concrete specimen with calcium nitrate was found effective to inhibit reinforcement corrosion at certain dosages. The results also revealed that the use of local seawater and corrosion inhibitor investigated in this study did not affect the compressive strength of concrete. The cost analysis study conducted based on the experiment results concluded that normal seawater concrete is feasible for industrial usage while seawater reinforced concrete is uneconomical at the present moment. However, certain limitations should also be taken into consideration for critical evaluation of this study.