Potential of Tabas Stone Waste as Additional Material of Concrete for Coastal Protection Structures

Abstract

The coast has natural protection, but if this natural protection is damaged, the coast can be protected with coastal structures. Concrete is one of the main materials for coastal protection structures such as breakwaters, jetties, groins and revetments. Concrete used in coastal environments must have high strength performance to face the challenges of corrosive seawater,
high humidity, and extreme temperature changes. Tabas stone is a Basaltic Scoria stone resulting from the eruption of Mount Agung which is used by the people of Bali as an ornament in Balinese buildings. Tabas stone pieces that do not match the size are discarded and become waste. In this study, tabas stone waste was used as an additional material for fine aggregate of 0%, 10%, 20% with a concrete design compressive strength of 42 MPa. Cylindrical samples were produced then soaked in the sea and at the river mouth. Furthermore, the samples were tested to be compared with concrete samples with curing in standard water conditions at the age of 28 days. The test results showed that the effect of seawater and brackish water immersion caused a significant decrease in the compressive strength of the concrete. The addition of the percentage of tabas stone also caused a decrease in the compressive strength of the concrete. Thus, tabas stone have small potential to be used as an additional material for concrete filler for coastal building construction.