THE UTILIZATION OF BLACK STONE WASTE AS AN ALTERNATIVE MATERIAL TO REPLACE PARTIAL CEMENT AND AGGREGATE IN CONCRETE I. W. Gde Erick Triswandana(1). Putu Aryastana(1). Christian Winata(2). I Made Ardantha(1).
(1) Warmadewa University, Bali
(2) National Central University, Taiwan
Abstract
Concrete is the most common construction material used to improve infrastructure in developing countries, especially in the Southeast Asia Region. Every ton of cement produced leads to about 0.9 tons of CO2 emissions with a typical cubic yard of concrete contains around 10% by weight of cement. Besides, the availability of black stone waste has increased significantly in Bali Province. This is due to the waste product from building ornament craftsmen in the form of powder, granules, chunks up to 30% of total production along with the absence of a waste management regulation, which has the potential to cause damage to the surrounding environment. It is known that black stone contains 40 - 75% of silica compound which has the potential to replace partially cement and aggregate in concrete. To address those issues, this study aims to utilize black stone waste as cement and aggregate replacement with a weight ratio of cement: fine aggregate: the coarse aggregate of 1: 2: 3 and w/c ratio kept at 0.4, 0.45, 0.5 respectively. The black stone powder was substituted as cement by 5%, 7.5%, and 10%. Meanwhile, the black stone aggregate was replaced by 25% of fine aggregate and 25%, 50% of coarse aggregate. The cylindrical specimens with a diameter of 150 mm and a height of 300 mm were tested on compressive strength and unit weight at 28 days of water curing to compare the effect of replacing black stone waste in concrete. A mixture without black stone waste was used as a control mixture. The results showed that 7.5% of black stone powder (BSP) and 25% of the black stone aggregate (BSA) achieved the highest strength compared to the control mixture when the w/c ratio kept at 0.4, 0.45, respectively. On the contrary, the compressive strength was significantly reduced by utilizing black stone waste at the w/c ratio 0.5. Thus, it can be concluded that cement and aggregates could be replaced by BSP not more than 7.5% and BSA not more than 25%, respectively. It is expected that black
Keywords: Black stone waste, cement replacement, aggregate replacement, water-cement ratio, compressive strength
Topic: Menggali Potensi Lokasi Sebagai Keunggulan Daya Saing Masyarakat
