Unit Weight and Elastic Modulus of Concrete utilizing Volcanic Stone Waste as Coarse Aggregate

Unit weight and elastic modulus of concrete utilizing volcanic stone waste (VSW) as coarse aggregate have been studied at 28 days of hydration. The origin of VSW was the residual of volcanic stone processing for making the handmade ornaments of traditional Balinese buildings. Three types of concrete mixture compositions were made by varying the proportion of cement, fine aggregate and coarse aggregate in concrete. Each mixture composition stirred using four variations of water/cement (w/c) ratio. For each variation in w/c, five cylindrical specimens with a diameter of 150 mm and a height of 300 mm were made to measure the unit weight and modulus of elasticity of concrete specimens after 28 days of hydration. The result shows that the unit weight and the elastic modulus of concrete decrease with increasing w/c at fixed proportions of cement and aggregates and increase with increasing proportion of aggregates at fixed w/c. The increase in elastic modulus with an increase in the a/c ratio for a fixed w/c ratio is more noticeable for a w/c ratio of more than 0.6. Moreover, the elastic modulus increases correspondingly with an increase in unit weight for a given a/c ratio.