The Potential Utilization of Candlenut Shell Waste as Coarse Aggregate Replacement in Concrete

Concrete is a mixture of cement, aggregate, water and additives. Concrete is a building material that is generally used in physical construction because it is easy to form and does not require expensive maintenance costs, compared to other materials. The development of science in the field of concrete technology, allows the use of candlenut shell as a substitute for some coarse aggregate in the concrete mixture, this is because the amount of material used in the concrete mixture, especially coarse aggregate, must be limited. This research uses candlenut shell as a comparison with normal concrete with a number of different variants of candlenut shell. This research is also to determine whether or not the candlenut shell is used as coarse aggregate in the concrete mixture. The method used in the mixed design of this research is SNI (Indonesian National Standard) and ASTM (American standard testing and materials) with a compressive strength of 20.75 MPa, a maximum coarse aggregate size of 20 mm and a cube-shaped test sample with a size of 15 cm x. 15 cm x 15 cm. As for the partial replacement variation of candlenut shells to coarse aggregates, namely the residue between 5.0%, 7.5%, 10.0%, 12.5%, 15.0%, 20.0% and 25.0%. Concrete compressive strength tests were carried out at the ages of 3, 7, 14 and 28 days. The results showed that the ratio of the compressive strength of normal concrete to that of concrete using candlenut shells experienced an increase in compressive strength. Where the compressive strength of the plan at the age of 28 days is 20.75 MPa, an increase of 27.29 MPa in normal concrete, while the concrete using candlenut shells has increased by 27.93 MPa at a variation of 10%