Investigation of the Effect of using Salak Seeds as Coarse Aggregate in Concrete

This study described the effect of using salak seed waste as a substitute for coarse aggregate. The percentage of salak seed in concrete mixture became experimental variable to discover the best compressive strength of concrete. Quantitative study with experimental study was carried out at the Laboratory of Materials and Concrete, Faculty of Engineering, University. The design of experiment used a designed compressive strength of concrete of 20 Mpa. The experiment consisted of five variations in the percentage of salak seeds, namely 0%, 5%, 10%, 15%, and 20%. The slump test is carried out immediately after mixing the concrete in each proportion. Furthermore, 20 pieces of cylindrical concrete samples in each treatment were tested for 7,14,21 and 28 days. This method aims to compare the strength of each of the resulting concrete compositions. The results obtained showed that the use of salak seeds with a percentage of 5% and 10% gave a compressive strength value of 28 days which met the standard compressive strength of the design female. Meanwhile, the percentage of salak seeds 15% and 20% did not produce the planned compressive strength value. Therefore, salak seeds are suitable to be used as a substitute for coarse aggregate with a percentage of less than 10%. The higher the substitution of the mixture in the salak seed concrete, the lower the compressive strength of the concrete. The results of this study can be developed in green concrete studies that use waste.