Pengaruh Abu Sekam Sebagai Subtistusi Semen terhadap Slump Flow dan Berat Isi pada Flowing Concrete

In a construction project, the presence of dense reinforcement between reinforcement has its own problems when casting, namely when compaction it is very difficult to use a vibrator because of the density between the reinforcement. To minimize the negative impact of this, flowing concrete is made so that without using a vibrator, the concrete will self-compact properly. The constituent materials of flowing concrete are aggregate, cement and water. In the process of making cement production will produce carbon dioxide in the air, resulting in air pollution due to cement manufacture. To minimize the impact of air pollution due to cement, in this study, we tried one of the constituents of flowing concrete, namely partially substituted cement, so as to minimize air pollution. In this study, rice husk ash, which is the residue from burning rice husks, was used as a partial substitution of cement. The method used is conducting research in the laboratory. In this study, the variation of husk ash as a cement substitution was 0%, 5%, 7.5%, 10% and 12.5% with the addition of 1.5% superplasticizer. From the results of the study, the smallest diameter of slump flow was 53.17 cm in a mixture of 10% rice husk ash. The largest dry concrete density value is 2482.77 kg/m3 at 10% rice husk ash mixture. The conclusion that can be drawn is that based on slump flow and dry concrete density, the optimal substitution percentage for rice husk ash is 10 percent.