PENGARUH PENGGANTIAN SEBAGIAN SEMEN DENGAN FLY ASH TERHADAP KUAT TEKAN MORTAR SKBB 30% PADA UMUR 14, 28 DAN 56 HARI

The development of construction development in Indonesia in recent years has accelerated with the increasing need for infrastructure and public facilities in order to build Indonesia into a developed country. In the development of development in Indonesia, there is innovation in the use of mortar as an adhesive material in buildings. This study aims to determine the compressive strength of 30% SKBB mortar with fly ash variations of 0%, 5%, 15%, and 25%. The mortar compressive strength test was conducted at the age of 14 days, 28 days, and 56 days. The research method used is experimental by making mortar size 50 mm x 50 mm x 50 mm. Treatment of test specimens was carried out by curing during the test period. The materials used in making mortar are cement, sand, used tire rubber shavings, fly ash, and water. Compressive strength testing was conducted in accordance with SNI 03-6825-2002. The highest compressive strength value was produced in 30% SKBB mortar with the use of 15% fly ash at the age of 56 days with a compressive strength of 4.79 MPa. Based on the results of the study it can be concluded that 15% fly ash variation can increase the compressive strength of mortar, but at 25% fly ash variation can reduce the compressive strength value of mortar.