Carbon Ash is a material produced from various objects, such as charcoal and the
smell of batteries. In Indonesia, each household consumes an average of 10 large dry
batteries (UM1), 5 medium-sized batteries (UM2) and 10 small-sized batteries (UM3)
in one year. based on the Decree of the Minister of Industry No.: 148/MISK/1985. dry
batteries can be classified into the category of Hazardous and Toxic Materials (B3). So
there needs to be an innovation to deal with these environmental problems. This study
aims to determine the compressive strength of concrete & the effect of adding carbon
ash as a partial replacement for sand in Fe' 21.5 MPa concrete. With variations in the
use of carbon ash as much as 0%, 10%, 30% and 50%. This research uses an
experimental method by replacing some of the fine aggregate in the form of sand with
carbon ash. Making concrete samples using a concrete cylinder with a diameter of 15
em and a height of 30 em. Mix Design planning refers to SNI Concrete Planning 03-
2834-2000. The results of the research show that the average compressive strength of
normal concrete is 34.59 MPa, while for the variation of the carbon ash mixture it is
10%: 38.15 MPa, 30%: 30.18 MPa and 50%: 29.90 MPa, so it can be concluded that
there is a fairly good increase. at 10% carbon ash variation.