Concrete is an important part of a building. There are several materials
used in making concrete, one of them is fine aggregate. Material development is
now becoming a very important part. One of them is the use of iron sand as a
substitute for fine aggregate. The purpose of this study was to determine the effect
of the use of iron sand in concrete mixtures on concrete compressive strength.
Iron sand substitute in the concrete mixture was taken from 0%, 10%, 20%, 30%
and 40% of the weight of fine aggregate. The test sample was used on a concrete
cylinder with a diameter of 15 cm and a height of 30 cm with the age of 7 days
The results showed that the use of iron sand as the substitute for fine
aggregate in the mixture tended to decrease the compressive strength of concrete.
The average compressive strength of the 28 day-conversion from normal
concrete, 10%, 20%, 30% and 40% iron sand was 25.52 Mpa; 21.78 MPa; 20.06
MPa; 18.41 MPa; 16.09 Mpa. The decrease in concrete compressive strength was
caused by smaller absorption value of iron sand than ordinary sand which was
0.91% for iron sand and 3.74% for ordinary sand.