Abstract :
Concrete is one of the most instrumental materials and is most often used in
the building and construction sector in Indonesia. Cement as one of the building
blocks of concrete can cause damage to the environment, ranging from the
collection of raw materials, the production process to ash pollution caused.
Therefore, an alternative material that can be used as a substitute for cement is to
utilize organic waste, such as coconut shell ash, considering that coconut shells
have the potential to cause organic waste that is still very poorly processed. In this
study, it is expected that the amount of cement use in concrete can be reduced by
investigating the potential of coconut shell ash as a percentage replacement material
for cement and its effect on the strong press of concrete.
The research method used is experimental studies in the laboratory. In this
study conducted 6 (six) variations in the percentage of coconut shell ash, which is
0% (control); 4%; 8%; 12%; 16%; and 20% of the initial cement weight with the
number of test objects each percentage variation amounts to 3. Strong testing of
concrete press is done when concrete reaches the age of 7 days, 14 days and 28
days.
The results of the study found that on the test of the normal concrete press
at 28 days is 300 kg / cm2 with an air cavity value of 0.023%. While the hard value
of the optimum press of concrete with coconut shell ash mixture at the age of 28
days is as much as 4% with a hard compress value of 319.11 kg / cm2 or up 6.37%
from normal concrete. While the smallest air cavity value is found in coconut shell
ash mixture 8% with a value of 0.011%.