Effect of Accelerator Addition on the Rate of Compressive Strength Development of Concrete Using Treated Wastewater at a Concrete Strength of 25 MPa

Abstract

The world of civil engineering, especially in developed countries, has considered
reducing fresh water as a concrete mixture, especially due to the increasing
infrastructure development. The research aims to utilize ready mix wastewater that is
unused and will ultimately only be thrown away. The existence of time demands on the
progress of project implementation often forces concrete to show its optimal
performance faster than the time required for normal concrete. One way to get these
results is by using admixture in the concrete mixture. The research was conducted
using experimental methods at the Building Materials Laboratory, Department of Civil
Engineering, Faculty of Engineering, Janabadra University. The required test objects
were 36 samples with 3 variations and 4 ages of concrete. Variation 1 is concrete with
pure water, variation 2 is concrete with processed wastewater as a substitute for water,
and variation 3 is concrete with processed wastewater as a substitute for water +
accelerator additives at 2% of the total weight of cement. Calculation of concrete mix
planning using (SNI 03-2834-2000, 2000) with a plan compressive strength of 25 MPa.
The results showed that the processed waste water is still feasible to use for the
manufacture of new concrete although the compressive strength results decreased at
the age of 28 days by 3.88% when compared with pure water concrete. Concrete with
wastewater + accelerator provides an increase in compressive strength at the initial
age of concrete, namely 14.447% at 3 days; 12.087% at 7 days, and 5.671% at 28 days
when compared to concrete with pure water, thus providing a good solution to improve
the quality of concrete with wastewater at an early age. The compressive strength of
concrete increases with the age of concrete in all variations.