The development of today's concrete technology has progressed rapidly
with the existence of tools which can help in simplifying and accelerating the work
of concrete stirring. In the execution of concrete work, many people have used the
concrete mixer. This machine makes the mixture more evenly and perfectly mixed.
Moreover, the stirring duration and its speed also significantly affect the result. In
PBI 71-6.2.3., it is mentioned that the least stirring durationis 1.5-3.5 minutes after
all materials have been inserted into the stirring drum. The research problem was
what the effect of concrete stirring using concrete mixer toward concrete
compressive strength of fc' 25 Mpa aged 7 days. The research aimed to find out the
concrete compressive strength of fc' 25 Mpa related to the stirring length using the
concrete mixer with the time variations of 1 minute, 1.5 minutes, 2.5 minutes, 3.5
minutes, and 4 minutes. The research result revealed that in 1 minute time variation,
the compressive strength was 22.565 Mpa. In 1.5 minutes time variation, it was
24.983 Mpa, and the maximal compressive strength of 25.252 Mpa was obtained in
2.5 and 3.5 minutes time variation.