THE EFFECT OF USING HIGH VOLUME FLYASH (HVFA) ON THE PROPERTIES OF FRESH MORTAR

Abstract

This study aims to understand the effect of using High Volume Fly Ash (HVFA) on the
properties of fresh mortar. Mortar properties such as cement paste setting time, fresh mortar flow value,
and mortar compressive strength were tested in this study. The results showed that the higher the fly ash
content used in the mixture, the longer the paste setting time occurred. The initial bonding time of the
cement paste with the control specimen, fly ash content of 0, 50 and 75% occurred at the 131st minute,
17.5th minute, 15th minute and 28th minute, respectively. The final binding time of the control sample
cement paste, fly ash content of 0, 50 and 75% occurred in the 210th minute, 50th minute, 70th minute
and 95th minute, respectively. The results showed that the use of High-Volume Fly Ash (HVFA) could
increase the workability of fresh mortar. This is evidenced by the use of fly ash 50% causes an increase in
flow value as much as 20.5% and the use of fly ash 75% causes an increase in flow value as much as
42.7%. Research proves that the higher the fly ash content used in the mixture, the lower the compressive
strength value produced by the mortar. The results of the compressive strength test of HVFA mortar with
control sample specimens, fly ash content of 0, 50 and 75% respectively were 16.6 Mpa, 6.3 Mpa, 5.2
Mpa, and 4.5 Mpa