Abstract:
The objective of this research is to investigate the compressive strength of the
concrete that has sieved granite dust as replacement for sand in its mixture and the granite
dust is brought from the quarry of Thai Crushing Plant company (TCP) as a case study. The
sieved granite dust replaces some quantity of sand in the concrete mixture, ranging from the
ratio of 20 40 60 80 and 100 percentage (only sieved granite dust) by weight. The granite dust
will be sieved and arranged to get the similar grainsize distribution like the gradation of the
sand. The proportion of cement, sand and rock aggregate is 1:2:4 by weight and the watercement
ratio is 0.45, 0.55 and 0.65. The sieved granite dust has the specific gravity of 2.68 and
the absorption of 0.4; its grain size distribution is in compliance with ASTM C33. The average
value from the slump test is 8.8 centimeters. The concrete specimen is cylindrical shape with
15 centimeters in diameter and 30 centimeters in height, complied with ASTM C192. The time
duration for water curing is 7, 14, 21 and 28 days. The testing results of this research project
have shown that the replacement of sand by the sieved granite dust at 80 percentages provides
the most compressive strength: 368 ksc (w/c = 0.45), 329 ksc (w/c = 0.55) and 265 ksc (w/c
= 0.65). The normal concrete (mixed with sand only) has its different maximum compressive
strength for each w/c ratio: 395 ksc (w/c = 0.45), 321 ksc (w/c = 0.55) and 262 ksc (w/c = 0.65).
Then, in comparison, the variance is 1.1%, 2.5% and 6.8% respectively. Therefore the concrete
mixed with some sieved granite dust to replace some portion of sand indicate its application
use in practice for some types of structural work eg. the concrete type AA for special structure,
as stated in ASTM C150 which specifies the lowest limit for the ultimate compressive strength
of concrete to be 282 ksc. The applied compressive strength to be used is thus based on the
appropriate design of the replacement proportion of the sieved granite dust for sand and the
w/c ratio.