04-09-2012, 01:20 PM
Stone crusher dust as a fine aggregate in Concrete for paving blocks
replacement of sand with stone dust.pdf (Size: 415.64 KB / Downloads: 397)
ABSTRACT
Concrete paving blocks are ideal materials on the footpaths for easy laying, better look and
finish. In this paper, a parametric experimental study for producing paving blocks using
crusher dust is presented. Some of the physical and mechanical properties of paving blocks
with fine aggregate (sand) replaced by various percentages of crusher dust are investigated.
The test results shows that the replacement fine aggregate by crusher dust up to 50% by
weight has a negligible effect on the reduction of any physical and mechanical properties
while there is a saving of 56% of money. The percentage of saving was less but highly
beneficial for mass production of paving blocks. The shaving would be more if the sand
availability is at a greater distance. This also reduces the burden of dumping crusher dust on
earth which reduces environmental pollution.
Introduction
A lot of facelift is being is given to roads, footpaths along with roadside. Concrete paving blocks are ideal materials on the footpaths for easy laying, better look and finish. Cement
concrete paving blocks are precast solid products made out of cement concrete. The product
is made in various sizes and shapes viz. rectangular, square, and round blocks of different
dimensions with designs for interlocking of adjacent paving blocks. The raw materials
require for manufactures of the product are Portland cement and aggregates which are
available locally in every part of the country. Market potential cement concretes paving
blocks find applications in pavements, footpaths, gardens, passengers waiting sheds, busstops,
industry and other public places. The product is commonly used in urban areas for the
above applications. Hence, the unit may be set up in urban and semiurban
areas, near the
market.
Water Absorption: As per IS: 15658:2006 water absorption of concrete paving block
should be less than 7%. But maximum water absorption among all groups was found to be
1.56% in FC75 which is much less than the requirement also it comply maximum water
absorption requirement less than 10% as per IS: 2185 (PartI)
2005.
Weight loss in Acid Solution: From the Weight loss of samples immersed in acid solution
(H2So4) with 1% of water after 30 days it was found the loss in weight in the normal concrete
was slightly higher that the concrete containing crusher dust and also weight loss decreases as
percentage of crusher dust increases. Difference in weight loss of normal concrete in the
concrete containing 100% crusher dust (FC.100) is found to be 3.5 % approximately. The loss
in weight up to FC50 is insignificant.
Weight Loss in Alkali Solution: Weight loss of samples in alkali solution (NaOH) with 4%
of water after 30 days in the normal concrete was found to be smaller than the concrete
containing crusher dust but differences are very small about 0.6%. It may be due to the
crusher dust have greater tendency of reacting with alkali solution than the normal sand i.e.
resistance of crusher dust against alkali resistance is less than the normal sand.
Density: Density of the normal concrete was found to be less than the density of the concrete
containing crusher dust but specific gravity of the sand used for the preparation of concrete
was found to be higher than the specific gravity of crusher dust. Density of the specimen
FC100 is found to be less than the normal concrete. The specimen FC50 &FC75 shows higher
density and it may be due to difference in compaction during casting or may be due to slight
variation in homogeneous in the mix. The code IS 2185 (part 1) : 2005 specified for solid
concrete block grade C density should not be less than 1800 Kg/m 3 .
Flow /Slump (water requirement): The slump value had been measured during the casting
of specimen. The slump value decreases as the percentage of crusher dust increases. This
reflects as percentage of crusher dust increases the water requirement increases and thus slum
value decreases which may due texture of crusher dust. Generally crusher dust has rough
texture than sand. The aggregate having rough texture requires more water for surface
weighting. Thus some water is consumed for surface weighting of crusher dust and the net
water available get decreases for workability. As per the IS 15658:2006 concrete paving
block may be prepared with concrete having zero slumps. If the water requirement increases
and slump decreases, addition of crusher dust may solve the problem which will not affect the
physical properties.
Conclusion
Replacement fine aggregate by crusher dust up to 50% by weight has a negligible effect on
the reduction of any physical and mechanical properties like compressive strength, flexural
strength, split tensile strength etc. Water absorption is well below the limit as per Indian
codes. Durability test shows no variation for different replacements of crusher dust. There is a
shaving of 56% of money if sand is replaced by crusher dust. The percentage of saving was
less but highly beneficial for mass production of paving blocks. The shaving would be more
if the sand availability is at greater distance like hilly area. This also reduces the burden of
dumping crusher dust on earth and hence environmental pollution.