The of absorption is 0.5 to 2 %

The bulk specific gravity of LWA is varies with
particles size of aggregate. The specific gravity is higher for the fine
aggregate and lower for the coarse aggregate. The loose and dry bulk density
for the lightweight coarse aggregate and lightweight fine aggregate are shown
in Figure 2.3. As for the typical natural or normal aggregate, the bulk density
is about 1400kg/m3 to 1600kg/m3 ( Lydon , 1972 )2.4.2    Specific
GravityThe most lightly coarse aggregate has a specific
gravity of 0.5 to 0.6. Generally, the specific gravity of the lightweight
coarse aggregate is ranging from 1.2 to 1.5 whereas for the fine aggregate, the
specific gravity is 1.3 to 1.7. However, the specific gravity also highly
depends on the grading of aggregate. The density is increasing with the
decreasing of the particles size of aggregate. 2.4.3    Moisture
Content and Water AbsorptionIn general, LWA have significantly higher value of
water absorption than the normal aggregate due to the cellular structure . The water absorption of and the rate of absorption is
depends on:·        
Type and the
particle size of aggregatesThe absorption rate of LWA is vary which starting from
being fairly slow, continuing at a steady constant rate for long period, then
being rapidly increasing , and finally followed by more slower constant rate
for a long period ·        
The pore volume
and distribution of pore between particleThe structure of pore is whether connected or
disconnected. The early absorption of LWA   is ranges from 5% to 15 % of dry weight of
concrete after 24 hours according to standard ASTM C127 (1999). Whereas for the
normal aggregate, the rate of absorption is 0.5 to 2 % after 24 hours
absorption ( Lydon, 1972 ). Thus, from the typical data obtained through the
previous test that have been done , the absorption rate of NWA is usually less
than 2 % which is much lower than LWA.2.4.4    Aggregate
SizeThe use of larger maximum size of aggregate affects
the strength in several ways. ·        
Larger aggregates
have less specific surface area and the aggregate paste bond strength,
aggregate fails along surfaces of aggregates resulting in reduced compressive
strength of concrete. ·        
Larger aggregate
results in a smaller volume of paste which provide more restraint to volume
changes of the paste in a given volume. This may induce additional stresses in
the paste, creating microcracks prior to application of load, which may be a
critical factor in very high strength concretes (Neville A.M.2000). Therefore, it is the general consensus that smaller
size aggregates should be used to produce higher strength concrete.  2.4.5    Shape
and Surface TextureParticle shape and surface texture influence the
properties of freshly mixed concrete more than the properties of hardened
concrete. Rough-textured, angular, and elongated particles require more water
to produce workable concrete than smooth, rounded and compact aggregate
(Clarke, J.L., 2005). Consequently, the cement content must also be
increased to maintain the water-cement ratio. Generally, flat and elongated
particles are avoided or are limited to about 15% by the total weight of aggregate.
The essential requirement of an aggregate for concrete production is it remains
stable within the concrete and in the particular environment throughout the
design life of the concrete without adversely affecting the performance of
concrete in either the fresh or hardened state. Rougher texture results in a greater adhesion or bond
between the particles and cement matrix. Determination of the quality of bond
is rather difficult. When bond is good, a crushed concrete specimen should
contain some aggregate particles broken right through, in addition to the more
numerous ones separated from the paste matrix. On the other hand, an excess of
fractured particles suggest that the aggregate is too weak. 2.4.5    Bonding
PropertiesThe bond between the LWA and the surrounding hydrated
paste in the mix is considered as good, thus making it to offer an advantage in
term of its bonding properties. The factors that contribute to the good bonding
properties is due to the rough surface textures of the LWA. The rough surface
textures of the LWA are favorable to fine mechanical interlocking that exist
between the aggregate and cement paste. The high porosity of the LWA also
contributes to some penetration of the cement paste into the opening of the
free surface pores in the aggregate particles. 2.5       Classification
of Wastes

According to Chandra (1997), waste is defined as the
unused discharge residues which generated from variety of activities and the
radioactive industrial waste is separated. The waste can be classified into
industrial waste, residential and business wastes. The separation of the wastes
is convenience for the purpose of treatment and recycling. 

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