Light Weight Concrete
Light Weight Concrete
Light Weight Concrete
On
V.S.C.MOURYA
(Y7CE226)
INTRODUCTION:
Light weight concrete (LCM) is the one which has less weight than the normal
ordinary concrete. It has density of 300 to 2000 kg/m3. It can be prepared at the site as
ordinary concrete but the coarse aggregate or fine aggregate is replaced by light weight
materials. Light weight concrete may be prepared by the replacement of coarse aggregate
by oil palm shell or with foam or pumice aggregate etc. Or fine aggregate is replaced by
fly ash or rice husk ash etc. The following table represents the replaceable materials with
their density in lb/Cu.ft.
Table 1 Aggregates with their density
1. Ops concrete
2. Foam concrete
3. Structural light weight concrete
OPS CONCRETE:
OPS is hard in nature and does not deteriorate easily once bound in concrete and
therefore, it does not contaminate or leach to produce toxic substances. The bulk density
of OPS is about 500 to 600 kg/m3, producing concretes of about 1900 kg/m3 in density,
which makes them lightweight. OPS to be used as coarse aggregate in the production of
structural lightweight concrete especially for the construction of low cost houses.
OPS concrete beams showed good ductility behavior. The crack widths at service
loads ranged between 0.22 mm to 0.27 mm and this was within the maximum allowable
value as stipulated by BS 8110 for durability requirements. It has been found that OPS
concrete easily attains the strength of more than 17 MPa, which is a requirement for
structural lightweight concrete as per ASTM C330.
FOAM CONCRETE:
It is the concrete having mortar and foam instead of the Coarse aggregate. It has
the tendency of the free flowing due to absence of the coarse aggregate. This foam has no
chemical action in concrete. It only serves as a temporary wrapping material for the air
bubbles till cement mortar develops its own final set and strength. Hydrolysated protein
base is mix and mash into a concentrated liquid call LCM Foaming agent is used to make
the foam.
The high stability of LCM Foam prevents a loss of volume during mixing,
conveying (even pumping), pouring or during hardening process. The use of appropriate
mould release agent has substantial influence on the surface finish of face cast against the
mould. The curing of this concrete is as normal as it can be.
The entrained air with help of foam reduces density of concrete. The density would
naturally depend on the extent of foam injected in the slurry. Foaming Generator enables
accurate dozing of foam, thereby enabling production of wide range of controlled
densities from 300 kg/cu.m to 1,800 kg/cu.m. The water absorption of LCM is also very
low. It is in the range of 6.5% to 14% depending on the density.
USES OF THE FOAM CONCRETE:
Coarse or fine aggregate are replaced with light weight materials based on the
required density of concrete.
Beams with OPS is tested and results were given. It shows acceptable strength.
www.nrmca.org/aboutconcrete/cips/36p.pdf
www.greenhomebuilding.com/pumicecrete.htm
www.ebrindia.com/