Wednesday 30 November 2016

How To Construct Concrete Floor Without Granite -Osaz’ ENOBAKHARE

Building Construction
with Cellular Concrete
Surprised? Not as much as Trump’s victory. The technology has been with us in a while but it probably wasn’t as appealing. Cellular concrete is made from a combination of slurry of cement, fly ash, sand and water mixed together to form ‘concrete’ molds. Back here, contractors are beginning to appreciate the use of cellular concrete because it has light weight, making it easy to work with as well as the fact that it is very durable, highly water resistant and relatively inexpensive when compared to the regular concrete.

Interestingly, although it is light in weight, cellular concrete is very strong and hard as the regular concrete when it sets. Before now, it’s uses were restricted to making of ‘concrete’ blocks and as an infill material in wall panels for buildings, also in the filling of voids and port-holes on bad roads but today advancement in the technology has made it suitable for the construction of select structural members (e.g. partially-loaded columns and beams, and for suspended and ground floors with fair loading requirements) in buildings. 
It can be used for all structural members in residential apartments, especially private residences. It has also being successfully used in the construction of estate roads or less-traffic roads, public drainages, inspection chambers, piers, copings, manholes, swimming pools, fountains, hoardings, etc.

When using cellular concrete it is important to note that the mix ratio is quite different from that of regular concrete even though the method of application remains the same. Cellular concrete is also referred to as light-weight concrete or foam concrete or foamed cement.

L-R Cellular Concrete used in the construction 
of 
Drainage, Floor and Swimming Pool in Nigeria
This is a caveat; if you intend to use cellular concrete and your structural drawings specifies the use of the regular concrete (as usual), it is important that you ask your Structural Engineer to do a re-design so that the accurate mix ratio for the convenient use of cellular concrete is specified. Don’t worry about the cost of redesign, it very inconsequential relative to the cost you will save using cellular concrete. Although using cellular concrete has been proven to reduce the cost of construction by a whopping 20%, building with it on a ‘guess’ basis is not safe because its technical specifications are quite different.


Building with Cellular Concrete Blocks
Generally, cellular concrete have higher tensile, flexural and compressive strength than the regular concrete. It also has a better adhesion to surfaces. In using cellular concrete for load-bearing members, most contractors/engineers/builders prefer to mix the foamed cement with stone dust and sharp sand. This increases its density. The foamed cement comes with a polymerized liquid which is mixed with water to increase the bonding strength and damp-proofing property. 



Perimeter Fence built with Cellular Concrete
Because of its inherent tensile strength, cellular concrete requires lesser quantity and sizes of steel rebars. This makes it possible to use 10mm diameter steel rebar for suspended floors instead of 12mm.  At the moment, a cubic meter of regular concrete is often produced at the cost of 32,000 NGN – 40,000 NGN depending on the mix ratio, while cellular concrete of the same volume can be produced as low as 20,000 NGN.

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