MODERN HOUSE CONSTRUCTION TECHNOLOGY
Introduction: Using small bricks for house construction takes more time and skill of the workers. Now the new technology of using hollow concrete blocks can make house construction quite easy and also speed up the construction. The preformed concrete blocks can be easily formed at site and used in the boundary walls, room walls. The hollow bricks are stronger than the bricks and also light weight.
Construction: The hollow concrete blocks can be formed with the help of a mold in manual or with machine. The blocks can be formed in various sizes such as 4” thick or 8”/9” thick. As per IS2185-2005, the standard sizes are 100x200x400, 200x200x400, 250x200x400 although different sizes can be made based on mutual agreement between the user and supplier as per requirement.
The cost-benefit analysis: The cost of the hollow concrete blocks as a unit to replace number of bricks is same or slightly lower than the bricks but the main benefits are the reduced heating and air-conditioning load by almost 50% as has been demonstrated by project claimers. The strength of the structure to bear the earthquake is also higher due to being interlocked. The main saving of the cost is in the mortar cost, labor and time cost which can be as low as 10% of the original cost depending on the size of the blocks. Overall saving is estimated to 40% in the construction of a large building when the raw material is directly sourced and blocks are made at site to avoid multiple handling of blocks.
Special precautions: for electrification purpose horizontal opening within the blocks should be utilized although vertical grooving can be made without damaging the strength of structure.
Step 1- applying cement solution at top of block, step 2- fixing the block at right position to form the wall.
Step-3-Corner columns can be constructed by providing reinforcement in the column and putting the corner blocks one above other and filling with the concrete. The benefit with this arrangement shall be that there is no waiting period for curing and construction can continue at the same speed.
Calculation of cost of the blocks:
Overall size of blocks= 9”x18”x9”= 228x457x228 mm
Volume of a block= 0.024m3 minus hollow portion=0.0026 m3
So concrete volume= 0.0214m3 with ration 1:3:5, Cement=0.00238m3, coarse sand 0.00714m3, chips 0.0119m3
Cost- cement- density-3000kg/m3= 7.14kg @ Rs.6= Rs.42.84/-
Sand- density 1500kg/m3=10.71kg, cost @ Rs.1413/m3= Rs.10.08/-
Chips- density-1200kg /m3=14.28kg, cost 2402/ m3= Rs.28.58/-
Total weight of block= 32.03 kg, total cost of material = Rs.81.50/-
One block replaces to 12 bricks, so per brick material cost – Rs.6.80/-, labor cost Rs.0.70/- net Rs. 7.50
Labor Cost of making one block = Rs.8/-, per day out put= 150 blocks by 3 persons, daily wage Rs.400/-
Real saving in building construction- construction time reduced by 1/10., plus mortar reduced by 1/10. A floor construction can be raised in just three days. A cost saving of almost Rs.500/- per sq ft of labor.
So for a 200sqft room, the saving works out to be Rs.1,00,000/-.
Savings on plaster, material + labor- Rs.50,000/-
Savings on making extra columns, etc. – Rs.50,000/-
Total savings per room of 200 Sqft- Rs.2,00,000/-