Sunday, October 11, 2009

Laying of concrete-Kerala practices

Having worked with many workers in different work sites in Kerala,I can tell you one fact which is common among all these workers.They give only lip service to quality of work.
When you ask them about quality of work,all of them tell that they are not like others and they do the work in the correct manner irrespective of supervision or lack of supervision.But this is  just a  hollow promise,without any intension of following it up with action.In reality they will do only that which has less physical strain and they will try to make the owner of building believe that what they are doing is the correct manner of doing work.
While laying concrete usual follies or mistakes done by workers are the following
1.They add more water to the concrete so that it is easier for them to level the concrete or compact it in case of beams and columns even though more water in excess of allowed quantity will reduce strength of concrete.
2.They reduce quantity of coarse aggregates(3/4 inch metal if I use usual terminology) so that it will be easy for compaction especially when compaction is done manually without use of vibrator.They increase quantity of fine aggregates like river sand,again for less physical strain in mixing and compacting.
3.Cement quantity will be reduced only if material supply is also being arranged by the contractor.Otherwise cement will not be reduced as it is not affecting physical strain of concrete mixing and laying.
4.For beams and columns they talk as if concrete with more water is essential.After hearing it for some time any one will start thinking that columns and beams require concrete with more water.
As majority of houses and other buildings in Kerala are being constructed without professional guidance and supervision,there is also absolutely no structural design by a qualified Engineer forconcrete parts of these buildings.
Workers will lay steel as they feel comfortable so that steel tying and fixing can be the minimum possible to reduce steel work.
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I will tell you about two events among my varied experiences in dealing with unrelenting work force in concrete work.
We were laying concrete somewhere near Angamaly for a convent building.Suddenly mother superior of that convent wanted me to meet her.I went and met her
“Why are you concreting without sufficient water in concrete?”She asked.In fact I literally had to fight with unrelenting workers to reduce water in concrete to desired level and now this lady is finding fault with me for that.See how these workers have misinformed general public to believe that the follies narrated by them are correct.
At Ranny at the time of first roof slab concreting my client has called a few of the local contractors of building work who were quite unhappy for not getting work of this house as my client has chosen to get me for the work from far away Cochin.He called them to be present at the time of concrete to check whether the Engineer from Cochin and his workers are doing the concrete properly.After the tea within half an hour of commencement of concrete laying all of them left the place saying that ” now he will do it correctly as we have come”
I asked my client-“What do they say about steel reinforcement work for roof concrete?”
He replied-“They say that you have put steel for four houses in this roof”
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I have put steel only sufficient and essential for the work.Of course this sufficient and essential is four times according to worker as more steel means more work for him.As the work is taken up on square feet rate basis more steel work means lesser profit for him as the labour wages will increase due to more steel work.

Who is bothered about structural stability of the house?The concreted roof should not fall down immediately after removal of supports after curing period.Whatever happens later,the worker will not be around to face it.Even if he is locally available,he will wash his hands saying “You gave the work to me knowing very well that I am not an engineer?If you were so particular about stability of the house,you should have engaged an Engineer for the work”
At the time of negotiating to get contract for the building if you ask him “Should we not go for an Engineer to design and supervise the work?”
He will reply like this-“Why you have to waste money on an Engineer?I have built hundreds of houses without any Engineer.Nothing happened to any of the buildings.If you have more money to waste,get an Engineer'”
Concrete mixing practices are different in different parts of Kerala.
In Nilambur they use a sloping wooden case where they keep cement and aggregates at top side and as these are brought down mixed with water using hand tools,concrete mixed is received at end of sloping wooden case
At Alwaye they  use long spade to mix concrete.This make movement of spade and mixing easier.
At Cochin and many other places there is a bad habit of dumping aggregates one above other and trying to pour water and mixing whatever is available at one end.This practice prevents proper mixing of concrete.But here again who bothers?
Worker will vouch vehemently to the owner who does not know anything about concrete mixing that what he does is the correct and most appropriate method
Many people think that by using a manually operated mixer machine concrete is mixed properly.First of all workers will not put aggregates in proper proportion to reduce their strain in levelling and compacting concrete.Secondly the operator of mixer machine will not turn it sufficiently for proper mixing as he want the work to be over faster ,mixing or no mixing.
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The best way out in recent time available in major towns like Cochin are ready mix concrete.As the mixing and laying is done mostly by machine without much man power involvement,worker introduced excuses for low quality work will not come into play.Only precaution required is that ready mix supplier should be given instructions about quantity of water as they will again try to increase water content for easier pumping of concrete.
Vibrator is the best option for proper compaction of concrete after laying on roof or beams.The old method of using hand compaction with steel bars is likely to be affected by worker laziness and fatigue.
Another advantage of using ready mix concreting is that you can avoid too many workers running around roof to be concreted with all sorts of confusion and shouting at the time of concreting.In some places there is a practice of giving continuous run of  food and drink to these concrete workers including liquor to make them happy  for doing a lousy  irresponsible job for concreting roof of your house to be built only once in your life time
Another important aspect to be noted is curing required after concrete laying.Many worker turned contractors will advise house owner that spraying water once or twice is sufficient  again to reduce his labour charges.
Concrete laid will have to be kept under water for minimum two weeks.In case of slope roof,jute bags will have to be kept above slope roof with frequent spraying of water on it to keep concrete surface wet and cool.
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