COMMENTS

 Not an expert in civil engineering but the way construction is being done in general doesnt inspire me with confidence. I can visibly notice the professionalism in safety, quality of tools and equipment vastly inferior from the rest of the world. Just heard about this now confirming my fears. We are turning this out to be some massive pre BC pyramid of egypt with lives being lost and all that. The ease with which complex structures are being built around the world, these incidents shows our civil engineers in primitive light. We can clearly see that in the state of our infrastructure. At the same time we wont mature if we dont get our act together and build these things oursleves. Sridharan was clear when he said we dont have such massive engineering experience in India and we have to get our local companies exposure to international scale projects. 

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Not an expert but to help you  and having used the method of wrapping jute bags/ and also dry rolled paddy ropes for keeping the pillars/fresh concrete structures like flooring, masonry covered walls etc., wet for curing purpose for their becoming harder and more durable and also to give you a technical background,  the following is

From Wikipedia, the free encyclopedia

1930s vibrated concrete, manufactured in Croydon and installed by the LMS railway after an art deco refurbishment in Meols, United Kingdom.

Concrete plant facility (background) with concrete delivery trucks.

Concrete is a construction material composed of cement (commonly Portland cement) as well as other cementitious materials such as fly ash and slag cement, aggregate (generally a coarse aggregate such as gravel, limestone, or granite, plus a fine aggregate such as sand), water, and chemical admixtures. The word concrete comes from the Latin word "concretus" (meaning compact or condensed), the past participle of "concresco", from "com-" (together) and "cresco" (to grow).

Concrete solidifies and hardens after mixing with water and placement due to a chemical process known as hydration. The water reacts with the cement, which bonds the other components together, eventually creating a stone-like material. Concrete is used to make pavements, architectural structures, foundations, motorways/roads, bridges/overpasses, parking structures, brick/block walls and footings for gates, fences and poles.

- Vasanth Mysoremath

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Yes - it is common procedure to use gunny sacks soaked in water or curing compound to cure the concrete or tie the sack and pour water on it. Curing compounds may be sprayed directly on concrete but are not as effective as leaving wet gunny sacks in place for a longer time.

idontspam - different people (engineer, contractor, safety official) are responsible for different aspects of the project. The reinforcement splaying out may be because of pouring concrete from a greater height or not forming it correctly and so on. Without knowing all the facts, it is probably not right to blame one particular person or entity.

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Okay, so I understand that moisture is important for curing.  For the concrete, the loss of moisture is from the surface, so applying a barrier that can retain moisture and compensate for the evaposrative loss is what is being tried.

What I am wondering is  - how repeatable is the process of this gunny wrapping and human wetting using very elementary tools?  If I am using a plastic bottle to splash water on gunny sack around a big pillar... what are the chances that I will not get it (a) uniformly wet (b) Sufficiently wet such that it remains wet until the next round of wetting.

This seems to be more like the way our maid does the dishes.  Every once in a while, something gets left behind.  While washing the vessel once again is easily done, a weak spot in a concrete pillar is weak for life, is it not.

Can folks comment on: (a) Is this the international practise to wet concrete (b) Have there been studies on how effective this method is?

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 Without knowing all the facts, it is probably not right to blame one particular person or entity.

Please read my comment again. I have passed judgement based on the visual observation on the variety and primitiveness of tools and equipment used and practices in construction of some of the infrastructure projects. The accident in question may or may not have arisen due to the the tools and practices but the collapse supports the argument that something is definitely wrong if this must have happened. The primitivemess of some of the practices and tools a worker is equipped with in construction sites is clearly visible in comparision with similar labourers elsewhere in the developed world. My judgement also stems from the observation of the kind of engineering infrastructure we witness starting from the practice of laying streets, pavements, primitiveness of traffic markers etc. My argument is also not about curing technique of one pillar in the question. It is broader and I hope the point is appreciated in such a light.

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