The purpose of curing is to reduce the rate of heat loss of freshly placed concrete to the atmosphere and to minimize the temperature gradient across concrete cross section, So why don't recommend curing by ponding and polythene sheets?
Standard curing of concrete at water but polythine sheet can also be used but with reduction in compressive strength comparing with standard curing . Some paper discuss the effect of use polythine sheet on comp. Strength
Thanks Rana Burhan Alshahwany ... for your answer,...
can you suggest reference paper for me...?
COMPARISON OF DIFFERENT CURING EFFECTS ON
CONCRETE STRENGTH
M. Naderi1
, R. Sheibani2
, and M. A. Shayanfar3
1
Associate. Prof., Imam Khomeini International University, Head of Civil. Eng. Dept., Takestan Azad
University, Iran 2
P. G. Student, Civil Eng. Dept. Takestan Azad University, Iran 3
School of Civil Engineering, Iran University of Science and Technology, Teh
Ponding: This method of thermal curing is readily affected by weather condition (cold wind). Moreover, a large amount of water used has to be disposed off the construction sites after curing.
Polythene sheet: This method of curing is based on the principle that there is no flow of air over the concrete surface and thereby no evaporation can take place on top of the freshly concreted surface by provision of polythene sheets. However, it suffers from the demerit that polythene sheets can be easily blown off in windy condition and the performance of curing would be affected. Moreover, for water lost due to self-desiccation, this method cannot replenish these losses.
Ponding is a quick, inexpensive and effective form of curing when there is a ready supply of good ‘dam’ material (eg clay soil), a supply of water, and the ‘pond’ does not interfere with subsequent building operations. It has the added advantage of helping to maintain a uniform temperature on the surface of the slab. There is thus less likelihood of early age thermal cracking in slabs that are cured by water ponding
Thanks Rana Burhan Alshahwany .. for your answer.. I really appreciate ..
All concrete curing processes need supervision. Ponding guarantees there will be enough curing water for setting but it's messy, obstructive and lengthy. Curing with impermeable sheets or with sprayed curing forming films can be practical.
What I used in University of Warwick (Structural Lab): the casted concrete (after 12 to 24 hours) is covered by damped hessian and polythene sheets, and cured for 7 days. In 2016, I casted 9x1.25x0.15 m concrete slab, and this was the procedure.
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