Late Setting of Concrete

[concreteworld]

Dear All

Please see attached photos of late setting of concrete (concrete in one pour line did not set up to 70 Hrs after pouring). The structure is a water-tank wall and we as the Supervising Consultant of the project instructed the contractor to continue curing with hessian cloth covered for another 24 hours.

In case the concrete still doesn't set after 70+24 = 94 Hrs (almost 4 days), what measures can be taken to rectify the situation? Photos show that one truck may have extra chemical dosage. Above concrete is fully set. Concrete in some part of the affected area can be removed by hand.

How long we can advise the contractor to leave the concrete to cure until set? If doesnot set after 5-6 days what repair actions can be taken to provide a water-tight wall?

Thanks in advance

 

[concreteworld]

second pic..

 

[concreteworld]

another photo..

 

[concretemasonry]

What is the mix design for the concrete, the controls over batching and the on-site sampling of the mix, inspection and supervision that were done prior to placing the concrete? I assume there are no compression test run yet to determine the hydration of the delivered mix.

On site dosing of admixtures is usually not a good thing unless approved by an inspector.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[BigH]

How much retarder was used? If overdosed, we have had experience similar. Ours was mass concrete placement and we simply removed the bad areas and replaced.