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COLD WEATHER CONCRETING

COLD WEATHER CONCRETING

INTRODUCTION
The period developed when the mean day to day temperature falls below 40 C for more than three consecutive days is called cold weather and the concreting done in that period is referred to as cold weather concreting. However, special conditions are to be maintained when finishing, placing, curing, and protecting concrete from severe weather conditions. As during winter conditions can change abruptly, better planning in execution of the work is essential.

When concrete is in plastic state and it freezes, then strength reduces by 50% which in turn affects its durability and workability. Hence, it should be protected from freezing until it attains a minimum of 3.5 MPa.

When concrete is at low temperature, it affects greatly the setting time and rate of gain of strength due to hydration process being hindered. In this case, a thumb rule can be applied which indicates that a drop of temperature in concrete by 100 c will lead to increase in setting time of concrete by twice. This will affect the formwork removal time and will create a problem at construction site.

All these factors play a great role in cold weather concreting.

Freezing of concrete creating problems at site
Fig 1: Freezing of concrete creating problems at site
COURTESY: THE VIRGINIA READY MIXED CONCRETE ASSOCIATION

REMEDIES FOR COLD WEATHER CONCRETING
Some of the remedies are –

Cold weather concreting done at site
Fig 2: Cold weather concreting done at site
COURTESY: KUHLMAN COPERATION

CONCLUSION
During cold weather concreting, it becomes difficult to maintain the correct temperature required for curing and setting. All these preventive measures can help to a great extentbut care should be taken to control the temperature as much as possible. In extreme cases, the concreting can be stopped as quality is important. In such conditions, the construction equipment must work in rapid rate for continuous mixing so that concrete doesn’t freeze. Moreover, cements like rapid hardening can be used to remove formwork within a very small amount of time. It is highly recommended to use cements as per code standards so as to have durability, strength and required hydration in cement.

REFERENCES
• Portland Cement Associations, “What Happens When Concrete Freezes?”- https://www.cement.org/learn/concrete-technology/concrete-construction/cold-weather-concreting
• Nevada Ready Mix, “Cold Weather Concreting – What, Why and How?”- https://www.nevadareadymix.com/concrete-tips/cold-weather-concreting/
• ConcreteNetwork.com, “WHY IS COLD WEATHER A PROBLEM WHEN POURING CONCRETE?”- https://www.concretenetwork.com/cold-weather-concrete/weather.html
• Buildings Solution Group, “What factors are important during hot – and cold – weather concrete placement?”- https://builderssolutiongroup.blogspot.com/2014/04/what-factors-are-important-during-hot.html
• The balance small business, “Tips for Curing Concrete in Cold Weather”-
https://www.thebalancesmb.com/expert-tips-on-how-to-cure-concrete-in-cold-weather-845024

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Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

One comment on "COLD WEATHER CONCRETING"

Alia says:

Amazing explanation on this topic.

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