Cementing in cold conditions

[Garry]

Erm Soz .. whilst moving this topic I manage to nuke it :oops: can anyone remember the gist of it ?

[Kev]

Re: Cementing in cold conditions

Hehe .. yea dont do it .. wtf happened to the topic then ? thought you were in control there boss :roll:

[Dan]

Re: Cementing in cold conditions

Hehe....... Ross county lost the big game that night

[gardener12]

Re: Cementing in cold conditions

That wasnt the same night ..he just made an arse of it :D

[Muz]

Here ya go .. more about concreting but useful all the same



Q: What precautions do I have to take during cold-weather concreting?

I am a contractor involved with a variety of concrete projects including commercial buildings, residential foundations and flatwork, as well as pavement and curb and gutter. The projects are located in a northern climate. I must ensure that provisions taken for cold weather conditions follow acceptable industry practice to assure a quality finished product. When should I be concerned about cold weather placement conditions and what practices should be used to achieve quality results?


A: Cold weather concreting is a common and necessary practice, and every cold weather application must be considered carefully to accommodate its unique requirements. The current American Concrete Institute definition of cold-weather concreting, as stated in ACI 306 is, “a period when for more than 3 successive days the average daily air temperature drops below 5°C (40°F) and stays below 10°C (50°F) for more than one-half of any 24 hour period.” This definition can potentially lead to problems with freezing at early age of the concrete.


Rule number ONE is that ALL concrete must be protected from freezing until it has reached a minimum strength of 3.5 MPa (500 psi), which typically happens within the first 24 hours. In addition, whenever air temperature at the time of concrete placement is below 5°C (40°F) and freezing temperatures within the first 24 hours after placement are expected, the following general issues should be considered:
(1) Adjustment of construction schedule regarding loads imposed on the new concrete structure.
(2) Placing and curing temperatures to produce quality concrete.
The exposure of concrete to cold weather will extend the time required for it to gain strength. In structures that will carry large loads at an early age, concrete must be maintained at a minimum of 10°C (50°F) to accommodate stripping of forms and shoring and to permit loading of the structure. In many cases, achieving the required durability will require a protection period of more than 24 hours. This may not be an issue with residential applications where applied loads are typically small and may be applied in small increments over several days or weeks. In no case should concrete be allowed to freeze during the first 24 hours after it has been placed. Since cement hydration is an exothermic reaction, the concrete mixture produces some heat on its own. Protecting that heat from escaping the system may be all that is required for good concrete quality, while more severe temperatures may require supplemental heat.

[FnDaily]

Fek dat geezas .. I'd be inside wid a cuppa