Concrete pouring in winter VS summer season

Temperature for pouring concrete in winter VS summer

 

Pouring concrete in summer or winter weather is no problem when you make sure the concrete temperature between between 40°F ~ 80°F. Because the concrete will make hydration reaction with water. If below 40°F ( the water will be freeze ) or over 80°F( the water evaporates quickly ), the water cannot deep into the concrete cement particles well. So the concrete hydrated will not be 100%. Of course, in hot weather or cold winter, adding admixture agent to concrete can also play a good role..

After pouring, you need to do concrete pump maintenance at first. The concrete maintenance is also very important. Otherwise, it will face concrete repair and waterproof work in the long time. 

Thus it is important to take the right steps to keep concrete temperature, and proper admixture for concrete retarding or early strength. Different concrete admixtures have different effects in hot weather and cold winter temperatures. When these jobs are sufficient, the construction quality can be guaranteed.

Concrete Pouring problem in hot temperature weather

 

Hot environment is not only including blazing weather, but also humidity and high wind included.

 

The hot temperature will lead to accelerated evaporation of water.

The concrete hydration is not sufficient.

Rheological property of concrete mixture  is low.

The setting time of concrete is fast.

 

If dont take proper admixture agent, the concrete strength and hardness will be fail and cracks will appear in the concrete. It will increase the burden of concrete repair in the future.

Tips for Pouring Concrete in Hot Weather

 

In hot weather, the poured concrete has the phenomenon of accelerated cure gel speed and reduced strength. Thus, the pouring should be started at low temperature in the morning and night, also add water reducing agent. The following measures should be taken into account.

 

  • Concrete mixing process in summer.
  • Transportation process in summer.
  • Pouring process in summer.
  • Maintenance process in summer.

Tips for Concrete Mixing in summer:

Add ice and cold water into mixing.

Increase the amount of fly ash, reduce the amount of cement, increase the particle size of aggregate and increase the slump if possible.

 

When mixing concrete in summer, adding water reducing and air entraining components, retarding components are needed, which will be adjust the setting time of concrete in hot weather. Polycarboxylic acid is an air entraining agent.

 

Entraining agent technical data

Water reduction rate Slump increase Air content Compressive strength ratio Impermeability label
>8% >9cm ≥4.2% 28D >100% ≥S20

Tips for Transportation:

Cover the geotextiles and sunshades to prevent external heat.

Tips for Summer Pouring:

Oil stain and construction waste shall be removed from the pouring area, and vibrators and other working equipment shall be prepared in advance to ensure rapid and continuous pouring.

Tips for Concrete Maintenance in Summer:

After pouring, cover the shelter and spray water regularly to ensure the surface is wet until the end of curing time. If the surface is not wet, it is easy to crack. Also Show warning signs nearby.

Concrete Pouring problem in cold temperature weather

When the temperature is below 40°F, the concrete will set for a long time, the hydration of the concrete will basically stop, and the concrete strength will not increase. Thus the construction building quality can not be guaranteed. Adding concrete admixtures can also avoid these problems.

 

Setting time of concrete is long.

Concrete hydration is stop.

Concrete frost crack.

 

Tips for Pouring Concrete in Cold Weather

 

In cold winter, if the concrete cannot be effectively hydrated, not only the concrete cannot be hardened and have good strength, but also affect project quality. The concrete pouring shall be started when the temperature begins to rise in the morning. Avoiding freezing during the initial concrete set. The following measures can be considered in mixing, transportation, pouring and maintenance to make sure concrete hydrated 100%.

 

Concrete Mixing in Winter.

Transportation in winter.

Pouring in winter.

Maintenance in winter.

Tips for Concrete Pouring in Cold temperature:

Remove snow from frameworks, make sure concrete rapid and continuous pouring.

Add EPS board at frameworks till concrete cured.

 

Tips for Concrete Maintenance in Winter:

Cover with plastic film for insulation, also the cover can reduce the evaporation of concrete moisture.

Extend the frameworks removal time.

 

Tips for Concrete Mixing in winter:

Before mixing, ensure that the raw materials are free of frozen blocks, add antifreeze, and use cement with high hydration heat.

 

Tips for Transportation in winter:

Cover the insulation layer to reduce heat loss.