Concrete tips


How temperature affects curing times

Experts agree that ideally concrete should cure for 7 days at temperatures between 65-85°F under 100% humidity. However, even the most conscientious builder knows this is simply not possible in most cases.

What can maturity testing do to help improve concrete quality in non-ideal climates? Because maturity testing also tracks temperature history during the critical early-age curing process, it is often possible to take valuable steps to improve the cure before problems develop. For example, heat can be applied when it is shown that the concrete is getting too cold, thus ensuring completion of the hydration reaction needed for proper strength gain. Conversely, it has been proven that adding too much heat is detrimental to long-term durability and can lead to lower ultimate strengths, so taking steps to prevent overheating is also beneficial. Plus, if the contractor can avoid adding heat when it's not necessary, the savings add up very quickly.

COLD WEATHER APPLICATIONS

HOT WEATHER APPLICATIONS

Do you need to accelerate the curing process in the dead of winter? Using maturity testing will give you a clear idea of just how much heat you will need to add to obtain the needed strength in the shortest time possible.

Concrete gives off heat as it cures, and often a satisfactory cure can be obtained merely by covering the slab or wall with an insulating blanket. Also, covering keeps needed moisture in - particularly helpful in cold, dry climates.

In many cases, contractors can save a tremendous amount of money simply by turning off external heaters once the maturity system shows it's not necessary. One contractor reported saving more than $5000 in one weekend because he knew the structure had obtained sufficient strength.

Some mixes can tolerate heat better than others. With maturity testing, one can monitor the performance of concrete cured at high temperatures to ensure sufficient strength. For example, some high-early strength mixes cure very well at high temperatures (sometimes as high as 170° F!).

Curing the initial lab cylinders at high temperature (as tracked by the maturity meter) will give a clear picture of the actual performance under high temperature field conditions, and can identify potential problems before the job starts.