When it comes to the process of installing concrete and timing of concrete delivery, curing is considered one of the most vital steps. Curing increases the strength of concrete as well as its durability. Here is how it happens. Concrete becomes hard due to hydration. However, this process only occurs if there is water and if the temperature stays within the suitable range. The process of curing occurs between 5 to 7 days after placement. During this time the surface needs to be kept moist in order to allow the hydration to proceed.
Hot or Cold Temperature When Concrete Delivery Occurs
According to concrete delivery expert Aggregate Minnesota, extreme temperature changes make it challenging to correctly cure concrete. For instance, on hot days a lot of water is obviously lost due to evaporation. On the other hand, if the temperature drops near freezing, hydration stops. When these conditions are present, concrete stops gaining strength. As a rule, the temperature of concrete should not be allowed to fall below 10 degrees Celsius.
Air Entrained Concrete
These are actually air pockets that release internal pressure on the concrete by providing it with billions of microscopic air cells per cubic foot. These air pockets expand when the it freezes. This type of concrete is created using air-entraining Portland cement. The volume of air injected is somewhere between 4 and 7 percent depending on conditions.
In order to produce a properly cured concrete one must first mix the right proportions. Ready mix concrete delivery recommends the rule of 6, which goes like this:
- Minimum cement content of 6 bags per cubic yard of concrete
- 6 gallons of water per bag of cement
- Minimum of 6 days curing period
- If the concrete is going to be exposed to freezing and thawing, an air content level of 6%
When it comes to the curing process and timing of concrete delivery, the first three days are the most critical as the concrete is going to permanently set during this time frame. Aside from spraying the area in order to keep it moist, you can also use some plastic sheeting to provide some additional protection. For bigger jobs, a process called ponding the area is warranted. This is done by using barriers around the perimeter of the freshly laid concrete in order to hold a certain amount of water.