Concrete slabs are meant to carry traffic, but they must gain sufficient strength first. How long does it take to gain this strength, and what could you do to speed up the process?
When Can You Walk on Concrete?
Generally, concrete will within 4 to 6 hours. You can walk on concrete after 6 hours provided you are wearing a flat bottom footwear such as a concrete finishing shoes.
How quickly you can walk on concrete after casting depends on various factors, including the mix design, slab thickness, and prevailing weather conditions. Once the concrete has cured sufficiently to carry a person’s weight, you can walk on it.
Fresh concrete slabs require shrinkage joints to be cut within 6 to 24 hours after casting. This means that the concrete can bear the weight of the concrete saw and operator. However, it will probably not withstand point loads, such as pet claws, spiked or high-heeled shoes, car tracks, or any other weight.
For this reason, it’s best to wait at least 24 hours before walking on freshly cast concrete, but preferably 48 hours. You should wait even longer if the weather is cold or the slab is thick.
You dog can probably walk on concrete after 12 hours. However, to be safe, I recommend you let the dog walk on fresh concrete only after 24 to 48 hours (2 days).
How Long Should Concrete Cure Before Putting Weight on It?
Concrete generally reaches final set within 24 to 48 hours after casting. This number may vary significantly, depending on a host of factors, mainly the mix design, ambient conditions, and how well the concrete is protected.
Then, there’s the question of the weight: what type of weight are you placing on the concrete? Is it a power float and the person operating it, as would be the case in flooring concrete? This strength gain level would correlate with initial set, which could be as little as 4 hours after casting.
You should naturally keep larger weights away until the concrete reaches final set, at least. Concrete reaches its design strength (known as full strength) after 28 days of curing. For this reason, it is usually prudent to wait until that point to place considerable weight on the concrete.
A good rule is to wait at least 24 hours before allowing foot traffic on newly placed pavement concrete and ten days before driving on a newly placed driveway.
Keep in mind that concrete never stops curing and thus never stops gaining strength. However, the rate of strength gain decreases dramatically after 28 days.
How Long Should I Wait to Put Furniture on New Concrete?
Furniture tends to exert point loads on concrete, which could damage your newly cast floors.
Standard practice dictates waiting at least ten days before putting the concrete to heavy use. This includes placing furniture on the floor.
Concrete will gain enough strength to park a car after 7 to 10 days.
Wait for four weeks (28 days) before you can park or drive heavy vehicles such as large trucks.