Observing the process of wet concrete turning into a solid is, in fact, a waiting game that calls for patience and accuracy. Oftentimes, clients are observed in a rush to begin construction work, such as building walls or parking vehicles over a newly laid concrete surface. However, this can result in a weak construction in the future due to a lack of understanding of when to put load on the concrete. If youâre unsure about timelines or best practices, consulting with concrete suppliers in Oklahoma City such as Billâs Custom Concrete can provide valuable local expertise!Â
Initial Set vs. Final Set
The process from liquid mix to solid form takes place in steps. The first setting begins when the concrete starts becoming less plastic or stiffens. Such a stage takes a matter of hours after mixing, depending on the prevailing atmospheric conditions. At this point, you would not want to walk on it or put any other thing on top of it because you would end up creating permanent impressions. When can loads be placed on a concrete structure? Itâs crucial to remember that patience during these early hours sets the stage for long-term strength.
The final set will come later, anywhere from four to ten hours after pouring. Once the final set is attained, the concrete will be hard enough to withstand its own weight and light foot traffic without leaving imprints. But don’t be fooled by this hardness. Concrete is ready to withstand heavy machinery, automobiles, and construction traffic not when it is hard to the touch, because the chemical reactions involved in making it strong have barely begun.
The Critical 28-Day Period for Curing
When it comes to construction, the magic number is always 28 days. Concrete doesn’t actually “dry,” it “cures.” And this takes a chemical reaction, where all of the strength is achieved in this first month.
Concrete takes seven days to attain approximately 70 percent capacity strength. At this stage, light vehicles/machines may be safely placed, but heavy static load-bearing structures can pose a danger. It is essential to evaluate the potential load on the structure during this period to avoid compromising the integrity of the concrete. It is widely assumed that concrete attains complete design strength at the end of 28 days. At this stage, engineers can confidently load the structure with its maximum load.
Factors Affecting the Timeline
Although the standard curing time in the industry is 28 days, in most cases, this is affected by varying circumstances. One such factor where a massive impact can be noted is in relation to temperatures. When it is hot, evaporation of water takes place quickly; this can be a problem if it is not kept saturated because hydration will cease before it is supposed to.
The level of humidity is another factor which greatly matters in this case. A humid atmosphere assists in increasing the strength of concrete, but a dry atmosphere with winds can cause a crack in the concrete surface. Apart from this, the mix designs have different effects on curing time. While some mix designs have accelerators to fast-track curing, others have retarders.
Trust Your Concrete Contractors
Every pour is different. While some guidelines are good, no substitute exists for experience in making these decisions. We are attuned to local weather, soils, and the exact chemical composition of your mix delivered on our projects. Additionally, strength tests can be performed before approving heavy loads.
Disregarding expert advice when it comes to accelerating construction projects can be a poor choice. Loading your structure too early can cause you to end up with micro-cracking, which may weaken your steel reinforcement, making it collapse in the future. It’s especially important to avoid placing a concentrated load on a concrete slab before the concrete has reached its full strength, as this can lead to structural damage that may go unnoticed until much later.
Providing Long-Term Durability
Waiting out the curing time is, without a doubt, the very best investment you can make in your buildingâs future. By taking the time to understand and follow the rules of initial set versus full strength, and taking into consideration the 28-day rule, you will have a structure that will last a lifetime. Prior to subjecting a new pour of concrete to heavy loads, it’s always wise to check with the pros at Billâs Custom Concrete!
