In general, wet concrete is workable for about 1-2 hours. After that, the material will begin to stiffen and will eventually become too hard to work with. However, there are a few factors that can affect this timeline. For instance, if the weather is hot and humid, the concrete will set more quickly. Similarly, if the concrete is mixed with a accelerating admixture, it will also set more quickly. As a result, it is important to be aware of these factors when working with wet concrete.