As the concrete hardens, caused by the cement and water forming bonds, some water escapes through evaporation. This reduces the size of the concrete slab, and since concrete is a tough, tightly bound substance, this material loss creates stress. This stress can lead to cracks in the concrete.
Why Does Concrete Crack?
Cracking in concrete is an unavoidable phenomenon. Even though concrete is one of the most durable and reliable construction materials, it is also prone to cracking for various reasons. To understand why concrete cracks, it is essential to understand the properties of concrete and the forces that can cause damage to form.
Concrete is a composite material of cement, water, sand, and aggregates like gravel and stones. When mixed together, these materials form a paste that hardens to form a solid mass. As concrete dries and cures, it shrinks due to the evaporation of moisture and the chemical reaction of cement and water. This shrinkage is the primary cause of cracking in concrete and is more pronounced in large slabs or walls due to the larger surface area.
In addition to shrinkage, other external forces can cause concrete to crack. Temperature changes can cause thermal stress and cracking, as can the ground settlement beneath the concrete slab. Poor construction practices can also contribute to cracking, such as using too much water during mixing or not allowing for adequate curing time.
The best way to prevent cracking in concrete is to use good construction practices. This includes using the right mix of materials, allowing for adequate curing and drying time,