Water to Concrete: Friends or Foes?

Water to Concrete: friends or foes?

How does rain and moisture affect structures and building made with concrete?

Water is an important component of concrete. Water is essential for the proper curing and binding of cement and aggregates to form concrete. It is estimated that around 14 to 21% of concrete is water. However, after the mixture has hardened, water can act as a deleterious substance to concrete structures. 

Alkali-silica reaction gel (ASR) is one type of concrete cancer worsened by excessive moisture in already hardened cement. The expansion and swelling of ASR could lead to the formation of cracks that would contribute to further deterioration of concrete. Sweating slab syndrome is also an effect of uncontrolled humidity which can pose a great risk to people working inside buildings.

How to prevent water damage in concrete?

Engineers advice the following measures to control excessive moisture from damaging concrete structures:

1. Proper ventilation

2. Using protective layers and finishing such as epoxies, rubber paints, and waterproofing membranes

3. Periodic assessment of cracks and other crevices where moisture could seep in

Pouring of concrete is also not advised when it's raining. Rain can wash away cement particles that can compromise the strength of the concrete. It can also increase the tendency of concrete to scale and dust over time. These are forms of damages that are difficult to solve even if the concrete is new and recently cured.