Dampening of the subgrade or the wood concrete forms prior to placement of concrete wall should be done to

Dampening of the subgrade or the wood concrete forms prior to placement of concrete wall should be done to

• A. Cause a High Water / Cement Ratio And Greatly Reduce the Strength
• B. Promote Organic Growth And Should Be Avoided
• C. Prevent Rapid Extraction of the Mixing Water From the Concrete
• D. Cause an Excess of Surface Water to Appear After Floating

Answer: (C)

Dampening the subgrade or wood forms before placing concrete walls is about controlling how fast water leaves the fresh concrete. Fresh concrete needs water to hydrate properly, but if the surface is dry or very absorbent, it acts like a sponge and pulls water out of the mix too quickly. That suction can cause plastic shrinkage cracking, a weak or uneven surface, and poor bonding at the surface. Moistening the surface beforehand reduces that suction, helping retain the right amount of moisture near the surface, promoting better curing, a smoother finish, and a stronger, more uniform wall. It’s not about increasing the water-cement ratio, fostering organic growth, or leaving extra surface water after finishing.

Dampening the subgrade or wood forms before placing concrete walls is about controlling how fast water leaves the fresh concrete. Fresh concrete needs water to hydrate properly, but if the surface is dry or very absorbent, it acts like a sponge and pulls water out of the mix too quickly. That suction can cause plastic shrinkage cracking, a weak or uneven surface, and poor bonding at the surface.

Moistening the surface beforehand reduces that suction, helping retain the right amount of moisture near the surface, promoting better curing, a smoother finish, and a stronger, more uniform wall. It’s not about increasing the water-cement ratio, fostering organic growth, or leaving extra surface water after finishing.