Dampening the subgrade or wood forms prior to concrete placement serves what primary purpose?

Dampening the subgrade or wood forms prior to concrete placement serves what primary purpose?

• A. Increase curing speed
• B. Prevent rapid extraction of mixing water
• C. Improve adhesion of finish
• D. Reduce thermal expansion

Answer: (B)

Dampening the subgrade or wooden forms before placing concrete primarily serves to prevent the rapid extraction of mixing water from the freshly mixed concrete. When concrete is poured, it contains a specific amount of water that is critical for the hydration process, which ultimately affects the strength and durability of the cured concrete. If the subgrade or forms are too dry, they can absorb moisture from the concrete mix, leading to a reduction in the water available for hydration. This can cause issues such as incomplete curing, shrinkage cracks, or reduced strength. By wetting these surfaces ahead of time, it helps to create a more uniform environment for the concrete, ensuring that the water content remains adequate for proper curing. This practice is standard in concrete work to enhance the overall performance and longevity of the concrete slab being poured.

Dampening the subgrade or wooden forms before placing concrete primarily serves to prevent the rapid extraction of mixing water from the freshly mixed concrete. When concrete is poured, it contains a specific amount of water that is critical for the hydration process, which ultimately affects the strength and durability of the cured concrete. If the subgrade or forms are too dry, they can absorb moisture from the concrete mix, leading to a reduction in the water available for hydration. This can cause issues such as incomplete curing, shrinkage cracks, or reduced strength.

By wetting these surfaces ahead of time, it helps to create a more uniform environment for the concrete, ensuring that the water content remains adequate for proper curing. This practice is standard in concrete work to enhance the overall performance and longevity of the concrete slab being poured.