In MOST construction sites, water is allowed to be added to the concrete as long as?

In MOST construction sites, water is allowed to be added to the concrete as long as?

• A. The temperature does not rise
• B. Maximum slump is 4 inches
• C. Water and cement ratio are not to be exceeded
• D. Concrete slump is kept within an allowed range

Answer: (C)

The important concept is that the water-to-cement ratio set in the mix design controls the strength and durability of the concrete, and you cannot on site exceed that ratio. Water added beyond the designed ratio weakens the concrete because it increases porosity as the extra water evaporates, leaving a softer, less durable matrix. So water can be added only if it does not push the water-to-cement ratio past what the mix design specifies. If more workability is needed, use an approved admixture or adjust the mix design rather than just adding water. Other options aren’t the governing rule: simply keeping slump within a certain range doesn’t authorize adding water, because adding water changes the ratio; temperature rise or maximum slump values are measures of fresh concrete properties but don’t sanction increasing the water content beyond the designed ratio.

The important concept is that the water-to-cement ratio set in the mix design controls the strength and durability of the concrete, and you cannot on site exceed that ratio. Water added beyond the designed ratio weakens the concrete because it increases porosity as the extra water evaporates, leaving a softer, less durable matrix. So water can be added only if it does not push the water-to-cement ratio past what the mix design specifies. If more workability is needed, use an approved admixture or adjust the mix design rather than just adding water.

Other options aren’t the governing rule: simply keeping slump within a certain range doesn’t authorize adding water, because adding water changes the ratio; temperature rise or maximum slump values are measures of fresh concrete properties but don’t sanction increasing the water content beyond the designed ratio.