what should be done to a concrete mix to increase ease of a pour?

what should be done to a concrete mix to increase ease of a pour?

• A. Decrease rough aggregate
• B. Increase sand
• C. Decrease temperature
• D. Increase temperature

Answer: (A)

Reducing internal friction inside the mix is the key to making concrete easier to pour. Rough aggregate surfaces catch on each other and on the cement paste, creating resistance to flow. By using less rough (smoother) aggregate, the particles slide past one another more easily and the paste can flow around them, so the mix pours more readily. Other options change flow in less direct or more problematic ways. Increasing temperature can make the paste flow more initially but speeds up setting, while decreasing temperature stiffens the mix. Adding more sand changes the fines content and water demand, which can also alter workability in less predictable ways. So smoothing the aggregate surface is the most straightforward way to ease pouring.

Reducing internal friction inside the mix is the key to making concrete easier to pour. Rough aggregate surfaces catch on each other and on the cement paste, creating resistance to flow. By using less rough (smoother) aggregate, the particles slide past one another more easily and the paste can flow around them, so the mix pours more readily.

Other options change flow in less direct or more problematic ways. Increasing temperature can make the paste flow more initially but speeds up setting, while decreasing temperature stiffens the mix. Adding more sand changes the fines content and water demand, which can also alter workability in less predictable ways. So smoothing the aggregate surface is the most straightforward way to ease pouring.