The slump loss of concrete is usually due to which factor?

The slump loss of concrete is usually due to which factor?

• A. Didn't presoak aggregate
• B. Wrong size aggregate
• C. Not enough aggregate
• D. Low water content

Answer: (D)

Slump is a measure of how flowable the concrete is, and slump loss means that flowability decreases as time passes. The key factor that drives this decrease is the amount of free water in the mix. Water acts as the lubricant between particles, so as water evaporates, is absorbed by the aggregates, or is consumed by cement hydration, the mix stiffens and the slump drops. That’s why low water content is the usual cause of slump loss. Other factors can affect initial workability or the mix balance, but the ongoing loss of free water best explains why slump decreases over time.

Slump is a measure of how flowable the concrete is, and slump loss means that flowability decreases as time passes. The key factor that drives this decrease is the amount of free water in the mix. Water acts as the lubricant between particles, so as water evaporates, is absorbed by the aggregates, or is consumed by cement hydration, the mix stiffens and the slump drops. That’s why low water content is the usual cause of slump loss. Other factors can affect initial workability or the mix balance, but the ongoing loss of free water best explains why slump decreases over time.