CSLB Class B General Contractor's License Practice Exam

What does a high slump value in concrete represent?

1. Too much air

2. Too much water

3. Too much aggregate

4. Low strength

The correct answer is: Too much water

A high slump value in concrete indicates that the concrete mix has a high workability, which is often a result of an excess of water in the mix. Slump is a measure of the consistency and fluidity of the concrete; the higher the slump, the more fluid the concrete is. This is particularly important for applications where the concrete needs to flow easily into forms or around rebar. When the concrete has too much water, it increases the slump value, making the mix easier to work with initially. However, while high slump may facilitate workability during application, it can lead to serious long-term issues with strength and durability. Excess water can compromise the mix's strength by creating voids and reducing the overall density of the cured concrete. This is why a high slump value often signals potential concerns regarding the concrete's final structural integrity. Other choices, while related to concrete mixing, do not directly correlate to a high slump scenario as accurately as the excess water does. Recognizing that a high slump pertains to water content is crucial for ensuring the right balance in concrete mixes for construction practices.