ASTM C143 slump is a workability index, not a strength input. Extra mix water raises slump and lowers f'c (w/c). Superplasticizers raise slump at constant w/c. Do not add water on site without a mix redesign.
slump(in)
Measured settlement of the cone
w/c
Water–cement ratio
Step-by-step solved example
Cone 12 in, settled height 8 in. Slump? If water is added to go from 3 in to 6 in, f'c typically?
Slump cone before and after settlement (12 in cone).
1. Slump
12−8=4 in.
2. Water
More water at the same cement raises w/c and drops f'c and durability.
Answer: Slump=4 in; added water lowers f'c
10 practice questions
0/10 correct
1.Standard slump cone height is
2.A 1 in slump mix is
3.Superplasticizer at constant w/c
4.Air-entraining admixture primarily
5.Slump flow (spread) is used for
6.Time after batching: slump
7.w/c is the primary controller of
8.Maximum slump in a spec is there to
9.If settled height equals 12 in, slump=
10.Unit weight of fresh concrete is checked because