Superplasticizers are essentially high-range water reducers meeting ASTM C 494/C 494M requirements for Type A, water-reducing, and Type F, high-range water-reducing, admixtures. These admixtures are added to concrete with a low-to-normal slump and water-cement ratio to make high-slump flowing concrete. Flowing concrete is a highly fluid but workable concrete that can be placed with little or no vibration or compaction while still remaining essentially free of excessive bleeding or segregation.
Following are a few of the applications where flowing concrete is used:
1. Concrete where high flowability, high-early and ultimate strengths and increased durability are needed.
2. Thin-section placements.
3. Areas of closely spaced and congested reinforcing steel.
4. Self-consolidating concrete.
5. Concrete where normal, mid-range, or high-range water-reduction is desired.
6. Concrete where normal setting times are required.
7. Tremie pipe (underwater) placements.
8. Pumped concrete to reduce pump pressure, thereby increasing lift and distance capacity.
9. Self-consolidating grout.
10. Areas where conventional consolidation methods are impractical or can not be used.
11. For reducing handling costs.
The addition of a plasticizer to a 3-inch slump concrete can easily produce a concrete with an 8-inch slump.
The Many Features of Superplasticizers Are:
1. Reduced water content for a given slump.
2. Dosage flexibility for normal, mid and high-range water reduction.
3. Produces cohesive and non-segregating concrete mixture.
4. Increased compressive strength and flexural strength performance at all ages.
5. Providing faster setting times and strength development.
6. Enhanced finishability and pumpability.