Florida DOT Concrete Batchman/Operator Practice Exam

Which benefit does high-range water reducer provide concerning strength?

1. Decreases overall strength

2. Increases overall strength

3. Maintains the same strength

4. Weakens the mix

The correct answer is: Increases overall strength

High-range water reducers, also known as superplasticizers, are additives used in concrete mixtures to significantly improve the flow of the mix without adding extra water. When used correctly, they allow for a reduction in the water-to-cement ratio, which is essential for improving the overall strength of the concrete. The primary benefit of using a high-range water reducer is that it enhances the workability of the concrete while maintaining, or even increasing, the compressive strength. By reducing the water content and allowing for better cement hydration, these additives help the concrete maintain its desired strength characteristics. This results in a denser, less permeable concrete that is more resistant to cracking and damage over time. Thus, the choice indicating an increase in overall strength is accurate, as the high-range water reducer effectively contributes to producing stronger concrete mixtures than would be achieved by simply adding more water or maintaining the same water-to-cement ratio.