Ultra-High Performance Concrete (UHPC) is characterized by
- ACompressive strengths typically exceeding 120-150 MPa and excellent durability.Correct
- BA very high water-cement ratio to ensure flowability.
- CThe absence of any fine aggregates or silica fume.
- DIts inability to resist any tensile loads.
Solution
Concept
Ultra-High Performance Concrete (UHPC) Properties
Formula
N/A
Step-by-step solution
1. Review the characteristics of Ultra-High Performance Concrete (UHPC). 2. Recall that UHPC achieves compressive strengths above 120–150 MPa and exceptional durability due to low water content and dense packing. 3. Compare with the options and select Option (a) as the correct choice.
Explanation
Ultra-High Performance Concrete (UHPC) is an advanced material formulated with a dense microstructure and low water content, allowing it to achieve extremely high compressive strengths (usually above 120–150 MPa). This tight packing of particles also prevents water and harmful chemicals from penetrating, giving it outstanding durability and a long lifespan compared to regular concrete.
Shortcut
To easily remember UHPC characteristics, use the mnemonic "UHPC = Ultra High Power & Compact": - High Power: Extreme compressive strength exceeding 120–150 MPa. - Compact & Durable: Dense particle packing with low water content ensures exceptional durability.
Common mistake
A common mistake is selecting Option B by assuming that flowability requires a high water-cement ratio, whereas UHPC achieves high flowability using superplasticizers while keeping a very low water-cement ratio. Another frequent error is selecting Option C by assuming silica fume is excluded, when in fact fine particles like silica fume are essential for achieving its dense microstructure and high strength.
Correct answer: A) Compressive strengths typically exceeding 120-150 MPa and excellent durability.