How to maintain the durability of UHPC?

UHPC is an advanced cementitious fiber reinforced composite material with high strength, high toughness and high durability. 

It is maintained mainly due to the following aspects:

1. Low water-bond ratio and high fines content: UHPC typically has a water-bond ratio (W/B) of 0.15-0.25, and this low W/B ratio helps improve the strength and durability of the concrete. The lower W/B ratio reduces the pores in the concrete, which reduces the permeability of water and chemicals and improves durability.
   

2. High-performance cementitious materials: Cementitious materials commonly used in UHPC include silicate cement, mineral admixtures, and fly ash, which have good reactive and cementitious properties that improve the strength and durability of concrete.
   

3. Use of chemical admixtures: Chemical admixtures added to UHPC, such as high-efficiency water-reducing agents, reinforcing agents and anti-cracking agents, can improve the fluidity, crack resistance and durability of concrete.
   

4. High-temperature maintenance and curing: During the preparation process, UHPC promotes the hydration reaction of cement through high-temperature maintenance and curing, which improves the strength and durability of concrete.
   

5. Permeability resistance: UHPC has very low permeability to water and chemicals, about one or two orders of magnitude lower than that of conventional and high performance concrete.
   

6. Carbonation resistance: UHPC rarely carbonates after 1 to 3 years of exposure, under standard curing or thermal curing. In accelerated experiments, UHPC showed excellent resistance to carbonation even after prolonged carbonation treatments.
   

7. Freeze-thaw resistance: UHPC maintains its quality, strength and durability over hundreds of freeze-thaw cycles, demonstrating excellent freeze-thaw resistance.
   

8. Chemical erosion resistance: UHPC has excellent chemical erosion resistance and can effectively resist chloride ion erosion, sulfate erosion, etc., thus extending the service life of the structure.
   

9. Fire resistance: Compared with ordinary concrete and high-performance concrete, UHPC has a slower reduction in strength at high temperatures and has better fire resistance.
   

10. Self-repairing function: Due to the presence of a large number of unhydrated cement particles inside UHPC, UHPC has a self-repairing function in case of cracking.