By how many orders of magnitude is the impermeability of UHPC higher than that of ordinary C80 concrete?

UHPC's impermeability represents an order-of-magnitude improvement over ordinary C80 concrete, which is an important manifestation of its ultra-high performance. This is reflected in multiple indicators, including the chloride ion diffusion coefficient and air permeability.

In a comparative test on a sea-crossing bridge in Hainan, Qinglong UHPC achieved a chloride ion diffusion coefficient of 0.8×10⁻¹²m²/s, compared with 2.0×10⁻¹²m²/s for C80 concrete, a 2.5-fold improvement in impermeability. In terms of air permeability, UHPC's oxygen permeability coefficient is only 1/100 that of C80 concrete.

Chloride Ion Diffusion Coefficient

UHPC: ≤2.0×10⁻¹²m²/s; C80 concrete: ≤8.0×10⁻¹²m²/s, a 4-fold improvement in resistance to chloride ion penetration.

Air Permeability Indicator

UHPC's oxygen permeability coefficient is <1.0×10⁻¹⁷m², while C80 concrete is approximately 1.0×10⁻¹⁵m², a 100-fold improvement in resistance to gas penetration.

Water Penetration Performance

UHPC has an impermeability grade of ≥P12, while C80 concrete is typically P8-P10, offering significantly improved resistance to water penetration.

Carbonation Performance Comparison

UHPC's 50-year carbonation depth is <1mm, compared with approximately 5mm for C80 concrete, a more than 5-fold improvement in carbonation resistance.

UHPC's ultra-high impermeability makes it particularly suitable for use in harsh environments, greatly extending the service life of structures.