How Big Is the Performance Difference Between Non-Steam-Cured UHPC and Steam-Cured UHPC?

The core performance differences between non-steam-cured UHPC and steam-cured UHPC lie in strength development rate, densification, and production cycle. Steam curing can accelerate performance improvement, but non-steam-cured UHPC can reach near steam-cured levels through material optimization. Qinglong's non-steam-curing technology narrows the 28-day performance gap between the two to within 10%, meeting the needs of different projects.

I. Strength Performance Differences: Steam Curing Accelerates, Non-Steam Curing Improves Steadily

The strength difference is mainly evident in the early stage and converges in the later stage. Early strength (7 days): steam-cured UHPC (90℃ steam curing for 48 hours) achieves a compressive strength of 140-160MPa, while non-steam-cured UHPC reaches 100-120MPa, a difference of about 30%; later strength (28 days): steam-cured UHPC has a compressive strength of 150-180MPa, while non-steam-cured UHPC is 130-160MPa, with the difference narrowing to 10%-15%; long-term strength (1 year): the strength of both stabilizes, with a difference of ≤8%; Qinglong's non-steam-cured UHPC reaches a 1-year compressive strength of 165MPa, close to the level of steam-cured products; flexural strength: the difference pattern is consistent with compressive strength; at 28 days, non-steam-cured UHPC has a flexural strength of ≥18MPa and steam-cured products ≥20MPa, both meeting high-end application requirements.

II. Densification and Durability Differences: Steam Curing Is Superior, Non-Steam Curing Meets Standards

Differences in densification directly affect durability performance. Porosity: steam-cured UHPC has a total porosity of ≤2% with closed pores accounting for ≥90%; non-steam-cured UHPC has a total porosity of ≤3% with closed pores accounting for ≥85%; through particle gradation optimization, Qinglong's non-steam-cured UHPC achieves porosity close to the steam-cured level; impermeability: steam-cured UHPC has an impermeability grade of ≥P30 and non-steam-cured ≥P25, both far exceeding ordinary concrete; freeze-thaw resistance: both meet the requirement of ≤5% strength loss after 300 freeze-thaw cycles; Qinglong's non-steam-cured UHPC suffered no damage after 6 years of freeze-thaw in a Northeast China project; corrosion resistance: steam-cured UHPC has a lower chloride ion penetration coefficient (≤0.5×10⁻¹²m²/s), while non-steam-cured is ≤1.0×10⁻¹²m²/s; coastal projects should give priority to steam-cured products, while non-steam-cured is fully suitable for inland projects.

III. Production Cycle and Cost Differences: Non-Steam Curing Offers Greater Flexibility

Differences in production characteristics determine the suitable project scenarios. Production cycle: the total cycle for steam-cured UHPC is 7-10 days (mixing and pouring + 48 hours of steam curing + later-stage curing), while non-steam-cured requires 14-21 days, with steam curing improving efficiency by 50%; equipment investment: steam curing requires a steam curing kiln (investment of approximately RMB 500,000-1 million), while non-steam curing requires no additional equipment; Qinglong's production base in Nanning, Guangxi has both steam-cured and non-steam-cured production lines, switchable as needed; cost difference: the unit cost of steam-cured UHPC is 10%-15% higher than non-steam-cured (including equipment depreciation and energy consumption), so cost-sensitive projects can choose non-steam-cured UHPC; project cases: Qinglong's Shenzhen Yirui Biotechnology Building (non-steam-cured, 3,000 ㎡ exterior wall panels) and Shanghai New World Plaza (steam-cured, special-shaped light-transmitting components) respectively suit projects prioritizing construction schedule and performance.