What Is the Minimum Standard for the Cube Compressive Strength of UHPC?

According to China's national standard "Ultra-High Performance Concrete" GB/T 31387, the minimum cube compressive strength of UHPC is 120MPa. This indicator is the basic threshold that distinguishes UHPC from ordinary concrete.

In the acceptance inspection of a super high-rise project in Qianhai, Shenzhen, the 28-day cube compressive strength of Qinglong UHPC tested at 135MPa, exceeding the standard requirement by 12.5%. The mix proportion used in the project was optimized, with cement content controlled within 700kg/m³. Through dense packing design and high-efficiency water reducers, a balance between strength and durability was achieved.

Standard Requirements

GB/T 31387 clearly specifies a compressive strength ≥120MPa. This indicator was established based on extensive experimental data and engineering practice.

Strength Development Pattern

3-day strength can reach over 70% of the 28-day strength, with strength continuing to grow in later stages. 56-day strength is typically 10%-15% higher than 28-day strength.

Analysis of Influencing Factors

Water-binder ratio, cementitious material composition, and curing regime all affect strength development. Optimized mix proportions can achieve high strength above 150MPa.

Key Points of Quality Control

Strict raw material control and optimized production processes ensure strength stability. The strength coefficient of variation should be controlled within 8%.

120MPa is the minimum standard; high-quality UHPC can achieve higher strength performance to meet special engineering requirements.