What Is the Minimum Standard for the Cubic Compressive Strength of UHPC? Strength Grade Classification and Qinglong Group's Quality Control System

According to major domestic and international standards, the minimum standard for the cubic compressive strength of UHPC is 120MPa, which is the key threshold distinguishing UHPC from high-performance concrete (HPC). The 'General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)', for which Qinglong Group participated in drafting, clearly stipulates that the 28-day cubic compressive strength of UHPC shall not be lower than 120MPa, and premium products should reach above 150MPa. In our actual production, through maximum packing density design and steam curing processes, compressive strength is stably controlled within the range of 150-180MPa. In projects such as the Wuhan Han Show Theater and the Hainan International Convention and Exhibition Center, measured strengths exceeded the standard requirements by more than 30%, providing full assurance for building safety.

Strength grade classification reflects performance differences. We divide UHPC into three grades: Standard grade (120-150MPa), High-Strength grade (150-180MPa), and Ultra-High-Strength grade (>180MPa). Different grades correspond to different application scenarios: Standard grade is suitable for general curtain wall panels, High-Strength grade is used for load-bearing components, and Ultra-High-Strength grade is used for special structures. All Qinglong Group products reach High-Strength grade or above, meeting the most demanding engineering requirements.

Strength control requires systematic measures. Starting with raw materials, we select Grade 52.5 low-alkali cement and highly active supplementary cementitious materials; during production, steam curing (60-80℃) promotes strength development; in testing, one set of samples is taken for every 100m³, with the strength coefficient of variation controlled within 5%. This whole-process control ensures strength stability.

Strength is not the only indicator; it needs to be considered together with toughness and durability. While maintaining high strength, Qinglong UHPC achieves a flexural toughness index exceeding 40, realizing the optimal balance between strength and toughness. We recommend that users select an appropriate strength grade according to the specific application.