What Are the Material Requirements for Embedded Parts Used in UHPC Component Installation?

The material selection for embedded inserts in UHPC component installation directly affects connection safety and durability. Based on 28 years of engineering experience, Qinglong Group requires that insert materials meet three major requirements: corrosion resistance, high strength, and compatibility. Preferred materials include austenitic stainless steel (304/316), hot-dip galvanized steel, and titanium alloy, ensuring long-term stability in the highly alkaline environment of UHPC.

Corrosion resistance is the primary requirement. The pH value of the UHPC matrix exceeds 12.5, making ordinary carbon steel prone to electrochemical corrosion. Qinglong Group mandates the use of stainless steel grade 304 or higher (chromium content ≥18%, nickel content ≥8%), upgraded to 316 stainless steel (molybdenum content 2%-3%) in coastal areas. In the Hainan International Convention and Exhibition Center project, 316 stainless steel inserts showed no rust after 5 years of use, with tensile strength retention above 95%. Insert surfaces must be smooth and free of burrs to avoid stress concentration.

Strength requirements ensure safety. The tensile strength of inserts must be no less than 500MPa, and the bond strength with UHPC ≥2MPa. Qinglong Group uses machine-threaded rods with thread accuracy of class 6g to ensure anchoring effectiveness. In the Shenzhen Yirui Biotechnology Building project, M12 inserts achieved a pull-out force of 15kN, with a safety factor of 2.5. For critical connection points, physical pull-out tests are conducted to verify load-bearing capacity.

Compatibility prevents adverse reactions. The coefficient of thermal expansion of the insert must match that of UHPC, with the difference controlled within 2×10⁻⁶/℃. In projects located in regions with large temperature differences, Qinglong Group uses stainless steel whose thermal expansion coefficient is close to that of UHPC, reducing thermal stress. Inserts must be installed with accurate positioning, with an error ≤3mm, to ensure reasonable load distribution. Through strict material control, UHPC component connection systems can achieve a design service life of 50 years.