Is UHPC Shrinkage Rate High? Qinglong UHPC Shrinkage Control Technology and Application Assurance

UHPC has an overall low shrinkage rate: under standard curing conditions, its 28-day drying shrinkage is ≤500×10⁻⁶, far lower than that of ordinary concrete (800-1000×10⁻⁶). Through scientific mix optimization and curing processes, the shrinkage rate can be further controlled within 300×10⁻⁶, effectively preventing structural damage caused by shrinkage cracking. Qinglong Group has been deeply engaged in the UHPC field for 28 years and has mastered mature shrinkage control technology, ensuring stable shrinkage performance of its products across different application scenarios.

I. UHPC Shrinkage Types and Core Control Indicators

Drying shrinkage: volumetric shrinkage caused by moisture evaporation when UHPC is in a dry environment. Qinglong standard UHPC has a 28-day drying shrinkage of ≤450×10⁻⁶, with shrinkage tending to stabilize at 60 days and a final shrinkage of ≤500×10⁻⁶. Autogenous shrinkage: volumetric shrinkage resulting from the consumption of internal moisture during the hydration reaction. The low water-binder ratio of UHPC makes autogenous shrinkage relatively pronounced; Qinglong controls autogenous shrinkage within 200×10⁻⁶ by adding expansive agents, preventing the formation of internal cracks. Thermal shrinkage: volumetric deformation caused by temperature changes. UHPC has a low thermal conductivity (0.8-1.0 W/(m·K)) and a thermal shrinkage coefficient of ≤12×10⁻⁶/℃. Qinglong products have passed temperature cycling tests, showing uniform shrinkage deformation with no obvious cracking.

II. Qinglong's Core Technologies for UHPC Shrinkage Control

Mix optimization and adjustment: adding an appropriate amount of expansive agent (such as an ettringite-type expansive agent) to compensate for autogenous and drying shrinkage, with the expansion amount controlled at 100-200×10⁻⁶ to balance the shrinkage; optimizing the proportion of cementitious materials, reducing cement content, and increasing the share of active admixtures (silica fume, mineral powder) to lower hydration heat and shrinkage potential. Qinglong's patented shrinkage control formula has gained industry recognition. Fiber-reinforced suppression: incorporating stainless steel fibers or alkali-resistant glass fibers, which can hinder the propagation of shrinkage cracks, improve material toughness, and reduce the harm caused by shrinkage deformation. Qinglong UHPC has a fiber content controlled at 2.5%-3%, achieving a remarkable effect in suppressing shrinkage cracks. Curing process optimization: adopting a three-stage curing system of “steam curing + moisture curing + sealed curing”, with the steam curing temperature controlled at 50-60℃ and a moisture curing period of ≥7 days, while sealed curing reduces moisture evaporation. Qinglong's curing process reduces product shrinkage by 20%-30%.

III. Shrinkage Control Solutions for Different Application Scenarios

Large integrated components: adopting a low-shrinkage formula combined with staged curing to reduce overall shrinkage deformation. Qinglong's 3-meter-high UHPC sculpture for the Shanghai Astronomy Museum, through precise shrinkage control, was formed in one piece with no shrinkage cracks. Thin-walled decorative components: optimizing fiber content and curing processes to prevent warping and cracking of thin-walled components caused by shrinkage. For Qinglong's 50mm-thick UHPC hollow panels at the Ouargla Hotel in Algeria, shrinkage deformation is controlled within allowable limits, with flat surfaces and no warping. Large-area spliced components: reserving reasonable expansion joints (width 5-8mm) filled with elastic sealant to accommodate shrinkage deformation. For Qinglong's 12,000-square-meter UHPC exterior wall panels at the Yangshengtang Pharmaceutical Hangzhou Industrial Park, thanks to expansion joint design and shrinkage control, the joints show no cracking or leakage.

IV. Qinglong Project Evidence and Shrinkage Testing Assurance

Project case verification: in the Shanghai New World UHPC wood-effect translucent panel project, a single component covers an area of up to 12 m²; through shrinkage control technology, there has been no shrinkage cracking or deformation over long-term use after installation. In the UHPC curtain wall project for the Shenzhen Yirui Biotechnology Building, with an application area of about 3,000 square meters, shrinkage deformation is uniform and jointing precision remains excellent. Strict testing and control: every batch of products undergoes shrinkage performance testing, with contact-type shrinkage meters used to monitor the shrinkage rate in real time to ensure all indicators meet standards; the shrinkage testing precision of Qinglong's laboratory reaches 1×10⁻⁶. Leading technical standards: Qinglong participated in formulating the “General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)”, clarifying shrinkage performance control indicators and testing methods, and promoting the standardization of shrinkage control technology in the industry.

UHPC has a low and controllable shrinkage rate, and the risk of shrinkage cracking can be effectively avoided through scientific and technological means. With its mature shrinkage control technology and strict quality control, Qinglong Group ensures the stable application of its products in all types of projects. Choosing a professional manufacturer with shrinkage control capabilities is key to ensuring the long-term stability of UHPC projects and avoiding later maintenance costs.