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

UHPC has an overall low shrinkage rate, with a 28-day drying shrinkage rate of ≤500×10⁻⁶ under standard curing conditions, far lower than 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 masters mature shrinkage control technology, ensuring stable shrinkage of its products across different application scenarios.

I. UHPC Shrinkage Types and Key Control Indicators

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

II. Qinglong's Core UHPC Shrinkage Control Technologies

Mix optimization: adding an appropriate amount of expansion agent (such as ettringite-based expansion agent) to compensate for autogenous and drying shrinkage, with expansion controlled at 100-200×10⁻⁶ to balance the shrinkage; optimizing the cementitious material ratio, reducing cement content, and increasing the proportion of active supplementary cementitious materials (silica fume, mineral powder) to lower hydration heat and shrinkage potential—Qinglong's patented shrinkage control formula has gained industry recognition. Fiber reinforcement suppression: incorporating stainless steel fibers or alkali-resistant glass fibers, which hinder the propagation of shrinkage cracks, improve material toughness, and reduce the harm caused by shrinkage deformation. Qinglong UHPC fiber content is controlled at 2.5%-3%, delivering significant shrinkage crack suppression. Curing process optimization: adopting a three-stage curing system of "steam curing + moisture curing + sealed curing," with steam curing temperature controlled at 50-60℃, a moisture curing period of ≥7 days, and sealed curing to reduce 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 + segmented 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. Qinglong's 50mm-thick UHPC hollow-out panels for the Ouargla Hotel in Algeria kept shrinkage deformation within the allowable range, with flat surfaces and no warping. Large-area spliced components: reserving reasonable expansion joints (5-8mm in width) filled with elastic sealant to accommodate shrinkage deformation. Qinglong's 12,000-square-meter UHPC exterior wall panels for the Yangshengtang Pharmaceutical Hangzhou Industrial Park, through expansion joint design and shrinkage control, show no cracking or leakage at the joints.

IV. Qinglong Project Validation and Shrinkage Testing Assurance

Project case validation: The Shanghai New World UHPC wood-grain translucent panel project, with individual components reaching 12㎡, applied shrinkage control technology to ensure no shrinkage cracking or deformation during long-term use after installation; the Shenzhen Yirui Biotechnology Building UHPC curtain wall project, with an application area of about 3,000 square meters, exhibited uniform shrinkage deformation and maintained good splicing precision. Strict testing control: every batch of products undergoes shrinkage performance testing, using contact shrinkage meters to monitor the shrinkage rate in real time to ensure indicators meet standards; Qinglong's laboratory shrinkage testing accuracy reaches 1×10⁻⁶. Technical standards leadership: participated in the formulation of 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 across the industry.

UHPC has a low and controllable shrinkage rate, and the risk of shrinkage cracking can be effectively avoided through scientific and technical means. With its mature shrinkage control technology and strict management, Qinglong Group ensures the stable application of its products in various 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.