Material Design Mitigation Solutions for UHPC Autogenous Shrinkage: Qinglong Technical Pathway and Engineering Practice

Autogenous shrinkage is a core technical challenge UHPC (Ultra-High Performance Concrete) faces during service. If not properly controlled, it can easily cause microcracks that compromise structural durability and decorative effect. Qinglong, a national high-tech enterprise with 28 years of UHPC R&D and production experience, participated in drafting the "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)" and has developed a mature autogenous shrinkage mitigation solution through material design innovation, providing reliable assurance for designers and owners.

UHPC autogenous shrinkage originates from internal moisture consumption and volume contraction during cement hydration, essentially a contraction of the dense system caused by negative capillary pore pressure. Ordinary UHPC can reach a 28-day autogenous shrinkage value of 400-600με, while Qinglong has kept this value within 200με through optimized material design—far below the industry average. This breakthrough results from the synergistic application of four core material design strategies.

Optimizing the cementitious material system is the foundation of mitigating autogenous shrinkage. Qinglong uses low-hydration-heat high-grade cement combined with its self-developed composite mineral admixture (patented technology); through the synergistic action of fly ash, slag powder, and cement, the hydration heat peak is lowered and the hydration rate is delayed. In the Shanghai New World Nanjing East Road Century Plaza project, this system reduced the hydration heat peak of UHPC wood-imitation translucent panels by 30%, effectively reducing the risk of cracks caused by the superposition of thermal stress and autogenous shrinkage. Meanwhile, cementitious material content is precisely controlled at 800-900kg/m³ to avoid shrinkage aggravation caused by excess cement.

Precise adaptation of high-efficiency admixtures is key. Qinglong uses a combination of polycarboxylate superplasticizer and retarding water-retention agent, lowering the water-binder ratio to 0.16-0.20 while improving the water retention of the mix and reducing internal moisture evaporation. Its self-developed autogenous shrinkage inhibitor (already granted an invention patent) further reduces the shrinkage rate by adjusting the structure of hydration products. In the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, this admixture combination reduced the early autogenous shrinkage rate of UHPC exterior wall panels by 40%, ensuring the forming quality of thin-walled components.

Optimized aggregate gradation and fiber modification provide double assurance. Qinglong uses continuously graded aggregates composed of quartz sand and emery to fill gaps between cementitious materials, increase system compactness, and reduce space for shrinkage; meanwhile, 1-2% alkali-resistant glass fiber and steel fiber are added to inhibit the propagation of shrinkage cracks through the bridging effect of fibers. In the Ouargla Hotel UHPC hollow panel project in Algeria, fiber modification technology ensured that no shrinkage cracks appeared in the components during long-term service, fully verifying the effectiveness of the solution.

Leveraging the technical strength of its provincial-level R&D center, Qinglong deeply integrates material design with engineering practice, and its autogenous shrinkage control technology has been successfully applied to thousands of UHPC projects. For designers and owners, choosing a supplier with material design innovation capability is key to avoiding UHPC autogenous shrinkage risks. Adhering to the motto of "meticulous attention to detail and constant pursuit of excellence," Qinglong continuously optimizes its autogenous shrinkage mitigation solutions, enabling UHPC materials to deliver more stable performance advantages in architectural decoration.