How to Mitigate UHPC Autogenous Shrinkage Through Material Design: Mechanism Analysis and Optimization Strategy Research

Solving the UHPC Autogenous Shrinkage Challenge: Material Innovation Drives the Perfect Balance Between Architectural Aesthetics and Structural Safety

In contemporary architectural design, UHPC (Ultra-High Performance Concrete) has become the material of choice for high-end buildings such as grand theaters and commercial complexes, thanks to its outstanding mechanical properties and design freedom. However, autogenous shrinkage has long been a technical bottleneck restricting its large-scale application—excessive shrinkage may cause component cracking, reduced structural stability, and even compromise the overall safety of a building. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group has drawn on more than a thousand engineering projects to develop a systematic shrinkage mitigation solution from the fundamental principles of material design, providing designers and owners with solutions that combine aesthetic expression with structural reliability.

The Formation Mechanism of UHPC Autogenous Shrinkage: From Material Properties to Microstructure

UHPC autogenous shrinkage is essentially the result of the combined effects of hydration reactions in cement-based materials and internal moisture migration. Its ultra-high cementitious material content (typically exceeding 800kg/m³) and low water-binder ratio (0.15-0.25) system cause the chemical shrinkage produced during hydration and the drying shrinkage induced by capillary pore negative pressure to superimpose, ultimately resulting in significant volumetric deformation. Observations through scanning electron microscopy (SEM) at Qinglong's R&D Center revealed that conventional UHPC can exhibit an autogenous shrinkage rate of 400-600με within 7 days of curing—far exceeding that of ordinary concrete—posing a severe challenge to the dimensional stability of thin-walled components (such as UHPC facade cladding panels and sunshades).

Material Design Optimization Strategy: Qinglong's Three-Dimensional Solution Built on 28 Years of Technical Expertise

To address the autogenous shrinkage challenge, Qinglong Group has established a three-dimensional technical framework of "raw material regulation – microstructure optimization – curing process innovation." At the raw material level, a composite admixture system of "nano calcium carbonate + ultra-fine silica fume" is used to fill the gaps in cement hydration through optimized particle grading, reducing the number of capillary pores. Meanwhile, modified polypropylene fibers are introduced, leveraging their bridging effect to suppress microcrack propagation; experimental data show that this formulation can reduce the autogenous shrinkage rate by more than 30%. In mix proportion design, the steel fiber volume content is innovatively controlled within the range of 2.0-2.5%, which not only ensures mechanical performance (compressive strength ≥150MPa) but also relieves shrinkage stress through the fiber skeleton effect.

Innovation in curing processes is equally critical. Qinglong's independently developed "gradient moist curing + heat curing" composite process suppresses surface moisture evaporation through an early-stage 90% humidity environment, followed by 60℃ steam curing to accelerate the hydration process, enabling rapid early-age strength development in UHPC and thereby locking in most of the shrinkage. Practice at the Nanning production base shows that UHPC components produced with this process can maintain a stable 28-day autogenous shrinkage value within 250με, fully meeting the requirements of the industry standard "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)."

Engineering Validation and Full-Chain Assurance: Closed-Loop Management from Laboratory to Project Site

The value of technology must ultimately be verified through engineering practice. In the Century Plaza renovation project on Nanjing East Road, Qinglong's customized autogenous shrinkage control solution for translucent concrete components successfully solved the assembly precision challenge of a 30m-span irregular curtain wall, and the project won the Silver Award at the First UHPC Architectural Engineering Innovation Awards sponsored by AALBORG WHITE. Behind this achievement lies Qinglong's full-chain service capability: from shrinkage simulation with BIM models during the detailed design stage, to intelligent curing monitoring systems in production, and then to 3D laser positioning technology during construction and installation—forming a comprehensive quality control system covering "design-production-construction."

As a National High-Tech Enterprise and a participant in UHPC standard development, Qinglong Group has always upheld the mission of "creating beautiful architecture," deeply integrating material innovation with engineering practice. Facing the industry-wide challenge of UHPC autogenous shrinkage, we firmly believe that scientific material design and rigorous process control can not only overcome this technical bottleneck but also unlock greater potential for UHPC in architectural decoration. Moving forward, Qinglong will continue to explore low-carbon UHPC material systems, striving steadily toward its vision of "becoming a world-class leading manufacturer of UHPC/GRC/GRG/GRP."