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

Material design is the key to solving the UHPC autogenous shrinkage challenge. With 28 years of industry experience, Qinglong Group provides systematic solutions for ultra-high performance concrete applications through its full-chain technical capabilities.

In the field of building materials, ultra-high performance concrete (UHPC) is becoming the material of choice for landmark buildings, high-end curtain walls, and other applications, thanks to its outstanding mechanical properties and durability. However, autogenous shrinkage has always been a key bottleneck restricting the large-scale application of UHPC. The risk of internal microcracks not only affects structural stability but may also undermine the material's long-term service life. As an industry leader with 28 years of expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group draws on its full-chain experience in detailed design, manufacturing, and construction installation to explore pathways for mitigating autogenous shrinkage from the very nature of the material, providing the industry with technical references that combine theoretical depth and practical value.

Mechanism Analysis of UHPC Autogenous Shrinkage: From Microstructure to Macroscopic Behavior

The essence of UHPC autogenous shrinkage is the volume deformation of cement-based materials during hardening, caused by the combined effects of chemical shrinkage and capillary pore negative pressure. Compared with ordinary concrete, UHPC's extremely high cementitious material content and very low water-binder ratio make its internal moisture more readily consumed by the cement hydration reaction, thereby inducing more significant shrinkage stress. Through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, Qinglong Group's R&D Center found that unoptimized UHPC systems can exhibit autogenous shrinkage values exceeding 800με at 28 days of age, far exceeding the 300με threshold of ordinary concrete—posing severe challenges to component dimensional accuracy and structural safety.

Material Design Optimization Strategies: Qinglong Group's Three-Dimensional Solutions

To address UHPC autogenous shrinkage, Qinglong Group has built a mitigation system across three dimensions: material composition design, microstructure regulation, and coordinated process optimization. In raw material selection, the incorporation of ultra-fine silica fume and nano calcium carbonate optimizes the packing density of cement hydration products and reduces the number of capillary pores; a composite system of a new calcium aluminate expansion agent and MgO utilizes the hydration expansion effect to compensate for shrinkage, verified by experiments to reduce autogenous shrinkage by more than 35%. In fiber reinforcement, the Qinglong team innovatively combines basalt fibers with steel fibers, which not only enhances material toughness but also suppresses the initiation and propagation of shrinkage cracks through the fiber bridging effect.

Coordinated optimization of production processes is equally critical. At its production base in Nanning, Guangxi, Qinglong Group has introduced an intelligent temperature control system that applies gradient heating and constant-temperature moisture retention during the pre-curing stage to slow the early hydration rate of cement and reduce shrinkage stress concentration. For large UHPC components, the "segmental casting + post-tensioned prestressing" process is adopted, using mechanical stress to offset part of the shrinkage deformation. This technology has been successfully applied to the translucent concrete project of the Century Plaza renovation on Nanjing East Road, achieving zero-crack delivery of complex curved components.

Full-Chain Service Assurance: Closed-Loop Management from Laboratory to Construction Site

As a national high-tech enterprise, Qinglong Group emphasizes integrated services spanning "material R&D - detailed design - construction control." In the early stages of a project, the technical team customizes UHPC mix proportion designs according to specific project requirements and predicts shrinkage trends using thermodynamic simulation software. During production, BIM technology is used for digital pre-assembly of components, with shrinkage compensation allowances reserved. During construction, dedicated curing equipment ensures that components achieve strength development and shrinkage stability in a standard temperature and humidity environment. This full-process control model has enabled Qinglong UHPC products to achieve industry-leading dimensional deviation control within ±2mm from production to installation in landmark projects such as the Dongguan Women and Children's Activity Center.

Facing the industry-wide challenge of UHPC autogenous shrinkage, Qinglong Group has demonstrated through 28 years of technical accumulation and engineering practice that scientific material design and a systematic service system can fully transform challenges into technical advantages. Going forward, as industry standards such as the "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)" are gradually improved, Qinglong will continue to focus on the innovative development of UHPC/GRC/GRG/GRP materials. Guided by the values of "honesty, perseverance, trust, and collaboration," the company will provide higher-quality material solutions for the global architectural decoration field, helping to realize its corporate mission of "creating beautiful architecture."