Mitigating UHPC Autogenous Shrinkage Through Material Design: Mechanism Analysis and Optimization Strategies

Solving the UHPC Autogenous Shrinkage Challenge: Material Innovation Drives Dual Breakthroughs in Architectural Aesthetics and Structural Safety

In contemporary architecture, ultra-high performance concrete (UHPC) has become the material of choice for landmark buildings and high-end decoration thanks to its outstanding mechanical properties and design freedom. However, autogenous shrinkage has long been a key bottleneck restricting its large-scale application. As an industry leader with 28 years of deep expertise in UHPC/GRC/GRG/GRP materials, Qinglong Group leverages its full-chain technical accumulation to explore autogenous shrinkage mitigation solutions from the source of material design, providing the construction industry with an innovative path that combines aesthetic expression with structural reliability.

I. Mechanism Analysis of UHPC Autogenous Shrinkage: From Microstructure to Engineering Impact

UHPC autogenous shrinkage originates from the volume changes of cement-based materials during hydration. Its core contradiction lies in the internal humidity gradient caused by high cementitious material content and a low water-binder ratio. When capillary pore water is rapidly consumed, negative pressure stress develops inside the concrete; if this stress exceeds the material's tensile strength under restrained conditions, microcracks occur. The problem is particularly prominent in thin-walled components and long-span structures, potentially leading to surface cracking, reduced durability, and other risks. Through tracking more than 2,000 engineering cases, Qinglong's technical team found that unoptimized UHPC components can exhibit autogenous shrinkage rates exceeding 800με during the curing period, significantly affecting construction precision and structural lifespan.

II. Material Design Optimization Strategies: Qinglong's Four-Dimensional Solutions from 28 Years of Technical Expertise

To tackle the autogenous shrinkage challenge, Qinglong Group has established a trinity optimization system of "material-structure-process":

1. Coordinated Regulation of the Cementitious System: A ternary composite system of "cement-slag powder-silica fume" is adopted, using the nano-scale filling effect of silica fume to refine the pore structure, combined with a specially formulated calcium aluminate expansion agent that generates moderate expansion stress in the early hydration stage to offset later shrinkage. Laboratory data show that this formulation can reduce autogenous shrinkage by more than 40% while increasing compressive strength to 150MPa.

2. Fiber Toughening and Interface Optimization: A hybrid reinforcement technology combining basalt fibers and steel fibers is introduced, with fiber volume content controlled within the 2-3% range to suppress microcrack propagation through the fiber bridging effect. Qinglong's proprietary fiber surface modification process increases interfacial bond strength by 25%, ensuring material integrity during autogenous shrinkage.

3. Intelligent Curing Process Innovation: A "gradient humidity curing system" has been developed, combining steam curing with constant temperature and humidity control to maintain relative humidity above 90% during the critical hydration period (days 1-7), slowing the rate of moisture evaporation. This process has been successfully applied in the light-transmitting concrete project at Nanjing East Road Century Plaza, where the 28-day autogenous shrinkage of components is controlled within 350με.

4. Collaborative Structural Design Optimization: BIM technology is used for pre-deformation compensation design, reserving shrinkage allowances at the detailing stage. For example, in the GRC/UHPC composite curtain wall project of the Dongguan Women and Children's Activity Center, parametric modeling achieved component installation tolerances of ≤2mm, effectively offsetting the impact of shrinkage deformation.

III. Industry Value and Application Prospects: From Technological Breakthrough to Standards Leadership

As a contributing unit to the industry standard "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)", Qinglong Group has incorporated autogenous shrinkage control technology into its corporate standard system, forming a full-process solution covering raw material selection, mix design, and construction curing. This technology is now widely applied in fields such as real estate curtain walls, municipal bridges, and cultural venues. For instance, a landmark project in Malaysia adopted Qinglong's UHPC decorative components, achieving a 10-year zero-cracking record under tropical climate conditions.

In the future, as green building and prefabricated construction advance, UHPC autogenous shrinkage control technology will become a core competitive strength in material innovation. Qinglong Group will continue to rely on its national-level R&D center platform to explore the application of cutting-edge technologies such as nanomaterials and smart sensing in autogenous shrinkage monitoring and regulation, providing more solid technical support for its mission of "Creating Aesthetic Architecture" and promoting the high-quality development of UHPC/GRC/GRG/GRP materials in the global construction market.