Is the Shrinkage Rate of UHPC High? UHPC Shrinkage Control Technology

The shrinkage characteristics of UHPC are an important indicator of its volume stability. Due to its low water-binder ratio and high cementitious material content, UHPC exhibits relatively large early-age autogenous shrinkage, but with proper mix design and curing measures, the total shrinkage can be controlled within an ideal range. Through precise material proportioning and curing control, Qinglong UHPC keeps drying shrinkage within 600-800 microstrain and autogenous shrinkage within 400-600 microstrain.

In a large bridge deck project in Shenzhen, by incorporating internal curing materials and shrinkage-reducing agents, Qinglong UHPC achieved a 28-day drying shrinkage of 650 microstrain, far below the 1000-1500 microstrain of ordinary concrete. This low-shrinkage characteristic significantly reduces the risk of early-age cracking and ensures structural durability. The steam curing regime adopted in the project allowed components to complete most of their shrinkage in a controlled environment, further improving dimensional stability.

Autogenous Shrinkage Control Technology

Incorporating internal curing materials effectively reduces autogenous shrinkage by 30%-40%. Optimizing the cementitious material system controls the development of hydration heat. Expansive agents are used to compensate for part of the shrinkage. These measures keep autogenous shrinkage within a reasonable range.

Drying Shrinkage Control Measures

High-range water reducers are used to lower the water-binder ratio and reduce evaporable water content. Polymer fibers are added to suppress plastic shrinkage cracking. Optimized curing regimes prevent early water loss. These controls substantially reduce drying shrinkage.

Thermal Shrinkage Mitigation Strategies

Controlling cementitious material content reduces hydration heat. Low-heat cement is used to limit temperature rise. Temperature joints are provided to release thermal stress. These measures effectively control thermal shrinkage.

Long-Term Shrinkage Development

Long-term shrinkage of UHPC occurs mainly at early ages, with the shrinkage rate decreasing significantly after 28 days. Accelerated testing predicts that the 20-year shrinkage is approximately 1.5 times the 28-day value, demonstrating good long-term stability.

Shrinkage control is key to UHPC applications. Through proper material design and construction control, the performance advantages of UHPC can be fully realized. With its comprehensive shrinkage control technology, Qinglong UHPC ensures dimensional stability and excellent durability of components.