How to Select UHPC Reinforcement Components for Old Building Renovation?

Selecting UHPC reinforcement components for existing building renovation requires comprehensive consideration of the original structural condition, reinforcement objectives, and construction conditions. Based on experience from multiple historic building renovation projects, Qinglong Group has summarized a three-step selection method—condition assessment, performance matching, and construction feasibility—to ensure optimal reinforcement results.

Condition assessment is the foundation of selection. Core drilling, rebar scanning, and load testing are used to comprehensively evaluate the structural condition. In the renovation of a historic building in Wuhan, Qinglong Group used ultrasonic testing to measure concrete strength and infrared thermal imaging to detect defects, providing a basis for component selection. Based on the test results, structures are classified as intact, slightly damaged, or severely damaged, each corresponding to different reinforcement schemes. Intact structures can adopt thin-layer UHPC (20-30mm thick) for protective reinforcement, while damaged structures require structural reinforcement panels (50-80mm thick).

Performance matching ensures effective reinforcement. Deformation compatibility between new and old materials is critical—the elastic modulus of UHPC (40-50GPa) must match that of old concrete (30GPa). Qinglong Group controls the deformation difference within 15% by adding elastic modulus modifiers. The coefficient of thermal expansion of reinforcement components must also be similar to avoid thermal stress. In the renovation of an office building in Nanning, material optimization enabled new and old components to work in coordination.

Construction feasibility determines whether a scheme can be implemented. Cast-in-place UHPC requires consideration of formwork and curing conditions, while precast panel installation requires solving connection issues. In the renovation of a commercial building in Shenzhen, Qinglong Group used 30mm-thick precast UHPC panels connected to the original structure with chemical anchors, shortening the construction period by 50%. For areas with limited space, sprayed UHPC technology is adopted, achieving a minimum thickness of 15mm. Through scientific selection, UHPC reinforcement both enhances structural performance and preserves the building's historical value.