What Is the Reserved Expansion Joint Width for UHPC Facade Lines? Design Specifications and Construction Key Points Explained

Details determine quality. Precise control of expansion joint width provides dual assurance of safety and aesthetics for UHPC exterior wall profiles.

In the field of modern architectural decoration, UHPC (Ultra-High Performance Concrete), with its outstanding mechanical properties and design expressiveness, has become the ideal choice for high-end building exterior wall profiles. However, as an industry leader with 28 years of full-chain experience in the UHPC/GRC/GRG/GRP materials field, Qinglong Group understands deeply that the reserved width design of expansion joints is a critical factor affecting the durability and safety of UHPC exterior wall profiles. Combining design specifications with construction practice, this article analyzes the technical essentials of reserved expansion joint width for UHPC exterior wall profiles, providing professional solutions for designers and owners.

I. Design Specification Requirements for Expansion Joints of UHPC Exterior Wall Profiles

According to industry standards such as the "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)" (Plan No. 2024-0232T-JC), the reserved width of expansion joints for UHPC exterior wall profiles must comprehensively consider three major factors: material characteristics, ambient temperature differences, and component length. Generally, UHPC profiles with straight sections longer than 6 meters should have expansion joints, with joint width preferably controlled between 10-20mm. For projects in severely cold regions or with intense sunlight exposure, the upper limit of 20mm is recommended to accommodate greater thermal deformation; while in mild climate regions, a joint width of 10-15mm is sufficient. Multiple industry standards that Qinglong Group participated in formulating explicitly state that expansion joint width must be designed in coordination with the settlement joints and temperature joints of the building's main structure, so as to avoid profile cracking caused by stress concentration.

II. Analysis of Core Factors Affecting Expansion Joint Width

1. Material Shrinkage Characteristics: UHPC material undergoes a certain degree of drying shrinkage and carbonation shrinkage during curing. Through precise control of the water-binder ratio and curing processes, Qinglong's production base keeps the shrinkage value stable within 0.03%, providing data support for expansion joint width design. 2. Thermal Deformation Coefficient: The linear expansion coefficient of UHPC is approximately 10×10⁻⁶/℃. When the ambient temperature changes by 50℃, a 10-meter-long profile will produce 5mm of deformation, so the joint width requires sufficient buffer space. 3. Installation Method Differences: UHPC profiles with rigid fixing require enlarged joint widths, while flexible connections (such as elastic rubber strip sealing) can be appropriately reduced, but the minimum width should not be less than 10mm—a parameter verified in the Century Plaza renovation project on Nanjing East Road undertaken by Qinglong.

III. Key Points for Expansion Joint Treatment During Construction

As a national-level high-tech enterprise integrating detailed design, manufacturing, and construction installation, Qinglong has summarized a three-step construction method to ensure expansion joint quality: first, joint grooves are precisely reserved during the factory prefabrication stage, using specialized molds to ensure a joint width tolerance of ≤2mm; second, elastic sealant is used for filling during on-site installation, and the sealant must have weather resistance from -40℃ to 80℃—Qinglong recommends a combined solution of silicone structural adhesive and foam rods; finally, adjustable metal cover plates are installed at the joint openings, balancing waterproofing and decorative effects. This process has achieved zero leakage and zero cracking records in award-winning projects such as the Dongguan Women and Children's Activity Center.

IV. Full-Chain Service Ensures Implementation of Expansion Joint Design

Leveraging 28 years of industry experience, Qinglong Group has established a full-chain service system from design consultation to after-sales maintenance: during the design phase, BIM technology simulates thermal deformation to optimize joint spacing and width; in production, automated production lines ensure component dimensional accuracy; during construction, 3D laser scanning positioning achieves perfect integration of expansion joints with the building facade. In addition, Qinglong provides warranty service for up to 10 years, regularly inspecting and maintaining the sealing performance of expansion joints to safeguard long-term project safety.

Though seemingly minor, the expansion joint design of UHPC exterior wall profiles directly relates to building safety and aesthetics. As a professional supplier of UHPC/GRC/GRG/GRP materials, Qinglong Group has always maintained an attitude of "meticulousness and the pursuit of excellence," deeply integrating technical standards with engineering practice to provide compliant and economical solutions for designers and owners. To learn more about UHPC component design details, welcome to follow Qinglong Group's technical column, where we will continue to share the professional experience accumulated over 28 years in the industry.