What Is the Reserved Width for Expansion Joints in UHPC Exterior Wall Lines and Analysis of Related Construction Key Points

Details determine quality. Expansion joint design provides a dual guarantee of safety and aesthetics for UHPC exterior wall profiles.

In the field of contemporary architectural decoration, UHPC (Ultra-High Performance Concrete), with its ultra-high strength, excellent durability and design freedom, has become the ideal choice for exterior wall profiles in high-end projects such as grand theatres, commercial complexes and landmark buildings. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group is well aware of the critical impact that the scientific setting of the reserved expansion joint width has on project quality. Drawing on Qinglong's hands-on experience from hundreds of projects across the country, this article systematically explains the technical essentials and construction specifications for UHPC exterior wall profile expansion joints.

I. Scientific Setting of the Expansion Joint Width for UHPC Exterior Wall Profiles

Although UHPC material features low shrinkage, it still undergoes slight deformation under the influence of temperature changes, humidity differences, structural settlement and other factors. According to the industry standard "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)" (Plan No. 2024-0232T-JC), which Qinglong participated in formulating, and taking into account the climate characteristics of South China, the reserved width of expansion joints for exterior wall profiles is generally recommended to be 10-15mm. For continuous profiles longer than 6 meters or projects in regions with drastic temperature differences, simulation calculations using BIM technology are required, and the width should be adjusted to 20mm if necessary to ensure sufficient deformation space is reserved.

II. Core Technical Essentials of UHPC Expansion Joint Construction

1. Material Compatibility Selection: Qinglong adopts customized UHPC formulations with a 28-day compressive strength of over 150MPa and an elastic modulus highly matched to the main structure, effectively reducing stress concentration at the joints. Weather-resistant silicone sealant should be selected during construction, with a movement capability of ≥±25%, to ensure no cracking over long-term use.

2. Joint Detail Optimization: Drawing on the experience of Qinglong's Dongguan Women and Children's Activity Center project, the expansion joint nodes adopt a "recessed" design, combined with PE foam rod filling and a two-component sealant caulking process. This structure not only prevents rainwater backflow, but also buffers temperature deformation through the elasticity of the sealant layer, reducing the risk of leakage by 30% compared with traditional flat joint designs.

3. Installation Precision Control: 3D laser scanning technology is used for layout positioning, with errors controlled within ±2mm. Qinglong's original "modular installation method" precasts the profiles in sections, which are then flexibly connected to the main structure on site through stainless steel connectors, ensuring installation efficiency while reserving a buffer allowance for expansion and deformation.

III. Full Life-Cycle Quality Assurance System

As a National High-Tech Enterprise, Qinglong has established a full-process control mechanism from detailed design to after-sales maintenance. In the design phase, Rhino parametric software is used to simulate the deformation of components under extreme temperatures ranging from -30℃ to 70℃; in the production stage, automated concrete placing machines are used for casting to ensure uniform UHPC density; during construction, RFID chips are embedded to achieve quality traceability, and together with a regular inspection system, projects are provided with after-sales support for up to 15 years. This integrated "design-production-construction-maintenance" service model is precisely the core competitiveness that enables Qinglong to establish strategic partnerships with renowned real estate groups such as Poly and China Overseas.

The expansion joint design of UHPC exterior wall profiles may seem minor, but it is in fact a comprehensive embodiment of material properties, structural mechanics and construction techniques. Qinglong Group's 28 years of industry experience lies not only in mastering millimeter-level technical details, but more importantly in translating rigorous engineering logic into practical, implementable solutions. From the translucent concrete project at Century Plaza on Nanjing East Road to overseas projects exported across Southeast Asia, Qinglong has always maintained a "meticulous and excellence-pursuing" attitude, endowing every building with the dual value of safety and aesthetics, and is committed to becoming a world-class leading UHPC/GRC/GRG/GRP manufacturer.