What Is the Connection Treatment Solution for UHPC Exterior Walls and Door and Window Openings? Connection Treatment Specifications and Waterproofing Assurance

The joints between UHPC exterior walls and door/window openings are high-risk areas for water leakage and are prone to cracking due to thermal expansion and contraction. A refined jointing solution is required that balances waterproof sealing with deformation adaptability to ensure secure and aesthetically pleasing connections. Drawing on project experience, Qinglong analyzes the core treatment solutions and practical key points.

I. Analysis of Core Technical Difficulties at Joint Areas

Due to material differences and structural complexity, joint areas are prone to multiple problems. Material differences cause sealing difficulties: UHPC and door/window frames (metal or plastic) have different thermal expansion coefficients, resulting in large differences in thermal expansion and contraction deformation, which easily causes sealant cracking. Structural stress concentration: the corners of door/window openings bear complex forces and are prone to cracking from building settlement or temperature deformation. Weak waterproofing: door/window openings are areas where rainwater easily accumulates, and if improperly sealed, rainwater can penetrate indoors. In the Sanya Yingbin No.1 project, Qinglong found that multiple leakage issues originated from improper joint treatment.

II. Early-Stage Design Optimization for Joint Areas

Scientific design is the foundation of joint quality, and risks must be mitigated in advance. Opening dimension allowance: door/window opening dimensions should be 20-30mm larger than the door/window frame to reserve sufficient adjustment and sealing space, while ensuring opening verticality deviation ≤2mm/m and flatness deviation ≤3mm/m. UHPC panel lapping design: UHPC panels at door/window openings adopt an "outer-over-inner" lapping method to prevent rainwater from penetrating along joints; outer panels must extend at least 50mm beyond the outer side of the door/window frame. Corner reinforcement design: UHPC reinforcement corner pieces are installed at the corners of door/window openings to enhance structural stability and reduce cracking risk; Qinglong uses precast reinforcement corner pieces to improve corner joint strength.

III. Construction Treatment Process for Joint Areas

Standardized construction procedures ensure secure joints and reliable waterproofing. Substrate treatment: clean the UHPC opening edges and door/window frame surfaces, removing dust and oil stains, and roughen the UHPC surface to enhance sealant adhesion. Door/window frame installation: adjust the frame position to ensure level and plumb, secure it with dedicated connectors spaced ≤600mm apart, with fixing points avoiding corner areas. Gap filling: reserve a 10-15mm gap between the door/window frame and the UHPC opening, first fill it with closed-cell foam backer rods, then apply high-modulus silicone weather-resistant sealant, ensuring full filling without air bubbles. Additional waterproofing layer: install metal edge trim or waterproof membrane additional layers on the outer side of the opening to form a double waterproof barrier. In the Guangzhou Dongzhu Shangdu project, Qinglong ensured leak-free joint areas through double waterproofing.

IV. Specialized Joint Solutions for Different Door and Window Types

Customized differentiated jointing strategies for different door and window types. Aluminum alloy doors and windows: use stainless steel connectors between the frame and UHPC, with highly weather-resistant silicone sealant to avoid electrochemical corrosion. Plastic doors and windows: due to their larger thermal expansion coefficient, low-modulus sealant is required, with larger deformation space reserved (gap width 15-20mm). Sliding doors and windows: focus on strengthening waterproofing at the track areas, installing drainage holes and water stop strips to prevent rainwater from seeping in through the tracks. Rotating doors and windows: add sealing strips between the frame and the door leaf, and use curved UHPC panels for transition on the outer side of the opening to reduce rainwater retention. Qinglong provides specialized joint solutions for different door and window types to ensure compatibility.