What Are the Requirements for the Base Wall When Installing UHPC Exterior Wall Panels? Base Wall Requirements and Pre-Treatment Specifications

The installation of UHPC exterior wall panels imposes strict requirements on the flatness, strength, and stability of the base wall. Base quality directly affects installation accuracy and structural safety, so base inspection and pretreatment must be completed in advance to ensure compliance with installation standards. Drawing on years of installation experience, Qinglong explains the core requirements and practical specifications for base walls.

I. Strength and Load-Bearing Capacity Requirements for Base Walls

The base wall must have sufficient strength to bear the weight of UHPC components and external loads. Concrete base: compressive strength must be ≥20MPa, with a solid surface free of looseness and hollowing; if strength is insufficient, reinforcement treatment is required, such as applying a bonding agent or attaching steel mesh. Masonry base: solid bricks or concrete blocks must be used, with compressive strength ≥10MPa and masonry mortar strength ≥M7.5; concrete coping and structural columns must also be provided to enhance stability. Steel structure base: steel keels must use steel of Q235 grade or above, with cross-sectional dimensions determined through structural calculations and keel spacing ≤600mm, ensuring load-bearing capacity ≥2 times the weight of UHPC components. In the Guangxi New Media Center project, Qinglong accurately calculated the load-bearing capacity of the steel structure base to ensure the safe installation of double-curved UHPC panels.

II. Flatness and Verticality Requirements for Base Walls

Flatness and verticality directly affect installation accuracy, and deviations must be strictly controlled. Concrete and masonry base: surface flatness deviation ≤3mm/m and overall verticality deviation ≤5mm; if deviations are too large, cement mortar leveling or grinding is required; when the leveling layer thickness is ≥20mm, steel wire mesh must be installed to prevent cracking. Steel structure base: keel installation flatness deviation ≤2mm/m and verticality deviation ≤3mm/10m, precisely calibrated by adjusting shims; Qinglong uses 3D laser positioning technology to ensure keel installation accuracy meets standards. The base surface must be clean and dry, free of dust, oil stains, and laitance, to avoid affecting the bonding or fixing effect of connectors.

III. Waterproofing and Structural Requirements for Base Walls

Reasonable structural and waterproofing design avoids later leakage risks. Waterproofing treatment: the base wall must be pre-treated with a waterproof coating or waterproof membrane, especially at leakage-prone areas such as windowsills and internal/external corners, where an additional waterproof layer should be added; in the Sanya Yingbin Yihao project, Qinglong adopted double-layer waterproofing for the base to improve waterproofing reliability. Embedded parts: steel plates or anchors must be pre-embedded in the concrete base in advance, with position deviation ≤2mm; embedded parts must undergo anti-corrosion treatment. Expansion joints: the base wall must reserve expansion joints according to the design, with spacing corresponding to the expansion joints of UHPC exterior wall panels, to avoid structural deformation caused by thermal expansion and contraction; conventional expansion joint spacing is 6-8m.

IV. Pretreatment and Acceptance Procedures for Base Walls

Standardized pretreatment and acceptance ensure compliance with installation conditions. Pretreatment process: after the base wall is completed, first conduct strength testing and flatness calibration, then perform waterproofing treatment and embedded part installation, and finally clean surface debris. Acceptance criteria: strength meets standards, flatness and verticality comply with specifications, waterproofing construction is qualified, and embedded parts are accurately positioned; UHPC panel installation may proceed only after acceptance. Special treatment: for old building renovation projects, the original base must be reinforced and repaired, damaged areas removed, and leveling and waterproofing redone; in the auditorium renovation of the American International School of Guangzhou, Qinglong ensured the firm installation of UHPC panels through special base treatment.