Pouring Specifications for Prefabricated Slab Houses

The pouring specifications for prefabricated slab houses cover key aspects such as materials, installation, cast-in-place layers, construction details, and acceptance inspections. The following points must be strictly adhered to:

Material Selection Prefabricated slabs must be qualified products that meet national standards, with their load-bearing capacity, crack resistance, and durability satisfying design requirements. Reinforcing steel must be prestressed, and the concrete strength grade should not be lower than C30. Auxiliary materials such as reinforcing steel, cement, and sand and gravel must also comply with relevant standards to ensure the overall structural safety.

Prefabricated Slab Installation and Connection

1. Placement Requirements: When placing prefabricated slabs on concrete members (such as ring beams), the support length should be ≥80mm; when placing them on walls, the support length should be ≥100mm.
2. Gap Treatment: A gap of 20-40mm should be left between two slabs. After installation, the lower ends of both slab ends should be bedded with mortar to enhance adhesion.
3. Connection Methods: Welding, bolt connection, or reserved reinforcing bar overlapping should be used to ensure a firm connection. The joint width should be ≤20mm and filled with special joint-filling mortar. The reinforcing bars in the cast-in-place layer should span the joint continuously.

Cast-in-Place Layer Pouring

1. Thickness and Reinforcing Bars: The thickness of the cast-in-place layer is usually 70mm. Bidirectional reinforcing bar meshes should be tied before pouring concrete to form an integrated load-bearing system.
2. Surface Treatment: Before pouring, the surface of the prefabricated slabs should be roughened (roughness ≥4mm) and moistened without ponding. Micro-expanding fine aggregate concrete is preferred.
3. Protective Layer Requirements: The thickness of the protective layer for the reinforcing bars in the cast-in-place layer should comply with specifications, such as 20±3mm, to prevent reinforcing bar corrosion from affecting structural durability.

Construction Details and Quality Control

1. Temporary Supports: Temporary supports should be set up during installation to ensure the stability of the prefabricated slabs. After installation, they should be secured.
2. Anchorage Length: The length of the reinforcing bars extending into the beam should be ≥5d (d is the diameter of the reinforcing bar), and the ends must pass the beam's centerline to ensure anchorage effectiveness.
3. Vibration and Form Removal: During pouring, the concrete should be vibrated densely to avoid voids or cracks. When removing forms, the strength of the cast-in-place layer should be ≥15MPa to prevent structural damage.

Acceptance Standards

1. Dimensional Deviations: The allowable deviation for slab length is ±5mm, and for slab width, it is ±3mm, to ensure the dimensional accuracy of the components.
2. Flatness: A 2m straightedge should be used for inspection, with flatness ≤3mm to ensure surface quality.
3. Overall Inspection: During acceptance, the quality of the prefabricated slabs, installation positions, and connection conditions should be checked to ensure they comply with design requirements and that the structure is safe and reliable.