Requirements for Joints of Prefabricated House Slabs

The requirements for joints of prefabricated house slabs vary depending on their type and location and must meet the following specifications:

I. Requirements for Filling Joints of Prefabricated Reinforced Concrete Slabs

1. Cleaning and Moistening: Before filling the joints, thoroughly remove debris and dust from the slab joints and keep them moist to ensure the bonding performance between the concrete and the base layer.
2. Material Selection: Use fine aggregate concrete with a particle size of ≤15mm and a strength grade of no less than C20 to ensure structural load-bearing capacity.
3. Reinforcement Configuration: When the joint width exceeds 40mm, reinforcement shall be installed according to design requirements (usually φ6-φ8@200-300mm) to form a hidden beam structure and prevent cracking at the joints.
4. Pouring Process: The joint filling shall be poured in multiple stages. The initial pouring height shall be 10-20mm below the slab surface, and grooves shall be reserved on the top surface to avoid hollowing of the subsequent leveling layer.
5. Curing Requirements: The filled joint layer shall be cured until its strength reaches ≥C15 (approximately 7 days). Avoid disturbance during this period to ensure full hardening of the concrete before constructing the leveling layer.

II. Requirements for Longitudinal Joints of Prefabricated Floor Slabs

1. Side Joints of Slabs:
   • The joint width shall be reserved at 20-30mm and filled with fine aggregate concrete or special grouting material, with a strength not lower than that of the prefabricated slab itself.
   • Before construction, clean the dust and moisten the base layer to prevent hollowing.
2. End Joints of Slabs:
   • The joint width should be 10-15mm, with an elastic cushion (such as polyethylene foam strips) installed to accommodate temperature deformation and a 2-3mm gap reserved to prevent cracking.
3. Joints at Supports:
   • The joint width shall be consistent with the support width (usually ≥100mm), and additional reinforcement shall be installed to enhance shear resistance.
4. Joints in Special Structures:
   • For expansion joints, seismic joints, etc., the joint width can be 20-50mm according to design requirements, and flexible sealing materials shall be used for treatment.

III. Requirements for Joints of Prefabricated Exterior Walls

1. Location and Construction: The joint location shall correspond to the building facade divisions. Vertical joints shall adopt flush or groove constructions, and horizontal joints shall adopt tongue-and-groove constructions.
2. Drainage and Sealing: If a drainage pipe needs to be installed in the slab joint cavity, a sealing construction shall be added on the inner side to prevent leakage.
3. Fire Protection Requirements: Joints should not cross fire compartments; if they must, the inner side shall be sealed with fire-resistant materials to meet fire protection specifications.

These requirements shall be implemented in conjunction with specific design documents to ensure structural safety and durability.