Reinforced Concrete Prefabricated Slabs for Houses

Reinforced concrete prefabricated slabs for houses are prefabricated components made of reinforced concrete, primarily used in scenarios such as floor slabs and roof insulation layers. They come in two types: solid and hollow. Existing prefabricated slab houses have issues such as weak earthquake resistance, and cast-in-place concrete and prefabricated buildings are gradually replacing some of their functions.

Definition and Types of Prefabricated Slabs

Reinforced concrete prefabricated slabs are building components made primarily of steel reinforcement and concrete through factory prefabrication processes. Their core structure relies on the steel reinforcement framework to provide load-bearing capacity, with the concrete encasing the steel to form a protective layer. Based on internal structural differences, prefabricated slabs are divided into two types: solid and hollow.

• Solid prefabricated slabs: These have a solid structure throughout, offering strong load-bearing capacity but with a relatively large self-weight, making them suitable for scenarios with high load requirements.
• Hollow prefabricated slabs: By incorporating circular or square holes within the slab, the amount of non-load-bearing concrete is reduced, achieving a lightweight design while also lowering material costs. They are commonly used in residential floor slabs and other areas sensitive to self-weight.

Application Scenarios and Historical Development of Prefabricated Slabs

Prefabricated slabs originated in the early 20th century. In China, residential buildings constructed before 1985 widely adopted this type of structure, primarily for floor slabs and roof insulation layers. With advancements in building technology, cast-in-place concrete (with its on-site pouring and strong overall integrity) and prefabricated buildings (featuring standardized design and high construction efficiency) have gradually replaced traditional prefabricated slab houses as the mainstream. However, prefabricated slabs are still used in non-main structural scenarios such as highway ditch covers and temporary building insulation layers due to their low cost and fast construction speed.

Issues with Existing Prefabricated Slab Houses and Renovation Policies

Existing prefabricated slab houses generally have the following defects:

• Weak earthquake resistance: The connections between prefabricated slabs and the main structure are mostly rigid joints, making them prone to detachment or collapse during earthquakes due to inconsistent deformation.
• Poor sound and thermal insulation: The hollow structure or single-layer slab design results in high sound and heat conduction efficiency, reducing living comfort.
• Limited service life: Problems such as concrete carbonation and steel reinforcement corrosion give them a design life of approximately 30-50 years, significantly shorter than the over 70 years of cast-in-place structures.

To address these issues, China has implemented renovation policies since 2022, focusing on repairing and upgrading prefabricated slab houses by reinforcing connection joints and adding thermal and sound insulation layers. Only buildings that meet the criteria for dangerous houses (such as severe structural damage or insufficient load-bearing capacity) are subject to demolition and reconstruction.

Technological Upgrades of New Prefabricated Components

In the field of prefabricated assembly buildings, prefabricated slab technology continues to evolve:

• Prefabricated reinforced concrete floor slab connection structures: These use high-strength bolts or welding connections to enhance the earthquake resistance of joints.
• Truss-reinforced concrete composite slabs: Composed of a prefabricated base slab and a cast-in-place layer, they combine the advantages of prefabrication and cast-in-place construction, improving construction efficiency and overall structural integrity.
• Large-scale prefabricated slab processes: Through designs such as laying steel reinforcement frameworks, welding steel wire meshes, and embedding lifting rings, combined with processes like self-compacting concrete pouring, flattening machine vibration, and waterproof cloth covering, they ensure component quality and ease of transportation and installation.