Prefabricated Concrete Slabs in House Construction

Prefabricated concrete slabs used in house construction were common concrete prefabricated components in the early 20th century, primarily used in scenarios such as floor slabs and roof insulation layers. They offered advantages like shortened construction periods and reduced costs, but had limitations such as weak earthquake resistance and poor sound and heat insulation. In modern architecture, they have gradually been replaced by cast-in-place concrete and prefabricated buildings, although the technology continues to iterate and upgrade.

Definition and Manufacturing Process of Prefabricated Slabs

Prefabricated slabs are concrete components produced through standardized processes in prefabrication yards. Their core manufacturing processes include:

1. Model Making: Hollow models are nailed together using wooden planks, with steel reinforcement skeletons arranged inside to enhance structural strength;
2. Concrete Pouring: Cement is poured into the hollow parts of the models. After solidification, the wooden planks are knocked off to form finished products;
3. Type Differentiation: They are divided into solid and hollow types. The hollow structure achieves lightweighting by reducing non-load-bearing concrete while maintaining load-bearing capacity.

Applications and Limitations of Traditional Prefabricated Slabs

• Application Scenarios:
  • Early on, they were widely used in residential floor slabs, roof insulation layers, and infrastructure such as highway ditch covers;
  • Among residential buildings constructed in China before 1985, prefabricated slab structures accounted for a high proportion and were the mainstream solution for rapid construction at that time.
• Advantages:
  • Short Construction Period: After being prefabricated in factories, they can be directly installed, reducing on-site construction time;
  • Low Cost: Standardized production reduces material waste and labor costs.
• Limitations:
  • Weak Earthquake Resistance: Their overall integrity is poor, making them prone to fracture or displacement during earthquakes;
  • Poor Sound and Heat Insulation: The hollow structure leads to high efficiency in sound and heat conduction;
  • Limited Lifespan: Their designed service life is approximately 30-50 years, and they require repair or replacement after aging.

Replacement and Upgrades in Modern Architecture

• Replacement Technologies:
  • Cast-in-Place Concrete: Forms an integral structure through on-site pouring, improving earthquake resistance and durability;
  • Prefabricated Buildings: Adopt modular prefabricated components (such as steel-concrete composite modules). The construction period is shortened by 30% compared to traditional methods, and earthquake resistance is enhanced through integral pouring.
• Technological Iterations:
  • Prestressing Process: Uses the "pre-tensioning method" to combine prestressed steel bars with concrete, improving tensile strength;
  • Lightweight Design: Some products adopt hollow structures or foam filling to reduce self-weight and meet specific needs (such as heat insulation);
  • Material Diversification: Derivatives such as steel structures and wooden prefabricated slabs have emerged to adapt to different architectural scenarios.

Policy and Market Status

• Renovation Policies: Since 2022, China has focused on repairing and renovating prefabricated slab buildings, only demolishing those that meet the criteria for dangerous buildings;
• Export Advantages: Chinese enterprises have a comparative advantage in the fields of steel structures and concrete prefabricated components, with significant growth in related product exports, reflecting the maturity of the technology and enhanced international competitiveness.