Prefabricated Concrete Assembly House

Prefabricated concrete assembly houses, also known as prefabricated concrete modular houses, are a form of construction where building components are industrially produced and assembled on-site, offering advantages such as shortened construction periods and reduced pollution.

Main Types and Technical Systems

1. Type Classification

   • Panel-based Assembly: Utilizing prefabricated wall panels and floor slabs as core components, connected via bolts or welding. Its advantage lies in expanding indoor usable area, though design flexibility is limited, making it suitable for standardized residential construction.
   • Box-based Assembly: Functional units such as bathrooms and kitchens are prefabricated into independent 'boxes' and assembled on-site. Construction speed increases by 50%-70% compared to traditional methods, but it requires higher transportation and lifting equipment capabilities, suitable for rapid construction projects.
   • Frame-based Assembly: A frame structure is formed using prefabricated beams, columns, and floor slabs, with node concrete poured on-site. It offers strong structural integrity and excellent seismic performance, commonly used in high-rise buildings or public structures.

2. Technical Systems

   • Prefabricated Concrete Structure: Employs reinforced concrete prefabricated components, such as double-layer walls (two concrete slabs connected by welded mesh), which are lightweight yet strong.
   • Steel Structure System: Primarily consists of metal components combined with concrete floor slabs, offering even lighter self-weight and suitable for large-span buildings.

Construction Process and Key Technologies

1. Component Production

   • Concrete components are poured in factories using metal molds, with embedded steel mesh and connectors. Vibrators are used during pouring to eliminate air bubbles, and the surface is smoothed before covering with plastic film and heated curing.
   • Special components like double-layer walls require layered pouring, with space reserved in the middle for insulation material filling.

2. On-site Construction

   • Foundation Treatment: Dig pits approximately 1 meter deep, lay a damp-proof membrane, pour 'discarded concrete' as a base, and install guide steel plates to position prefabricated piles.
   • Component Assembly: Use light cranes to lift and install prefabricated wall panels and floor slabs, securing them with bolts or welding to ensure verticality and levelness.
   • Node Treatment: For frame structures, node concrete between beams and columns is poured on-site to enhance overall integrity.

Development History and Application Status

1. Technological Evolution

   • 1950s: China began applying prefabrication technology, mainly for factories and residences.
   • 1970s: Technical systems such as large-panel structures and box structures were formed.
   • Mid-1980s: Stagnated due to cost and quality issues.
   • 21st century: With rising environmental demands, companies like Vanke developed prefabricated shear wall residential systems, leading to technological resurgence.

2. Policies and Market

   • Regions like Fujian Province have established industrial bases with policy support, reducing construction waste by over 70%.
   • China's prefabricated housing exports have grown significantly, such as the export of movable houses from the Guangzhou Customs area reaching 1.4 billion yuan in the first four months of 2026, a year-on-year increase of 38.1%.

Advantages and Challenges

• Advantages: Construction periods shortened by over 50% (a two-story rough house can be completed in about two weeks), reduced on-site wet operations and dust pollution, and high material utilization rates.
• Challenges: High initial investment costs, the need for early design planning, and strong dependence on transportation and lifting equipment.