Prefabricated House Precast Composite Slab

The precast composite slab is an assembled monolithic floor slab formed by the superposition of a precast slab and a cast-in-place reinforced concrete layer, combining structural functions with construction advantages.

Basic Composition and Specifications

The precast composite slab adopts a 'sandwich' structure: The lower layer is a factory-precast concrete thin slab with a thickness of 40 - 60 millimeters. Its surface is treated with roller indentations to enhance the bond with the cast-in-place layer. The upper layer is cast-in-place concrete with a minimum thickness of 90 millimeters, and the specific thickness is adjusted according to the span. Its common spans range from 4 - 6 meters, making it suitable for high-rise buildings and large-span buildings. The precast slab serves as both a structural component and a permanent formwork. Pipes and wires can be laid within the cast-in-place layer, and expanded polystyrene boards can be filled to form a box-shaped cross-section, reducing self-weight and improving sound insulation.

Core Advantages

1. Outstanding Overall Performance
   The rough treatment (such as indentations) of the composite surface increases the overall stiffness by 20% compared to traditional hollow slabs, significantly improving seismic performance. Moreover, the structure has strong continuity and can effectively disperse loads.

2. High Construction Efficiency
   There is no need for formwork erection on-site, and the amount of steel bar binding is reduced. The installation speed is 50% faster than traditional methods, and construction waste is reduced by 60%. In addition, the bottom surface of the precast slab is flat, allowing for direct paint application, further shortening the construction period.

3. Economy and Space Optimization
   Standardized production reduces costs. The floor slab thickness can be compressed to 100 millimeters, increasing the net height by 5 centimeters per floor. By using reserved slots instead of traditional connection methods, the amount of steel bars is reduced, and installation efficiency is improved.

Application Cases and Technological Progress

Several projects in China have applied precast composite slab technology, such as the Beijing Changping Life Valley International Pharmaceutical Smart Manufacturing Park (Phase II), which started construction in March 2026, and the Quzhou Beihang Digital Economy Industrial Park project undertaken by Zhejiang No.1 Construction Group. In the production process, CNC material distribution robots and intelligent formwork layout robots have been introduced to achieve automatic programming for material distribution and formwork generalization. The production cycle has been shortened to 7 minutes, significantly improving efficiency.

Precautions and Costs

1. Joint Treatment: Elastic materials should be used to prevent joint cracking and ensure the overall integrity of the structure.
2. Construction Specifications: The surface of the precast slab should be kept clean and moist. Early-strength agents that can corrode steel bars are prohibited.
3. Price Range: The price per square meter of steel bar truss composite slabs ranges from 56 - 100 yuan, depending on the specifications and region.