Concrete Grade of Prefabricated Houses

The concrete grade of prefabricated houses varies depending on the specific type and purpose, with common grade ranges from C25 to C50.

Concrete Grade of Prefabricated Floor Slabs

According to the national standard 'Code for Design of Concrete Structures' (GB 50010-2010, 2015 edition), commonly used concrete strength grades for prefabricated floor slabs include C25, C30, C35, C40, C45, and C50, among others.

• Ordinary residential and office buildings: C30 is the most common grade, capable of meeting the load-bearing requirements of general building structures while balancing economy and construction convenience.
• Industrial plants, underground garages, or floor slabs with heavy loads: Concrete grades of C40 or higher may be required to handle larger loads or special usage environments, such as equipment vibration and vehicle rolling.

Concrete Grade of Prefabricated Concrete Composite Slabs

Prefabricated concrete composite slabs consist of a prefabricated layer and a cast-in-place layer, with different concrete grades for each:

• Prefabricated layer: The grade is typically C30-C50, with the specific choice depending on the building type and structural requirements. For example, C30 is suitable for ordinary residential or low-load scenarios, while C40-C50 is used for high-rise buildings or large-span structures due to their stronger crack resistance and load-bearing capacity, effectively reducing structural deformation and crack risks.
• Cast-in-place layer: The grade is generally C25-C30, primarily serving to level, enhance overall integrity, and connect the prefabricated layer, with relatively lower grade requirements.

Core Principles for Grade Selection

The selection of concrete grades requires comprehensive consideration of the following factors:

1. Structural load: The larger the load, the higher the required grade. For example, the floor slabs of industrial plants need to bear heavy equipment, with grades typically not lower than C40.
2. Usage environment: Humid, corrosive environments, or frequent temperature changes may accelerate concrete deterioration, necessitating an appropriate increase in grade or the addition of admixtures.
3. Economy: Higher-grade concrete is more costly, so design optimization is necessary to meet safety requirements while avoiding excessive investment.

Summary: The concrete grade of prefabricated houses should be determined based on the specific type (e.g., floor slabs, composite slabs) and purpose (e.g., residential, industrial plants), with common grade ranges from C25 to C50. Design should strictly adhere to standards and make comprehensive decisions based on structural requirements, environmental conditions, and economy.