Cement Prefabricated Walls in Brick-Concrete Buildings

Cement prefabricated walls, once used in brick-concrete buildings, are architectural wall structures made primarily of Portland cement and steel reinforcement bars, prefabricated into panel shapes using molds. They are now prohibited from use in conventional brick-concrete construction and are only retained for specific applications.

Structure and Types

Cement prefabricated walls use Portland cement as the base material, with steel reinforcement bars embedded inside to enhance structural strength. They are prefabricated in factories into panel-shaped components. Based on internal structural differences, they are divided into two types: solid and hollow:

• Solid prefabricated walls: These have a dense overall structure and strong load-bearing capacity, but they are heavy, consume more materials, and require higher-capacity lifting equipment during construction.
• Hollow prefabricated walls: These reduce self-weight and material costs by incorporating reserved holes inside while maintaining a certain level of structural strength. They are easier to construct and were more widely used in the early stages.

Specifications

Their standard specifications are limited by transportation and construction conditions, with a maximum span of 4.2 meters, widths primarily of 500mm or 600mm, and common thicknesses of 120mm and 150mm. This design balances structural stability and cost-effectiveness, but the span limitation makes it difficult to meet the needs of large-space buildings.

Early Application Advantages

Before the widespread adoption of cast-in-place technology, cement prefabricated walls significantly shortened on-site construction periods due to their prefabricated production, reducing labor and time costs associated with bricklaying, especially for residential projects with tight schedules. Their modular nature also facilitated standardized construction, promoting the industrialization of building processes.

Defects and Reasons for Elimination

1. Poor thermal insulation: The high thermal conductivity of cement and steel, combined with the insufficient insulation of hollow structures despite weight reduction, leads to significant indoor temperature fluctuations in cold or hot regions, necessitating additional insulation layers.
2. Insufficient structural stability: Panel connections rely on mortar or connectors, which are prone to cracking and water leakage over time due to settlement differences or temperature-induced stress.
3. Weak load-bearing capacity: The limited density and diameter of steel reinforcement bars make these walls vulnerable to cracking or collapse during strong earthquakes or typhoons, offering lower safety compared to cast-in-place structures.

Current Status and Alternative Solutions

Due to the above defects, cement prefabricated walls have been banned by national building codes for use in conventional brick-concrete structures. Cast-in-place slabs, with their superior integrity and earthquake resistance, have become the mainstream choice. However, their fast construction and low cost advantages are still utilized in temporary buildings and simple sheds with low durability requirements, such as post-disaster temporary shelters or on-site temporary offices.