Concrete small hollow blocks (abbreviated as concrete small blocks) are made from ordinary concrete materials such as cement, sand, and stone. Their hollow ratio is 25%~50%, and the commonly used concrete block shape is shown in the figure on the right. Concrete small hollow blocks are suitable for building walls in areas with seismic design intensities of 8 degrees and below, including high-rise and large-span buildings. They can also be used for municipal facilities such as fences, retaining walls, bridges, and flower beds, with a very wide range of applications.

1. Concept:

Concrete small hollow blocks are block materials made with cement as the cementitious material, adding sand and stone as coarse and fine aggregates, through measured batching, water mixing, vibration and pressure molding, and curing, achieving a certain hollow ratio.

2. Specifications

Other specifications and sizes can be negotiated between the supplier and the buyer.

3. Strength Grade and Quality Grade

Strength grade: Divided into nine strength grades based on compressive strength: MU5, MU7.5, MU10, MU15, MU20, MU25, MU30, MU35, MU40; based on dimensional deviations and appearance quality, they are divided into three quality grades: superior grade (A), first grade (B), and qualified grade (C).

4. Usage Precautions:

① When small blocks are naturally cured, they must be cured for 28 days before use;

② The relative moisture content of small blocks at the time of leaving the factory must be strictly controlled within the standard specified range;

③ When small blocks are stacked at the construction site, rain protection measures must be taken;

④ Before pouring, small blocks are not allowed to be pre-wetted with water.

Advantages: Lightweight, good thermal performance, good seismic performance, convenient masonry, good wall flatness, high construction efficiency, etc. They can not only be used for non-load-bearing walls but also for load-bearing walls of multi-story buildings with higher strength grades. They can make full use of China's various abundant natural lightweight aggregate resources and some industrial waste residues as raw materials, which has good social and economic benefits for reducing block production costs and reducing environmental pollution.

Weaknesses: The blocks are relatively heavy, prone to shrinkage deformation, easily damaged, inconvenient for cutting and processing, etc. If not handled properly, the masonry is prone to quality problems such as cracking, water leakage, and reduced manual performance.

Suitable for block houses in general industrial and civil buildings, especially for load-bearing walls of multi-story buildings and infill walls of frame structures.

Product quality is implemented according to GB/T8239-2014 "Ordinary Concrete Small Blocks".

Architectural design and construction are implemented according to Zhejiang G16-91 "Concrete Small Hollow Block Building Structure" structural standard atlas and JGJ/T 14-2011 "Technical Specification for Concrete Small Hollow Block Buildings".

According to strength grade

Divided into load-bearing blocks and non-load-bearing blocks. The strength grade of load-bearing blocks is generally above MU7.5, and the strength grade of non-load-bearing blocks is generally below 5.0.^[1]

According to void shape

Divided into square-hole blocks and round-hole blocks.

According to the arrangement of voids

Divided into single-row hole blocks, double-row hole blocks, and multi-row hole blocks.

According to aggregate

Divided into ordinary concrete small hollow blocks and lightweight aggregate small hollow blocks