Do different types of bricks require different materials?

Do different types of bricks require different materials? 

The material formulas used to make different types of bricks vary significantly, depending on factors such as the intended use, desired strength, appearance, and production cost.

The following is a detailed introduction to common brick types and their materials:

1. Traditional Clay-Burned Brick

This is the oldest and most traditional type of brick.

Core Materials: Clay and shale.

Production Process: Clay is mixed with water, shaped, and then sintered in a high-temperature kiln (approximately 900°C to 1100°C).

Material Characteristics:

The clay has certain plasticity requirements.

Internal fuels such as pulverized coal and sawdust are sometimes added to aid sintering and save energy.

Product Types: Solid red bricks, porous bricks, hollow bricks, etc.

2. Concrete Blocks (Currently the Most Popular Type)

This is the primary product produced by modern brickmaking machines, and its material formulas vary widely.

Basic Formula:

Binder: Cement (usually ordinary Portland cement), which acts as the "glue" that holds all the materials together. Aggregates:

Coarse aggregate: Stone powder and crushed stone chips (particle size typically under 5mm) provide a skeleton, increasing strength and volume stability.

Fine aggregate: River sand and manufactured sand fill the gaps between the coarse aggregate, making the brick more compact.

Water: Triggers the cement hydration reaction.

Based on this basic formula, the materials and mix ratios are significantly adjusted depending on the brick type:

1. Standard load-bearing blocks (e.g., hollow blocks, solid standard bricks)

Material characteristics: High cement content and well-graded aggregates (coarse and fine mix) ensure high strength and load-bearing capacity.

Typical mix ratio: Cement: Stone powder: Sand ≈ 1:6:2 (by weight). The specific ratio needs to be determined experimentally based on the raw materials and strength requirements.

2. Non-load-bearing blocks (e.g., partition bricks)

Material characteristics: Lightweight or industrial waste materials can be used extensively to reduce cost and weight. Commonly used alternative materials:

Fly ash: A waste product from thermal power plants, it has a certain degree of activity and can partially replace cement, reducing costs and improving workability.

Slag and slag: After grinding, they can also be used as admixtures.

Ceramic aggregate and expanded perlite: Lightweight aggregates used to make lightweight partition panels.

3. Paving Bricks/Permeable Bricks

Material Characteristics: This type of brick has the greatest material differences.

High-strength paving bricks: Utilize high-strength cement and high-quality wear-resistant aggregates (such as quartz sand and granite chips) to ensure wear and compression resistance.

Permeable Bricks: The key formula of these bricks is to reduce the amount of fine aggregate (sand), or even eliminate it altogether. They primarily use coarse aggregate of a single particle size. The particles are encapsulated in cement paste, leaving a large number of interconnected pores, creating permeable channels. The water-cement ratio is also low.

4. Colored Bricks/Facing Bricks

Material Characteristics: In addition to the base concrete material, the key additive is inorganic pigment.

The pigment needs to be evenly added with the other dry ingredients during mixing. To achieve vibrant, long-lasting colors, white cement is often used as a binder, and the cement content is increased to create a finer surface texture and a more authentic color.

III. Other Specialty Bricks

1. Sand-Lime Brick (Silicate Brick)

Core Materials: Lime, Sand.

Production Process: Lime and sand are mixed, pressed into shape, and then cured with high-pressure steam to produce a chemical reaction that creates calcium silicate hydrate, which provides strength. Cement is not contained.

2. Aerated Concrete Blocks

Core Materials: Cement, lime, fly ash/siliceous sand, and aeration agent (aluminum powder).

Production Process: Aluminum powder reacts chemically in the slurry to create bubbles, forming a porous structure. The blocks are then cut and cured with high-pressure steam. They are characterized by being extremely light and offering excellent thermal insulation.

Summary

In short, the materials used to make bricks are by no means static. From traditional pure clay to concrete with cement and aggregate as its core, to environmentally friendly formulations utilizing various industrial waste materials, the evolution of materials reflects technological advancements and rising environmental demands. The basic principles for material selection are:

Meeting performance requirements (strength, durability, permeability, weight, etc.);

Using local materials to control costs;

Complying with environmental policies and encouraging the use of industrial waste.

Thus, before investing in brick-making equipment, it is important to clearly define the target product type and design and find the appropriate raw material formula accordingly.