In the ever-growing and advanced construction industry, there are several options for choosing the right bricks. Although there are plenty of options, the calcium silicate bricks, or sand-lime bricks, stand out for their attractive appearances and appealing finishes. These bricks are most commonly used in Australia, Europe, and African countries. The attractive nature of the brick is admired by people in India, and the usage of these bricks for Indian construction is increasing at a rapid phase. As the interest continues to grow, here is everything you need to know about calcium silicate bricks.
What is a Calcium Silicate Brick?
Calcium silicate brick is a special type of brick that uses sand and lime as the main raw materials, which are also called sand-lime bricks. These bricks stand out as one of the indispensable building materials that are used for numerous purposes. They are known for their lightweight, multiple colour options, toughness, longevity, and high resistance to heat.
Physical Properties of Calcium Silicate Bricks
- These bricks have a very sleek and consistent finish that makes them look more attractive compared to other available bricks in the market.
- These bricks are tightly packed, strong, and robust enough to maintain the original shape of the brick.
- These sand lime bricks are compact and can hold loads of high capacity of up to 10 N/mm².
- These bricks are repellent to water and are free from efflorescence when exposed to humid conditions.
- These bricks are refractory to fire and can prevent the structure from other solar heat effects.
- They are adept to sound and can prevent the structure from outside noises, acting as noise-cancelling agents.
- No plastering is required, and mortar usage is reduced.
Applications of Calcium Silicate Brick in Construction
These bricks are known for their resourceful applications in the construction field. They are used in multiple construction works for numerous purposes.
- Residential Construction- These bricks are suitable for residential buildings due to their insulation properties. Using these bricks in residential buildings will keep the structure cool in dry and hot weather conditions.
- Commercial Structures- Using sand-lime bricks in commercial structures has numerous advantages. They can protect the building from heat and can withstand for long periods. These bricks can be used for the construction of walls, partitions, and other ornamental purposes.
- Industries- Sand-lime bricks are mainly used for industries, factories, and warehouses, where fire resistance and high durability are crucial.
- Fire Protection- These bricks have excellent fire-withstanding capacity and can be used as firewalls for places that have a high risk of fire, especially in steel and glass manufacturing units.
- Noise Reduction– As sand-limes possess insulating properties, these bricks can be used in structures like schools, colleges, hospitals, and offices that require a noise-free environment.
- Agricultural buildings- These bricks can be used to build agricultural buildings such as sheds, barns, and storage units to protect cattle, fertilisers, and agricultural utensils from moisture and pests.
- Advanced technologies- Some manufacturers have tested smart technology integration to include sensors for monitoring temperature, humidity, and integrity for better maintenance.
Manufacturing of Calcium Silicate Bricks
Mixing
The right proportion of chosen standard sand, lime, and colouring pigments is mixed with 3-5% water to form a homogenous mixture at the right consistency suitable for molding.
Moulding
The blended mixture is transferred to the mould of the required shape and size. The mixture is then molded using a rotary table by applying a mechanical (hydraulic) press at a variable pressure ranging from 30 to 63 N/mm². This pressurised molding process help the brick to attain the desired shape and required compressive strength.
Curing
The molded bricks are transferred to an autoclave (rounded steel cylinder) with a diameter of 2 meters and length of 20 meters. The molded bricks are steamed inside the autoclave with varying pressures from 0.85 to 1.6 N/mm² at high temperatures for 6 to 12 hours to process the chemical reaction in the bricks. During this process, the silica in sand and calcium in lime react together to form a crystal-like compound named calcium hyposilicate.
After autoclave curing, the sand lime bricks are carefully arranged and tested in the laboratory for shape, colour, and durability before being transported to the construction site.
Materials Used for Manufacturing Calcium Silicate Bricks
- Sand- Calcium silicate bricks consist of 88% to 92% of fine sand.
- Lime- A range of 8 to 12% of calcium silicate bricks consists of lime.
- Water- Clean water of 0.25% is used to bind sand and lime together.
- Colour Pigments- A range of 0.2 to 3% of pigments are added as colouring agents. Some commonly used pigments are:
- Carbon Black (black, grey)
- Iron Oxide (Red, Brown)
- Chromium Oxide (Green)
- Ochre (Yellow)
Pros & Cons of Calcium Silicate Brick
Pros
- Attractive appearance with straight edges, uniform shape, size, colour, and texture.
- No need for plastering.
- Ideal for the construction in clay soils.
- Reduces external noises within the structure.
- Acts as a natural coolant and protects the building from fire and solar effects.
- Reduces the overall cost of construction by 30% – 40% compared to other bricks.
- Highly durable and can be used for permanent structures.
- Wall thickness can be reduced.
Cons
- Requires high-quality and expensive equipment for manufacturing.
- Poor abrasion resistance.
- Easily gets damaged by water.
- Not suitable for building furnaces.
- It cannot withstand high temperatures for a long period.
- It cannot be used for foundations.
Conclusion
In conclusion, calcium silicate bricks or sand lime bricks are excellent brick materials in the advanced construction field. These bricks are highly durable and can withstand extensive use for a very long time. They are resistant to heat and dry climatic conditions, making them one of the most reliable options if maintaining indoor temperature is a key. These bricks are suitable for buildings with a focus on sustainability, as they are energy-efficient, recyclable, generate less waste, and reduce carbon footprint. If you are looking for more environmentally friendly and modernised buildings with aesthetic versatility as key, then you can consider sand lime bricks as an option.