There are many types of bricks in the construction field, and they vary in size, shape, properties, and more. Although modern bricks need large equipment and skilled labour for manufacturing, sun-dried bricks stand out distinctively. Here we take a look at what sun-dried bricks are, their applications, pros and cons.
What are Sun-Dried Bricks?
Sun-dried bricks are a special type of brick that is completely eco-friendly and manufactured using natural resources. These types of bricks use the sun’s heat waves to naturally dry the molded clay into bricks instead of burning the bricks in the fire. This is one of the ancient and sustainable practices in the brick manufacturing process and has been carried out for thousands of years.
Manufacturing of Sun-Dried Bricks
- Removing Top Soil: The top layer of the soil is removed to a depth of 200 mm to eliminate loose materials and impurities.
- Unsoiling & Spreading: After removing the impurities, the clay is dug at a depth of 600 mm to 1200 mm from the ground and spread on a leveled surface.
- Cleaning: The extracted clay is cleaned to remove stones, pebbles & other vegetable matter. If impurities are spotted, they are removed using washing and screening.
- Weathering: The cleaned clay is exposed to the weather for a few weeks with alternate wetting, cooling, and drying.
- Blending: In this process fillers such as sand, fly ash, or other straw materials are added and mixed together in the vertical direction until it becomes a blended mixture.
- Tampering of clay: The blended clay mixture is combined with an adequate amount of water and is kneaded with the foot or cattle until it becomes a homogeneous mix with plasticity.
- Moulding into a brick: A wooden or metal mold is used to shape the tampered clay into the shape of a brick/block. The sun-dried bricks typically use hand-molding or ground moulding.
- Drying: After the moulding process, the bricks are kept for drying under the sunlight to naturally remove the moisture for a number of days, weeks or even months depending on the weather conditions, until the brick is completely dry and ready for use.
Materials used for Sun-Dried Bricks
Clay
Clay is the primary material that provides structure and binding properties. Silted clay or weathered clay is best suited for the bricks, as it provides sufficient cohesion and silt content, which offers proper texture, moisture, and plastic properties.
Sand
Sand is used as a filler material in the manufacturing of bricks. It helps reduce shrinkage, increase durability, and helps bricks to maintain shape. This ensures that the bricks do not crack or lose their shape and makes them suitable for load-bearing structures.
Straw
The usage of straws adds more strength to the brick and helps the brick to dry more evenly in the wet mass. The use of straw in bricks acts as a thermal agent, which absorbs moisture and makes it fire resistant.
Water
Water acts as a binding material that combines all the components into a mix. Although it is a significant material, the water needs to be dried out to achieve hardness.
Applications of Sun-Dried Bricks
- Generally used for low-raised buildings up to one floor and other non-engineered structures.
- Suitable for places with hot and dry climatic conditions due to its thermal properties.
- Used for short-term and structures that don’t withstand any weights such as walls, temporary tents, partition walls, and more.
Advantages and Disadvantages of Sun-Dried Bricks
Advantages
- Thermal Insulator: As the bricks are exposed to natural weather conditions, they act as a natural thermal insulator, protecting the building from extremely hot climatic conditions.
- Sustainable: As the bricks are made naturally without the usage of any artificial machines are burning kilns, they are eco-friendly, sustainable, and free from carbon emissions.
- Low cost: This is one of the most low-cost brick material for manufacturing, as it does not require expensive equipment and high-skilled workers.
Disadvantages
- Durability: These bricks are comparatively less durable than the burnt bricks, making them unsuitable for multi-storeyed structures.
- Poor water resistance: These bricks are porous and less water-resistant and are not suitable for extremely humid regions or wet climate conditions.
- High Maintenance: Frequent maintenance is required, as they are subject to damage from multiple external factors including water, weather, and erosion.
- Manufacturing time: The processing time of sun-burnt bricks is comparatively longer than burnt bricks, as it takes weeks or even months to remove the moisture content from the bricks. Since the sun is being the only drying source, climatic conditions could play a major role in the processing of bricks.
Burnt bricks vs Sun-dried bricks
| Burnt Bricks | Sun-dried Bricks |
| These bricks are dried at high temperatures to make them harder and more durable. | These bricks are dried naturally under the sun without any artificial heat. |
| The manufacturing cost is high and uses high energy making it unsustainable. | The manufacturing cost is low compared to burnt bricks and sustainable as the natural process doesn’t need artificial burning. |
| Durability, compressive strength, and weathering capacity are high, making it suitable for extreme conditions. | The durability and strength are low and are not suitable for humid and wet conditions. |
| These bricks are widely used in different types of construction including high-raised residential buildings, commercial structures, and other engineering constructions. | These bricks are suitable only for temporary and low-raised buildings up to G+1 buildings are not suitable for engineered structures. |
| Comparatively requires less maintenance than adobe bricks. | Requires high maintenance as they are vulnerable to erosion, damage, and extreme humid conditions. |
| The manufacturing time is less and are prepared within a few days. | The sun-dried bricks require weeks to months to get prepared, depending upon the weather conditions. |
Conclusion
The Sun-dried bricks are ideal for temporary, decorative, low-load-bearing structures. Since it has great thermal resistance, they can be used for the construction of houses in desert areas, and places with very little or no rainfall, as they could naturally act as an insulator. Although there are several bricks in the industry, sun-dried bricks could be more eco-friendly, more affordable, and could be a great choice for small construction projects and decorations.