AAC Blocks Vs Red Bricks: How to Make the Right Choice!
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Since ancient times bricks are prime building material with utility value for thatched houses as well as for multi-storeyed buildings. However, the demand and supply ratio for bricks cannot be maintained due to the growing population and the subsequent need for housing requirements.
Moreover, to match the demand for bricks means exhausting fertile land. India, and similar developing countries, cannot afford damaging its resources through erosion of fertile land. Plus, the scarcity of skilled labour and the increasing cost of kiln fuel makes it costlier. That’s why the demand and supply ratio for bricks requires an alternative solution for bricks. This has led to the use of concrete blocks as an alternative material.
As my senior colleague once told, “The red colour of brick was so popular in olden days, that when the AAC blocks or even fly ash bricks entered into the market, there was a lot of resistance from people about using it, as it was grey in colour and was made from ‘ash’ , to which it was difficult to reconcile”
Also Read: Brick Flooring: All you Need Know
Red Bricks are common building materials. Red bricks are not only one of the oldest but also the most extensively used building materials worldwide. These building materials are the most popular and leading construction material because it is cheap, locally available, durable and easy to handle and to work with.
AAC blocks are one of the major achievements of the 20th century in the field of construction. It is a revolutionary material offering a unique combination of high durability and strength, low weight and superior ecological ‘green’ features.
AAC Blocks and Red Bricks, both are important building materials for constructing walls. Red bricks & AAC blocks are used in walls as per their properties, availability and cost. Hence, here in we give you a brief comparison between AAC blocks Vs Red bricks to help you make the right and informed choice.
- A Red brick is a block, or a single unit of a ceramic material used in masonry construction, usually stacked together, or laid using various kinds of mortar to hold the bricks together and make a permanent structure.
- Bricks are typically produced in common or standard sizes in bulk quantities.
- AAC Blocks are lightweight building materials cut into masonry blocks or formed as larger planks and panels.
- AAC Block is relatively uniform when compared to other wall units and does not contain coarse aggregate phase.
02. Raw Material
- It is made by a mixture of clay(alumina), sand, Lime, iron oxide and Magnesia.
- Natural soil is used for production of Bricks. Hence, ultimately it will vary depending upon the quality of local soil, i.e. Top soil of Earth’s Crust.
- It is made from the mixture of fly ash, cement, lime, gypsum and an aeration agent. The fly ash used in AAC Blocks production is eco-friendly & Cement is used in very little Quantity. The problem of fly ash utilisation is solved by the use of fly-ash in AAC Block. This was a major problem till day.
01. As a Structural Unit:
Red bricks are strong, hard, durable; therefore these are used as a construction material in different structures such as
02. As an Aesthetic and Finish Surface:
Bricks are used as per its different colours, sizes and orientations to get different surface designs. As an aesthetic material brick can be used
- As Facing Bricks
- Architectural Purposes
- Exposed practice work
- AAC Block can be used to build internal and external walls.
- According to ‘IS 2185(Part3)-1984’ (Specification for Concrete Masonry Units), Autoclaved aerated concrete blocks are, used for both load bearing and non-load bearing internal walls, partition and panel walls, inner leaf of cavity walls or as backing to brick masonry and for external load-bearing walls as well as panel walls in steel or reinforced concrete frame structure, when protected from weather by rendering or by some other adequate treatment.
- Raw material is easily and abundantly available. So, it is economical.
- Red Bricks are low maintenance, permanent, hard and durable building materials.
- Compressive strength of brick is good enough for ordinary construction requirements.
- Different orientations and sizes give different surface textures.
- Demolishing of brick structures is very easy and less time consuming.
- It is reusable and recyclable.
- Highly fire resistant.
- AAC blocks are very easy to handle and ordinary tools are used for cutting.
- AAC blocks are available in large sizes and hence less no. of joints. This ultimately results in faster construction on site and less consumption of cement and also increasing in strength of wall.
- Earthquake forces are proportional to the weight of building and it ultimately reduces the load on buildings, and hence less steel in case of RCC structure.
- AAC blocks are made from an inorganic material which helps to avoid termites, damages or losses.
- Saves steel and concrete due to the reduction in dead weight.
- Increase in floor area due to a reduction in the size of columns and thickness of the wall.
- Easy to transport on upper floors.
- Time-saving in construction.
- AAC blocks have a very low thermal conductivity which keeps interior remain cool in summer and warm in winter.
- AAC blocks reduce interior temperature variation maintaining pleasant and healthy temperature for habitant.
- AAC blocks reduce the energy cost of air-conditioning to a great extent due to its thermal property.
- AAC blocks are appropriate for fire rated application for desired safety.
- One AAC block of size (600 x 200 x 100 mm) is equivalent to 6 bricks hence it reduces 50% of joints resulting in saving of mortar up to 48%. In the case of 150 mm or thicker block masonry, the mortar saving is even more due to the avoidance of vertical joint in conventional brick masonry.
- Minimal wastage of AAC blocks.
- It is environment-friendly and also saves water. Hence it is popularly used as a green product.
- The production cost of AAC Blocks is expensive but on the whole project cost decrease.
- Time consuming construction
- Red Bricks cannot be used in high seismic zones for load bearing structures.
- A red brick absorbs water easily so Efflorescence occurs due to the presence of salt in water.
- Rough surfaces of bricks may cause moulds growth if it is not properly cleaned.
- Continuous use of Red bricks in construction will lead to extensive loss of fertile top soil and hence potential agricultural land.
- Red bricks are heavy in weight so that the structure needs to withstand greater weight, and hence construction cost increases.
- Big damage to environmental and loss of fertile land due to use of clay soil excavation for making of bricks.
- The production cost per unit for AAC Block is higher.
- Plaster sometimes does not stick properly because of its smooth surface. Needs care during production itself, so that surface is not very smooth.
- AAC block also requires a protective finish since the material is porous and would deteriorate if left exposed.
- According to ‘R. Barry’, AAC blocks are usually dull light grey in colour and are not generally considered as being sufficiently attractive to be used as an exposed facing material for buildings.
06. Identification on Site
- Its colour is Red.
- Colour of AAC Block is Grey.
(a) Size Available in Market
Standard modular size:
- 190 x 90 x 90 mm
- 190 x 90 x 40 mm
Standard Non modular size:
- 230 x 110 x 70
- 230 x 110 x 30
These sizes are more popular in india.
- 400-600×100-200×100-300mm. However, it defers from manufacturer to manufacturer.
(b) Variation in Size
- Red Bricks are not accurate in size, varies largely from area to area.
- The AAC Blocks are accurate in size because it is produced by wire cut technology and is a factory product.
(c) Dry Density
- 1600-1720 kg/m3
- 1721-1820 kg/m3
- 1821-1920 kg/m3
- 451-550 Kg/m3
- 551-650 Kg/m3
- 651-750 Kg/m3
- 751-850 Kg/m3
- 851-1000 Kg/m3
- 2.5 – 3.5 Kg
- It will depend on density & size of brick.
- 3 – 4 kg
- It will depend on Density & size of Block.
(e) Compressive Strength
- 30-35 N/mm2
- Strength is defined as a capacity to resist force or pressure.
- 30-35 Kg/cm2
(f) Water Absorption
(g) Fire Resistance
- 8-inch-thick wall can resist fire for up to 2 hours.
- According to ‘Portland Cement Association’, Fire resistance of AAC block is excellent, with eight-inch-thick AAC achieving a four-hour rating (actual performance exceeds that and meets test requirements for up to eight hours). And because it is non-combustible material, it will not burn or give off toxic fumes.
(h) Thermal Conductivity
- 0.6- 1.0 W/mk
- The amount of heat transfer from a specific material is called its thermal conductivity.
- The thermal conductivity of brick is high, and hence heat transfer from brick is more than the AAC block.
- 0.21 – 0.42 W/mk
- Thermal conductivity of block is lower and less heat transfer happens from block.
(i) Moisture Resistance
- Moisture Resistance of Red Brick is Average.
- Moisture resistance will depend on water absorption of the brick and proportion of cement mortar.
- 100/115 mm wall will not have adequate moisture resistance. If poor, it will make walls damp & wet.
- Moisture resistance of AAC block is better than the Red Brick.
- AAC block consists of unconnected micro pores which prevent the capillary transport of moisture over a long distance.
(j) Sound Insulation/Noise Transmission
- Sound insulation is defined as the capacity to reduce sound transmission by the building elements.
- Sound transmission also depends upon the thickness of the wall.
- The brick masonry wall has good sound insulation property due to its dense structure.
- 45 db sound is reduced by 150 mm and 50 db sound is reduced by 230 mm walls
- The AAC block has good sound transmission property due to the presence of air voids.
- 40-45 db sound is reduced for 200 mm thick wall.
- That light weight also gives a high sound reduction for privacy, both from outside noises and from other rooms when used as interior partition walls.
(k) Termite Resistance
- Red bricks are not termite resistant as they are made from clay which is an organic material.
- AAC blocks are insect resistant, inorganic and solid wall construction material.
- AAC blocks do not allow spreading of termites and pests and hence increase the life of the wall.
(a) Labour Output
- The speed of Red Brick work will be slow as compared to the Block work.
- The Speed of work will be double than that of the clay brick work.
(b) Carpet Area
- Less carpet area available compared to the block work.
- More carpet area is available due to less thickness of the block
- Red bricks are used for both load bearing and Non-Load Bearing walls.
- AAC Blocks are recommended for high-rise buildings because it substantially reduces total dead load of the building
(d) Mortar Consumption
- Requires more mortar due to irregular surface & more number of joints.
- Requires less mortar due to flat and even surface & less number of joints.
(e) Speed of Construction
- The speed of construction of the brick masonry wall is slower than the block construction.
- Speedy construction of wall due to the bigger block size, light in weight and less number of joints.
(f) Water Usage During Manufacturing
- Requires more water for curing and hence high amount of electricity bill and labour cost.
- Block is cured by steam and block masonry also requires less curing hence less water is used and there is saving in electricity bill.
(g) Breakage & Utilization
- Negligible breakage almost 100 % utilisation is possible.
- In monsoon, Stock at the site is compulsory which blocks large working area on the site otherwise work will get stopped.
- Readily available at any time & in any season at a short notice, so no storage required.
- Generally present.
- Efflorescence occurs due to presence of salt in water and sand.
- Efflorescence occurs through mortar and water.
(a) Construct a 1 Cum Wall Cost
- 1 cum brick work cost around 2500/- in india.
- 1 cum block work cost around 3500/- in india.
(b) Structural Cost
- No such saving is possible.
- Steel saving up to 15% & Concrete saving up to 7%.
- AAC Blocks reduces the load on foundation due to its light self-weight and saves consumption of steel. Hence reduces the Structural Cost.
10. Environment Impact
(a) Green Product
- Red Brick is not a green product.
- On thecontrary, it is the enemy of green i.e. environment.
- Red Bricks are made from the clay which is naturally available material but it reduces the top fertile soil cover.
- AAC Blocks are made from a non-toxic material which does not harm the environment. Using it reduces the industrial waste, and it also decreases greenhouse gas emissions.
- During the manufacturing process, Waste of the AAC Block is recycled and used again. This waste is made from the cutting process. Hence AAC Blocks are a Green product.
(b) Earthquake Resistance
- Red Bricks have resisted average earthquake forces because the density of brick is more than AAC Block.
- Earthquake forces are proportional to the weight of the building. AAC Blocks reduce the weight of building so it increases the safety against earthquake.
11. Tools Used in Manufacturing Process
- Tools used in manufacturing process of bricks are brick moulds, cutting wire or strike, wooden plates called pallets, and stock boards etc.
- Tools used in manufacturing process of AAC blocks are block making machine, hand operated with and without vibrator and electrically operated with vibrator, block pallets, spades, mortar pans, measuring boxes, compacting rod, trowel, curing pipes etc.
This comparison of AAC blocks vs Red bricks will help you in making precise selection for the walls of your home. Red Bricks are made from the natural soil. If this natural soil is used continuously for construction, time will come when natural resources will be scarce. Due to this reason blocks are used for constructing walls. Using AAC block is very advantageous as it not only conserves the environment; it also saves energy and provides safety to life. But the AAC blocks have some limitations. It is not as widely available as most concrete products, though it can be transported anywhere. If it has to be transported, its light weight is advantageous. Keeping in consideration, the pros and cons of both of these building materials, consumers can opt for a suitable material that’s friendly on their pocket, blends well with the environment, looks aesthetically pleasing to the eyes and has a longer lifespan.