AAC Blocks vs red bricks – AAC blocks or Autoclaved Aerated Concrete Blocks are lightweight, load-bearing, durable, and an economical product that can be manufactured to meet any requirements. AAC blocks are considered as a green option in place of red bricks because of their enormous potential in terms of insulation, fire-resistant, and thermal resistant properties and are environmentally friendly and superior material compared to concrete, wood, brick, and stone. They can enhance the construction speed, reduce the costs, and unwanted wastage at construction sites.
AAC blocks are superior to conventional red clay bricks in a lot of factors. Considering the impact and necessity of these factors we can easily make a choice.
AAC blocks vs red bricks
AAC blocks are superior to red bricks in a lot of factors relating to quality, speed, workability, cost, and wastage. There is a plentiful to brief on the advantages of AAC blocks over Red bricks, fly ash bricks, Cement Concrete hollow blocks, and CLC blocks.
a) Availability of sizes.
Customisation in size is the most important aspect in deciding the choice of bricks/blocks for a particular structure.
| AAC blocks | Conventional red bricks |
| AAC blocks are available in varied sizes are can be customised for special requirements. | Mostly available in one or two standard sizes. No customisation is possible. |
b) AAC blocks vs red bricks- Technical properties
| AAC Blocks | Conventional bricks |
| AAC blocks are available in 600mm/625mm (length) X 100 – 300 mm (height) x 230/240 mm (width). | Bricks are available in 225 mm (length) x 115 mm (width ) X 75/70 mm (Height). |
| The dimension tolerance of the AAC block is +/-5 mm. | The dimension tolerance of brick is +/- 5 mm to +/-15 mm or more. |
| Density ranges between 500-650 kg/cm3. | Density ranges between 1400-1900 kg/cm3 |
| The Drying shrinkage of AAC blocks is 0.4% which is very low in comparison with Conventional bricks. | The drying shrinkage of bricks is 0.8% which is comparatively high compared with AAC blocks. |
c) AAC blocks vs red bricks – Construction speed
AAC blocks are considered cost-effective and economical in comparison with conventional bricks. The cost-effectiveness of AAC blocks is mostly related to the construction speed.
AAC blocks can enhance construction speed when compared to conventional bricks and are due to some unique characteristics detailed out in the following table.
Let us take a wall of 3mtr x 3 mtr size and 4 inch thickness
| AAC Blocks | Conventional Bricks |
| Area of block = 24 inch x 9 inch (600 mm x 230 mm) = 0.138 sqm Wall area = 3m x 3 m =9 sqm No of blocks = 9 sqm/0.138sqm = 65 blocks (600 mm x 230 mm x 100 mm) size | Area of brick is 9 inch x 3 inch (230 mm x 70 mm) = 0.0161 sqm No of bricks = 9 sqm / 0.0162= 555 bricks (230 x 110 x 70 mm) size |
| Total mortar joints 85 rmt (approx) | Total mortar joints 170 rmt for 4 inch wall & 240-250 rmt for 9 inch wall |
| Weight of an AAC block (9 inch) 16-17 kg for a 9 inch thick block | Weigh of brick = 3-3.5 kg (approx) |
| 1 no 9 inch block = 14-15 bricks | Bricks are heavy |
From the above comparisons, it is clear that the AAC blocks are lightweight and covers more area than bricks. Brick masonry got 3-4 times higher mortar joints and around 14-15 bricks constitute an AAC block. That is why Brick masonry is very slow.
AAC blocks are big, got fewer joints, and can be completed very fast.
Factors influencing construction speed
| AAC blocks are factory-made and posses dimensional accuracy. They are easy to place and plumb. | Red bricks are locally made and are irregular with less dimensional accuracy. Bricks are very difficult to place, level, and plumb. |
| AAC block got fewer joints and hence construction speed is high. | Red Brick got a larger number of joints (4 times) in comparison with AAC blocks and hence construction speed is drastically reduced. |
| AAC blocks cover larger area | Bricks cover less area |
| AAC blocks can even be placed with semiskilled workers due to there dimensional accuracy and shape. | Bricks work can be done with the help of a skilled mason only, due to the inaccuracy and shape issues. |
| AAC blocks mostly use block adhesive for bonding and are available in ready mix packs. The thickness of mortar joints ranges between 3-5 mm. | Brickwork is done by site mixed mortar and has to be a minimum of 10 mm. The mortar thickness is high in the case of brickwork. |
d) Savings in labour
Pre curing and post curing labour
| AAC blocks do not require any pre-curing. AAC block masonry joints are air-cured and need not require any curing. Infrastructure and labour involved in the curing process can be eliminated. | Bricks have to be soaked in water before using it in works. Moreover, 7-day curing has to be done on brickwork. This requires setting up of curing infrastructure, and tabor involvement. |
Labour saving in mortar mixing
| AAC blocks use ready-mix bonding adhesive as jointing material. They are available in 25-30 kg packs and to mix with water before use. | Brickwork uses site mix mortar that involves handling, mixing, and conveying of raw materials, and mortar. |
| This can save substantial tabor cost incurred for mortar mixing and conveying. | Extra tabor cost involvement for mortar mixing and conveying. |
Conveying and re-handling labour
| AAC blocks are supplied in pellets and can be easily lifted and conveyed to the work spots using cranes and tower cranes directly from the trucks. | Bricks are supplied in loose and are unloaded & conveyed manually to different places. They have to be filled in buckets before lifting to heights and involves lots of labour. |
| Saves labour involvement in unloading, conveying, and lifting. Less handling generates zero wastage. | Bricks shifting and conveying involves a lot of labour and generates a huge amount of wastage. |
AAC block work rates are comparably less than brickwork due to the saving involved in the labour part. The rate per cum of AAC blocks will be around INR – 650/- to -750 /- per cum whereas brickwork is around INR 1400-1500/- per cum.
e) Material saving
Saving in mortar
AAC blocks got fewer mortar joints of 3-5 mm thickness whereas brick masonry generates 3-4 times higher number of joints of 12 mm thickness. This can save substantially in terms of jointing material.
| ANALYSIS OF MORTAR FOR RICKWORK | |||||
| 1 CUM Brick work = 0.35 to 0.4 cum mortar | |||||
| Sand cost (Rs.2500/- per cum) | 0.35 | x | 2500 | .= | 875 |
| cement | 1.3 | x | 300 | .= | 390 |
| total cost per cum of brick work | INR | 1265/- |
| ANALYSIS OF BLOCK ADHESIVE |
| 1 CUM block work = 30 kg of block adhesive |
| Rate per kg = Rs. 12-15 per kg |
| Cost for 30 kg = around INR-400/-per cum |
Block adhesive cost 400/- per cum whereas mortar cost is around Rs. 1250/- per cum.
Saving in plastering
AAC blocks are dimensionally accurate and both faces of the block-work look even without any undulations. The undulations can be levelled by providing a minimum plastering thickness of 10 mm inside and 12-15 mm outside. AAC blocks can even be painted by directly applying putty/Gypsum plaster over it.
Brickwork has a fair face and unfair face. For covering up of undulations a 12 mm plastering thickness is required for the fair face whereas a minimum 18 mm thick is required for an unfair face.
There are also other value added benefits of AAC blocks which points out AAC blocks as a superior fire resistant, termite resistant, thermal resistant and green building material . Please read ADVANTAGES OF AAC BLOCKS.
vin civilworld 