AAC Plant

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AAC Plant

AAC Plant

AAC products may be used for both interior and exterior construction. Autoclaved Aerated Concrete, also known as AAC, is a green precast building material present in the global market for over 70 years and is extensively used in residential, commercial and industrial construction. AAC is a well-established building material, which has rapidly gained worldwide market share from conventional building materials because of its superior characteristics. It is used for all walls, external or internal, loadbearing or non-loadbearing walls, basement walls, infill walls to framed structures, party walls, fire break walls, etc.

This eco-friendly building material, made from natural raw materials such as: sand (or fly-ash), cement, lime, gypsum, aluminum powder and water. This mix creates an aerated concrete providing insulation, structure and fire protection in one lightweight product.

AAC Blocks Advantages
- Maximum efficiency and minimal use of resources.
- Larger size blocks leads to faster masonry work.
- Long Lasting, Non Toxic & Fire resistance.
- Excellent eco-balance.
- Outstanding insulation properties.
- Low weight and very easy handling.
- Unsurpassed feasibility.
Applications

Autoclaved aerated concrete (AAC)is the material of choice for building applications, such as residential, commercial, industrial and agricultural buildings, hotels, schools and hospitals, etc., - an excellent building material for all climatic conditions.
AAC Product Properties and Specifications
Autoclaved Aerated Concrete consists of the unique combination of Tobermorite 11A molecules and air pores. Tobermorite 11A is a molecule that, once created, cannot physically decompose through heat, rot, corrosion or other chemical process and thus is very durable.

AAC products are produced using a mix of generally abundant-available raw materials like sand, cement, lime and gypsum. The raw materials are mixed with water, a very small amount of aluminum powder is added, and poured in large moulds.

All in all, the combination of cement, lime, gypsum, sand and most importantly aluminum powder causes the mixer to expand considerably. From beginning to the end, the simplified chemical reactions are as follows :
- Cao + H2O=Ca(OH)2 + 65.2 KJ/mol
- 3Ca(OH)2 + 2 Al + 6 H2O=Ca3(Al(OH)6)2 + 3H2
- 6SiO2 + 5Ca(OH)2=5CaO.6SiO2.5H2O

Step 1
Step 2
Step 3
Step 4

Raw Material Preparation : AAC blocks manufacturing process starts with raw material preparation. List of raw materials and relevant details are mentioned below :

53 Grade Cement
Fly Ash or Sand
Lime Stone Powder
Gypsum

Dosing and Mixing : After raw material preparation, next step of AAC blocks manufacturing process is dosing and mixing. Process of dosing and mixing means the quality of final products. Maintaining ratio of all ingredients as :

FLY ASH OR SAND: LIME:CEMENT: GYPSUM = 69:20:8:3
Aluminum is about 0.08% of total dry materials in the mix
Water ratio = 0.60-0.65

A dosing and mixing unit is used to form the correct mix to produce AAC blocks. Fly ash is pumped into a container. Once the desired weight is poured in, pumping is stopped. Similarly lime powder, cement and gypsum are poured into individual containers using conveyors. Once required amount of each ingredient is filled into their individual containers control system releases all ingredients into mixing drum.

A smaller bowl type structure used for feeding Aluminium powder is also attached as a part of mixing unit. Once the mixture has been churned for set time, it is ready to be poured into moulds using dosing unit. Dosing unit releases this mixture as per set quantities into moulds. Dosing and mixing process is carried out continuously because if there is a gap between charging and discharging of ingredients, residual mixture might start hardening and choke up the entire unit. For AAC blocks manufacturing, entire dosing and mixing operation is completely automated and requires minimum human intervention.

Casting, Rising and Curing : Once mix of raw materials is ready, it poured is in moulds. Moulds can be of various sizes depending upon installed capacity like 4.2m x 1.2m x 0.65m in size. Before casting, moulds are coated with a thin layer of oil in order to ensure that green-cake does not stick to moulds. Usually rising and pre-curing process takes around 60-240 minutes. Rising is dependent on raw material mix and weather conditions. Due to this, pre-curing is also referred as ‘heating room pre-curing’. At end of pre-curing process, green-cake is hard enough to be wire cut as per requirements. After this stage blocks are taken for the DE-moulding and cutting process.

De-moulding and Cutting : Once green cake has achieved cutting strength, it is ready to be remoulded and cut as per requirements. Once a mould is out of pre-curing room, it is lifted by a crane for remoulding operation. While all previous processes like raw material preparation, dosing & mixing and casting are pretty much same across all technologies, remoulding and cutting process vary vastly depending on technology provider. Differences in remoulding and cutting process are also evident from different types of moulds required by different technology provider. Primarily cutting process may be classified as flat-cake and tilt-cake based on how green cake is de-moulded and sent to cutting line.

Mixwell AAC Plant – 50 CBM / day Read More

Mixwell AAC Plant – 100 CBM / day Read More

Mixwell AAC Plant – 150 - 500 CBM / Day Read More

Mixwell AAC Plant – 250 - 500 CBM / Day Read More