AAC BLOCK kya hote hai

 

What is AAC Blocks?

Origins

The Autoclaved Aerated Concrete (AAC) material was developed in 1924 in Sweden. It has become one of the most used building materials in Europe and is rapidly growing in many other countries around the world

AAC is produced from the common materials, lime, sand, cement and water, and a small amount of rising agent. After mixing and moulding, it is then autoclaved under heat and pressure to create its unique properties. AAC has excellent thermal insulation and acoustic absorption properties. AAC is fire and pest resistant, and is economically and environmentally superior to the more traditional structural building materials such as concrete, wood, brick and stone.

At the point when AAC is blended and cast in structures, a few compound responses occur that give AAC its light weight (20% of the heaviness of cement) and warm properties. Aluminium powder responds with calcium hydroxide and water to frame hydrogen. The hydrogen gas froths and copies the volume of the crude blend making gas rises to 3mm (⅛ inch) in distance across. Toward the end of the frothing procedure, the hydrogen escapes into the air and is supplanted via air.

AAC Blocks is a unique and excellent type of building material due to its superheat, fire and sound resistance, AAC blocks are lightweight and offers ultimate workability, flexibility and durability. Its main ingredients include sand, water, quicklime, cement and gypsum. The chemical reaction due to the aluminium paste provides AAC its distinct porous structure, lightness, and insulation properties, completely different compared to other lightweight concrete materials.

When the forms are removed from the material, it is solid but still soft. It is then cut into either blocks or panels, and placed in an autoclave chamber for 12 hours. During this steam pressure, hardening process, when the temperature reaches 190° Celsius (374° Fahrenheit) and the pressure reaches 8 to 12 bars, quartz sand reacts with calcium hydroxide to form calcium silicate hydrate, which gives AAC its high strength and other unique properties. Because of the relatively low temperature used AAC blocks are not considered fired brick, but a lightweight concrete masonry unit. After the autoclaving process, the material is ready for immediate use on the construction site. Depending on its density, up to 80% of the volume of an AAC block is air. AAC's low density also accounts for its low structural compression strength. It can carry loads of up to 8 MPa (1,160 PSI), approximately 50% of the compressive strength of regular concrete.

AAC offers incredible opportunities to increase building quality and at the same time reduce costs at the construction site.

AAC is produced out of a mix of quartz sand and/or pulverized fly ash (PFA), lime, cement, gypsum, water and aluminium and is hardened by steam-curing in autoclaves. As a result of its excellent properties, AAC is used in many building constructions, for example in residential homes, commercial and industrial buildings, schools, hospitals, hotels and many other applications. AAC contains 60% to 85% air by volume.

AAC Blocks Benefits

Fire Resistant

Depending upon the thickness of the Autoclaved Aerated Concrete (AAC) Blocks, they offer fire resistance from 2 hours up to 6 hours. These blocks are highly suitable for the areas where fire safety is of great priority.

Pest Resistant

Autoclaved Aerated Concrete (AAC) Block consist of the inorganic material in its constitution that helps preventing/avoiding termites, damages or losses.

Sound Proof

The porous structure of the AAC blocks results into enhanced sound absorption. The Sound Transmission Class (STC) rating of the AAC blocks up to 45 db. Thus, AAC blocks have been the most ideal material for the construction of walls in auditorium, hotels, hospitals, studios, etc.

Earthquake Resistant

The light weight property of the AAC blocks results into higher steadiness of the AAC blocks in the structure of the buildings. As the impact of the earthquake is directly proportional to the weight of the building, the building constructed using AAC blocks are more reliable and safer.

Faster Construction

As the AAC block is very easy to handle, manipulate and use ordinary tools for cutting the wood such as the drill, band saws, etc. could be easily used to cut and align the AAC. Moreover, the AAC blocks come with larger sizes and fewer joints. This ultimately results in faster construction work as the installation time is significantly reduced due to fewer amounts of blocks and the masonry amount involved is also lowered resulting into reduced time-to-finish.

Long Lasting

AAC blocks are highly superior in terms of the strength. Higher level of strength of these blocks gives higher stability to the structure of the building. AAC is manufactured from non-biodegradable materials, which neither rot nor attract mould, keeping interiors clean and durable.

Cost Saving

AAC block weighs almost around 80% less as compared to the conventional red brick ultimately resulting into great reduction of deadweight. Further, the reduced deadweight results into reduction of the use of cement and steel which helps great in cost savings.

Versatile

AAC Blocks have an attractive appearance and is readily adaptable to any style of architecture. Almost any design can be achieved with AAC.

Non-toxic

Autoclaved Aerated Concrete products do not contain any toxic gas substances. The product does not harbour or encourage vermin.

Thermal Insulation

AAC block has exceptional thermal insulating qualities. The thermal conductivity of the AAC blocks helps to maintain the inner temperature to be warm during the winters and cool during the summers which ultimately leads to savings in air conditioning load and consequently enhanced energy efficiency.

Moisture Resistance

Moisture from both external and internal sources can cause damage to buildings, therefore, moisture protection is a primary consideration.

External moisture sources include rain and water from the soil. Internal moisture, usually in the form of humidity, can cause condensation on the surface of the walls as well as condensation inside the wall itself.

AAC has a very porous structure that is characterized by "macro" pores. Macro pores are small air bubbles evenly distributed throughout the material. Therefore, absorption of water into the AAC material is minimal.

Environment Friendly

AAC is a non-toxic product that does not pollute the air, land or water. During the manufacturing process, waste from the cutting process is recycled back with raw materials and used again. During construction, there is virtually no waste generated. The energy consumed in the production process is only a fraction compared to the production of other materials. The manufacturing process emits no pollutants and creates no by-products or toxic waste products. AAC is manufactured from natural raw materials. The finished product is thrice the volume of the raw materials used, making it extremely resource-efficient and environmentally friendly.

Lightweight

One of the biggest features of AAC blocks is its lightweight. These blocks possess a cellular structure created during the manufacturing process. Millions of tiny air cells impart AAC blocks very light weight structure. The density of these lightweight blocks usually ranges between 550 – 650 kg/m³ making them lighter than water.

Perfect Size and Shape

The process of manufacturing AAC Blocks ensures constant and consistent dimensions. Factory finished blocks provide a uniform base for economical application of a variety of finishing systems. Internal walls can be finished by direct P.O.P., thus eliminating the need of plastering.

High Compressive Strength

The block has an average compressive strength of (3-4.5) N/mm³ which is superior to most types of light weight blocks, 25% stronger than other products of the same density.

High Resistance to Water Penetration

The AAC products, because of their cellular and discontinuous micro structure are superior to the normal clay brick in resistance of water penetrability and thus the external surface of AAC walls provides superior resistance to moisture penetration than the traditional clay bricks

Autoclaved Aerated Concrete is a Lightweight, Load-bearing, High-insulating, Durable building product, which is produced in a wide range of sizes and strengths. AAC Blocks is lightweight and compare to the red bricks AAC blocks are three times lighter.

SOURCE /http://www.ecogreenproducts.in/