What is AAC Blocks?
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 are lightweight and compared to the red bricks AAC blocks are three times lighter.
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.Benefits
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 lightweight (20% of the heaviness of cement) and warm properties. Aluminum 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 offer ultimate workability, flexibility and durability. Its main ingredients include sand, water, quicklime, cement and gypsum. The chemical reaction due to the aluminum paste provides AAC with 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 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 aluminum 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.
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 consists of the inorganic material in its constitution that helps to prevent/avoid termites, damages or losses.
Sound Proof
The porous structure of the AAC blocks results in 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 auditoriums, hotels, hospitals, studios, etc.
Earthquake Resistant
The lightweight property of the AAC blocks results in the 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 is 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 in reduced time-to-finish.
Long-Lasting
AAC blocks are highly superior in terms of strength. A 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 in a great reduction of deadweight. Further, the reduced deadweight results in the reduction of the use of cement and steel which helps greatly in cost savings.
Versatile
AAC Blocks have an attractive appearance and are 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 harbor 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 which is characterized by "macro" pores. Macro pores are small air bubbles evenly distributed throughout the material. Therefore, the absorption of water into the AAC material is minimal.
Environment Friendly
AAC is a non-toxic product which 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 lightweight 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 the economical application of a variety of finishing systems. Internal walls can be finished by direct P.O.P., thus eliminating the need for plastering.
Technical Specification
Comparison Between Brick and AAC Block
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