Hot Selling AAC Brick Machinery Manufacturer

Great energy efficiency 

High energy efficiency is one of the determining characteristics of autoclaved aerated concrete. AAC's cellular structure gives it a thermal efficiency 10 times higher than that of aggregate concrete and two to three times better than clay brick. Consequently, buildings made of AAC are warm in winter and cool in summer.

AAC is excellent inherent thermal insulation properties not only reduce the need for space heating and cooling, thereby cutting carbon dioxide emissions and combating climate change, but also make the use of additional insulation materials unnecessary. EU insulation requirements can be met by using AAC alone. By contrast, aggregate concrete, clay brick and calcium silicate masonry units need to be used in combination with insulation products, thereby adding to their cost and environmental impact.

AAC is energy-efficient over its whole life cycle. Its production requires less energy than other construction materials and its light weight saves energy in transportation. A fuller summary of AAC's life cycle impacts can be found in the High Resource Efficiency, Low Environmental Impact fact sheet.

Manufacturers of AAC have been instrumental in developing houses with low or very low energy needs. Currently, a German house is considered to be low-energy if its heating requirements are 25% less than national thermal insulation regulations require.

But AAC manufacturers are already preparing to take energy saving much further by laying the foundations for the construction of so-called passive houses.

Through optimisation of their building shells, solar energy and ventilation systems, passive houses need as little as half as much heat as low energy houses.

FIRE RESISTANCE
Excellent fire resistance 

Autoclaved aerated concrete provides the highest security against fire and meets the most stringent fire safety requirements. Due to its purely mineral composition, AAC is classified as a non-combustible building material. It is both resistant to fire up to 1200°C and, unlike other construction materials, heat-resistant.

AAC can thus be used as a fire wall to prevent fire from spreading, thereby protecting lives and economic assets. In principle a fire wall should last up to four hours but tests have shown that an AAC fire wall just 150 mm thick can resist at least for six hours. In a real blaze, an AAC fire wall even survived intact for 120 hours.

Small wonder, then, that AAC is used in fire safety tests as a building material for kilns to measure the fire resistance properties of other construction products. Or that some insurance companies offer reductions in fire premiums for buildings equipped with AAC fire walls.

In addition to internal fire walls, constructing outer walls of AAC contributes significantly to fire safety since most blazes start outside buildings.

Besides being fire- and heat-resistant, AAC does not give off any smoke or toxic gases, which can endanger human life more than fire itself.

AAC manufacturers make it their business to collaborate closely with researchers, architects, fire departments and insurance companies in order to maximise AAC's contribution  to fire safety.

STRUCTURAL PERFORMANCE

Outstanding structural performance 

Autoclaved aerated concrete is extremely strong and durable despite its light weight. AAC's solidity, which comes from the calcium silicate that encloses its millions of air pores and from the process of curing in a pressurised steam chamber, an autoclave. Its excellent mechanical properties makes it the construction material of choice for earthquake zones.

The product's light weight ensures that the foundations of a building are lightly loaded, yet it is strong enough to bear several floors. It retains its properties for the entire life of a building without ageing. AAC resists wind, rain and storm and does not decay or rot. In general, changing outside temperatures cannot damage AAC. Its very limited shrinkage and thermal expansion prevent the formation of cracks in masonry.

AAC also has excellent resistance to chemicals and pollutants and, due to its alkaline nature, can withstand acid rain.

RESOURCES

High resource efficiency, low environmental impact 

Autoclaved aerated concrete's high resource efficiency gives it low environmental impact in all phases of its life cycle, from processing of raw materials to the disposal of AAC waste.

Raw materials
AAC is made from naturally occurring materials that are found in abundance - lime, fine sand, other siliceous materials, water and a small amount of aluminium powder (manufactured from a by-product of aluminium) - plus cement.

Production
Thanks to continuous efficiency improvements, production of AAC demands relatively small amounts of raw materials per m3 of product, and up to a fifth as much as other construction products. No raw materials are wasted in the production process and all production offcuts are fed back into the production circuit. The small amount of surplus material left over after curing is ground and recovered for other uses.

The manufacture of AAC requires less energy than for all other masonry products, thereby reducing use of fossil fuels and associated emissions of carbon dioxide (CO2). Energy is also saved in the curing process since steam curing is carried out at relatively low temperatures and the hot steam generated in the autoclaves is reused for subsequent batches. Industrial-quality water is used and neither water nor steam are released into the environment. No toxic gases are created in the production process.

Transportation
AAC's light weight also saves energy in transportation. The fact that AAC is up to five times lighter than concrete and two to three times lighter than clay brick leads to significant reductions in CO2 emissions during transport. To reduce the need for transportation, AAC manufacturers apply the principle of producing as near to their consumer market as possible.

Use
AAC's excellent thermal efficiency makes a major contribution to environmental protection by sharply reducing the need for space heating and cooling in buildings (see Great Energy Efficiency fact sheet for further details).

In addition, AAC's easy workability allows accurate cutting that minimises the generation of solid waste during use. Unlike other building materials AAC does not need to be used in combination with insulation products, which increase the environmental impact and cost of construction.

Reuse, recovery and disposal
Throughout the life cycle of AAC, potential waste is reused or recycled wherever possible to minimise final disposal in landfill.

AAC manufacturers have taken on a voluntary commitment to recover separated and sorted AAC waste from construction and demolition sites for recycling and reuse. Where AAC waste is sent to landfill, its environmental impact is minor since it contains no toxic substances.