What is Autoclaved Aerated Concrete

Introduction

Most autoclaved aerated concrete blocks are mainly made of cement, lime, silica sand, etc. Some ingredients, such as fly ash, are added. The concrete needs to add steel mesh. Then according to the different products, the addition ratio of materials and ingredients are different.

Autoclaved aerated concrete blocks undergo high temperature, high pressure, and steam curing. The product will react to form porous autoclaved aerated concrete slabs/autoclaved aerated concrete blocks. The density of this type of product is smaller than that of ordinary cement. And it has good fire prevention, sound insulation, heat insulation, heat preservation, etc.

The product was first mass-produced in Sweden in the first half of the 20th century and developed in Germany two years later. The product spread to Asia and other continents in the third year after its development in Germany. Due to the development of this product, its related systems have gradually improved. At first, the autoclaved aerated concrete block has two standard terms: one is aerated concrete block, and the other is autoclaved aerated concrete slabs.

Nowadays, autoclaved aerated concrete blocks have many names "NALC, aerated sand, aerated ash, precision block, self-insulating block, etc.". The uneven quality of market products causes these. Relevant departments of the construction industry and some manufacturers withdraw from high-quality products to ensure product quality and safeguard their interests. Some manufacturers emphasize the high quality of a specific product when they promote advanced technology. The products comply with product specifications.

History of AAC

Autoclaved aerated concrete was first developed in the 1880s. The following will tell you the history of the development of autoclaved aerated concrete.

The origin of AAC

In 1880, the researcher Michaelis (Germany) obtained a patent for his steam curing treatment technology invention.

In 1889, Hoffman, a Czech, successfully tested and patented "aerating" carbon dioxide in concrete. Therefore, from a historical point of view, aerated concrete first appeared in the Czech Republic. This man named Hofman obtained a patent for using hydrochloric acid and sodium carbonate to make aerated concrete.

In 1914, Aylsworth and Dyer, both Americans, used aluminum powder and calcium hydroxide to achieve a porous cement mixture and obtained a patent.

In 1919, Grosahe, Germany, made aerated concrete using metal powder as a gas-generating agent.

In 1920, the architect Dr. Johan Eriksson-Sweden took an essential step in developing modern autoclaved aerated concrete. He patented his method of making aerated mixtures with limestone and ground aggregates (Called "lime formula").

In 1923, the architect Dr. Johan Eriksson-Sweden invented the industrial sand aerated concrete (AAC) process at the Royal Institute of Technology in Stockholm, Sweden. Dr. Eriksson has mastered using aluminum powder as a gas generating agent and obtained the patent right. Using aluminum powder to generate gas produces a large amount of gas, and the amount of hydrogen generated is small in water. So the gas generation efficiency is high, the gas generation process is relatively easy to control, and the source of aluminum powder is comprehensive, which provides a large-scale industrial production of aerated concrete. Important conditions. Since then, with the continuous improvement of process technology and equipment, industrial production has become increasingly mature.

In 1929, the world's first industrial sand aerated concrete (AAC) block plant was born and put into production in a small town in Sweden.

In 1937, the production of autoclaved aerated concrete began to go international.

The evolution of AAC

Before World War II, autoclaved aerated concrete was mainly concentrated in the three Nordic countries: Sweden, Norway, and Finland. The Second World War severely hindered the development of autoclaved aerated concrete, stagnating new industries with a sound momentum of development. Due to the global energy shortage, autoclaved aerated concrete with energy-saving advantages Is developed again until World War II. 

In the 1950s, Western Europe, Eastern Europe, and the former Soviet Union successively introduced autoclaved aerated concrete production technology and improved the production process, and many patented technologies emerged.

More than 60 countries have set up factories to produce autoclaved aerated concrete, which is distributed in frigid, temperate, and tropical regions. The leading technologies include Sweden's Ytong technology and Siporex. Technology, Hebel technology from Germany, Unipol technology from Poland, Durox technology from the Netherlands, and Stema technology from Denmark. Germany has become the technical center of autoclaved aerated concrete, and the production of autoclaved aerated concrete worldwide is mainly concentrated in the factories of Hypor and Yitong.

Because autoclaved aerated concrete has excellent thermal insulation and energy-saving properties, its advantages are obvious when used in cold regions. Therefore, the earliest countries that use autoclaved aerated concrete as thermal insulation building materials are mainly concentrated in Northern Europe, Eastern Europe, and Western Europe. It was later developed in Asia and other regions represented by Japan and the former Soviet Union. Poland is a severely cold region with a higher latitude than China's Heilongjiang and higher building energy requirements than Beijing. Therefore, more than 50% of the walls are made of autoclaved aerated concrete; Germany uses autoclaved aerated concrete to produce lightweight block masonry. They built a double-layer fence with an air layer to meet the requirements of heat preservation and energy-saving, and it was also widely used for firewall panels.

After 1950, autoclaved aerated concrete developed rapidly in Japan, and now it is gradually becoming the dominant wall material 72% to 76% of the exterior walls of Japanese buildings use autoclaved aerated concrete slats, of which residential use is the most, accounting for 51% to 56% of the total usage. Because autoclaved aerated concrete has an alkaline environment, the United States also Uses it as a retaining wall behind the target of a weapon shooting range to reduce lead pollution of groundwater and provide environmentally friendly materials for the US military training.

Autoclaved aerated concrete blocks undergo high temperature, high pressure, and steam curing. The product will react to form porous autoclaved aerated concrete slabs/autoclaved aerated concrete blocks. The density of this type of product is smaller than that of ordinary cement. And it has good fire prevention, sound insulation, heat insulation, heat preservation, etc.

The product was first mass-produced in Sweden in the first half of the 20th century and developed in Germany two years later. The product spread to Asia and other continents in the third year after its development in Germany. Due to the development of this product, its related systems have gradually improved. At first, the autoclaved aerated concrete block has two standard terms: one is aerated concrete block, and the other is autoclaved aerated concrete slabs.

Nowadays, autoclaved aerated concrete blocks have many names "NALC, aerated sand, aerated ash, precision block, self-insulating block, etc.". The uneven quality of market products causes these. Relevant departments of the construction industry and some manufacturers withdraw from high-quality products to ensure product quality and safeguard their interests. Some manufacturers emphasize the high quality of a specific product when they promote advanced technology. The products comply with product specifications.