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What is aerated concrete block?

Time:2021-11-03     View:     Share:

Welcome to beautiful Villa small class! Do you know what aerated concrete blocks are? Don't worry if you don't know. Let's Get some new knowledge.


1. Basic Concepts


Aerated concrete block is a new building material with light weight, porous, heat insulation, good fire resistance, nailing, sawing, gouging and seismic resistance. As early as in the early 1930s, China began to produce this product, and widely used in high-rise frame structure buildings. It is a kind of excellent new building material, and has the advantages of environmental protection.

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Two, product advantages


1. Light weight


Aerated concrete blocks generally have a mass of 500-700 kg/cubic meter, which is only equivalent to 1/4-1/3 of clay bricks and lime-sand bricks and 1/5 of ordinary concrete. It is a lighter kind of concrete and is suitable for filling walls of high-rise buildings and load-bearing walls of low-rise buildings. Using this material, the dead weight of the entire building can be reduced by more than 40% compared with that of ordinary brick and concrete structures. As the weight of the building is reduced, the earthquake damage is small, so the earthquake resistance of the building is greatly improved.


2. Heat insulation


The thermal conductivity of aerated concrete is generally 0. 11-0. 18W/m·K, only for the clay brick and lime sand brick 1/4-1/5, (the thermal conductivity of the clay brick is 0. 4-0. 58 w/m. K; The coefficient of thermal conductivity of ash sand brick is 0. 528W/m·K), about 1/6 of ordinary concrete. Practice has proved that the heat preservation effect of 20 cm thick aerated concrete wall is equivalent to the heat preservation effect of 49 cm thick clay brick wall, and the heat insulation performance is also greatly superior to 24 cm brick wall. In this way, the thickness of the wall is greatly reduced, and the effective use area of the building is expanded accordingly, the thickness of the building materials is saved, the construction efficiency is improved, the project cost is reduced, and the weight of the building is reduced.


3. High strength


The test results show that the compressive strength of aerated concrete block is greater than 25 kg/cm2, which is equivalent to the compressive strength of no. 125 clay brick and lime sand brick.


4. The earthquake-resistance


In magnitude 7.8 tangshan fengnan and other places of the earthquake, according to the earthquake investigation, aerated concrete building only a few new cracks, and brick structure building almost all collapsed, so that the two not far from each other, the same structure and different materials of the building formed a bright contrast. This is because the aerated concrete has light bulk density, good overall performance and small inertia force during the earthquake, so it has a certain seismic capacity. This will be of great benefit to our earthquake-prone country.


5. Good working


Aerated concrete has good processing performance. Can saw, can plane, can nail, can mill, can drill. And can add reinforcing steel in the manufacturing process. It brings great convenience and flexibility to the construction.


6. High temperature resistant


When the temperature of aerated concrete is below 600℃, its compressive strength increases slightly. When the temperature is about 600℃, its compressive strength is close to the compressive strength at room temperature, so the fire performance of aerated concrete as a building material reaches the national grade ONE fire protection standard.


7. Sound insulation sex


From the aerated concrete pore structure, because the internal structure of aerated concrete is like bread, there are a large number of closed pores evenly distributed, so it has the sound-absorbing performance that general building materials do not have.


8.Mechanization 


Prefabricated aerated concrete assembling large slab can save finished product stacking space; Save masonry labor; Reduced construction work; The construction progress is accelerated and the construction efficiency is improved.


9.Adaptability


Can be tailored according to local different raw materials, different conditions. Raw materials can choose river sand, fly ash, ore and other kinds, according to local conditions. And can waste utilization, environmental protection, the real waste into treasure. The strength value of the aerated concrete block produced by the aerated concrete equipment is relative to a certain water content state, which is called the base water content. However, the range of the base water content of the strength varies from country to country, for example: The standard of Germany, THE European Union and the United Kingdom requires the basic moisture content to be (6±2)%. The starting point is that the water content of the products on the wall is finally 2%-8%. In Sweden and other countries, the air-dry state of the aerated concrete block is the benchmark, that is, the moisture content is (10±2)%; However, in China, the grade of compressive strength is evaluated according to GB/ T1169-2008 "Test Method for Autoclaved Aeration Performance", "Moisture content of 8~12% is required for compressive test". (GB/T11971-1997 "Test Method for Performance of Aerated Concrete" stipulates that the compressive strength of products should be carried out under the mass moisture content of 25%-45%. The moisture content in the stable stage of test strength, i.e. 25%-45%, is very different from the actual water content in the wall, so it will affect the quality assessment of the compressive strength of aerated concrete, and has been abolished).

 

Three, construction method


1. Aerated concrete block masonry is generally used for filling walls. The strength grade of the block used is generally A3.5 for partition walls and A5 for external walls. Mortar strength not less than M5.


2. Before construction of aerated concrete blocks, block arrangement drawings shall be drawn according to the plane and elevation drawings of the building. The number of skin blocks and block height are drawn on the number of skin blocks and the alignment line is drawn between the upper edge lines of the relative blocks, and the masonry is built according to the alignment line.


The masonry surface of aerated concrete blocks should be properly watered. Special tools (paving shovel, saw, drill, carving, flat frame, etc.) should be used for laying aerated concrete.


3. The vertical grey joints of the upper and lower leather blocks of the aerated concrete block wall should be staggered with a staggered length of 300mm and not less than 150mm. If not, set 2 φ 6 reinforcement or φ 4 steel mesh in the horizontal ash joint, and the length of the reinforcement or steel mesh should not be less than 700mm.


4. The gray joints of the aerated concrete block wall should be horizontal and vertical, and the mortar should be full, and the plumpness of the horizontal gray joint mortar should not be less than 90%; Vertical mortar plumpness should not be less than 80%. The thickness of horizontal grey seam and the width of vertical grey seam should not exceed 15mm.


At the corner of the aerated concrete block wall, the vertical and horizontal wall blocks shall be laid against each other, and the skin block shall be exposed. At the t-junction of the aerated concrete block wall, the transverse wall block shall be exposed from the skin and sit in the longitudinal wall block.


5. Aerated concrete block walls shall not be used in the following areas without effective measures:


(1) the part below the moistureproof layer of the building;


② Long-term immersion or chemical erosion environment;


(3) the wall with vibration source environment for a long time;


(4) The surface of the block is often in a high temperature environment above 80℃. Scaffold holes shall not be provided on aerated concrete block walls. The block walls of each floor shall be completed consecutively and not be connected. If you must leave a croucher should be left into a croucher, or in the side of the door and window hole.

 

Four, raw material coordination


Aerated concrete blocks, like other concrete, are made of several materials. Therefore, there is the question of which materials to use and how much of each material to use. The percentage of the amount of each ingredient used in an ingredient is called the mix.


For aerated concrete, to determine a good mix ratio, the following requirements must be met:


(1) Products have good performance, in line with the requirements of the building. In many properties, the first is the volume density and compressive strength, at the same time, but also to consider the durability of products and other properties.


(2) The product or body has good process performance and is suitable for factory production conditions. Such as pouring stability. Slurry fluidity (consistency), hardening time and simple process flow, etc.


(3) The raw materials used are of less variety, wide range of sources, low cost, no pollution or low pollution, and as much as possible use of industrial waste. The determination and use of aerated concrete mix ratio, generally through the theoretical mix ratio of research and test, production with the determination of the basic mix ratio, and consider the mix ratio of the economy, the final calculation to determine the formula.


Friends, that's all for this little lesson! If you have any questions, please pay attention to the wechat public number "Beautiful Villa" to leave a message in the background, or call 400-090-6070 consultation hotline!

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