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Compared with the composite external wall insulation and energy saving system, the autoclaved aerated concrete block wall has the following advantages: the base wall and the insulation layer are combined into one, and they will not deform or fall off under the wind load; the fire performance meets the requirements of the specifications ; Durability meets full requirements; strong machinability; construction process is relatively simple; adjust indoor environment, etc. One of its main disadvantages is that it is prone to cracks. This article introduces some specific measures to prevent cracks in autoclaved aerated concrete block walls.

1. Add construction column

The integrity of the block wall is poor, and it is easy to cause cracks in the wall. One of the measures to improve the integrity of the block wall is to add structural columns at the middle of the elongated wall, at the corners of the wall and at the junction. The structural columns in the enclosure wall or partition wall of autoclaved aerated concrete blocks are not completed into large teeth. The tie bars between the masonry wall and the structural columns are preferably 3.5mm mesh and 20mm welded steel bars Net, hot-dip galvanized steel sheet with thickness of 2mm can also be used. The end that protrudes into the structural column is made into a dovetail shape, which is conducive to the compaction of the concrete. The steel plate built into one end of the masonry should be drilled with two holes and nailed into the block with cement steel nails. Reinforced mesh or steel plate knots should be installed along the wall every 500mm or between two leather blocks. In addition, reinforced concrete horizontal tie beams can also be added.

2. Reserved seam treatment

In the routine practice of masonry engineering, when filling the wall until it is close to the beam and the bottom of the slab, a certain gap should be left. After the filling wall is completed and at least 7 days apart, it will be squeezed and squeezed. . With this method, cracks may occur on the bottom of autoclaved aerated concrete masonry walls and reinforced concrete beams (slabs). It is best to reserve gaps in the autoclaved aerated concrete block-filled wall, which can be controlled at 10mm ~ 25mm, the gaps can generally be filled with expanded cement mortar (with UEA expansion agent added with 12% cement weight), and the gaps can be copied over 25mm. Expanded fine concrete embedded filling. When embedding an external wall, you can embed it on the inside first, and after the final setting of the expanded cement mortar or expansive fine stone concrete is finalized, then embed the outer side, so that it can be solid. Expanded cement mortar or expanded fine stone concrete after embedding should be moisturized and cured. Flexible materials can also be used for embedding, such as glass fiber wool, mineral wool and PU foaming agent (strip), and then elastic glass tape is applied on the surface for protection.

3. Knotted steel bars or L-shaped iron parts

The cracks at the junction of the block wall and the reinforced concrete frame column or shear wall can be controlled by the use of tie bars or L-shaped iron parts. It is best to use 3.5mm mesh and 20mm welded steel mesh for the tie bars. When L-shaped iron parts are used, the thickness should be kept to 2mm, and a gap of 10mm to 15mm should be reserved between the block wall and the reinforced concrete frame column or shear wall. After the wall is completed, the gap is embedded with flexible materials fill.

4. Strengthen the treatment of doors and windows

When the width of the door opening is greater than 2m, reinforced concrete frames should be set on both sides of the opening to avoid the vibration of the block wall at the contact portion with the door frame caused by the opening vibration of the door leaf. Reinforced concrete window sill beams should be used for the windows, with both ends extending into the wall 600mm each. The bottom of the skin block under the window should be placed with 3Ф6.5mm longitudinal reinforcement, which is suitable for welding! Welded reinforcement mesh with 3.5mm mesh size of 20mm, the length of the two ends extending into the wall should be ≥700mm.

5. Temperature influence

Reduce the outer surface of the roof and wall concrete components. Because the linear expansion coefficient of reinforced concrete is greater than the linear expansion coefficient of autoclaved aerated concrete blocks, under the action of thermal expansion and contraction, the expansion and contraction between the reinforced concrete components and the block wall Not synchronized, will cause cracks in block walls or reinforced concrete beams and columns. In view of this situation, the exposed reinforced concrete columns and beams can be designed as special-shaped structures to minimize the effect of temperature changes on concrete members.

6. Grey seam control

To improve the thermal insulation performance of the wall, it is not necessary to reduce the dry density of the light-weight blocks, but also to avoid the thermal bridge caused by large ash joints and uneven ash joints. The thermal conductivity of ordinary masonry mortar is about 3 times that of lightweight blocks. If the thickness of the ash joint can be reduced to about 3mm, the thermal bridge generated by the ash joint can be ignored. To reduce the thickness of the ash joint, the masonry must use a conversion binder that matches the material properties of the autoclaved aerated concrete, and its main technical indicators should be in accordance with JC 890-2001 In addition to the requirements for masonry mortar in the “Plastering Mortar”, it should also meet the relevant requirements.

7. The cracking of the plaster layer

(1) At the junction of block masonry and reinforced concrete columns (beams, walls), alkali-resistant glass fiber mesh cloth or hot-dip galvanized steel wire mesh ≥500mm wide should be laid.

(2) The decorative construction of block masonry should be carried out at least 7 days after the completion of the filling of the voids in the top of the masonry wall.

(3) Doors, windows, and side walls of various types of boxes should be filled and stricken layer by layer to avoid hollows and cracks at the junction of the side walls of the frame and the masonry. Around the frame where sealant is required, a gap of 7mm deep and 5mm wide should be left when plastering, so that caulking can be applied. The gap between the window board, watch box, fire hydrant box, telephone box and the masonry should be filled with PU foaming agent.

(4) Before plastering the block walls, the interface agent needs to be painted. If there is no special-purpose interface agent, it can be prepared with 999 strong-strength glue: cement: fine sand = 1: 2: 2 (mass ratio).

(5) Special-purpose plastering mortar shall be used for plastering of block walls, and its technical index shall meet the requirements of plastering mortar in JC 890-2001 “Masonry Mortar and Plastering Mortar for Autoclaved Aerated Concrete”.

(6) If there is no special method for plastering the external walls of the block-use plastering mortar, polymer cement mortar should be used for the first plastering, the thickness is 6mm, the mixing ratio of polymer cement mortar is 1: 4, cement mortar is mixed with water The amount of 801 glue is 20%.

(7) If there is no special-purpose plaster for internal wall plastering, polymer cement mixed mortar should be used. Its mixing ratio is cement: lime: yellow sand = 1: 1: 6, and the water consumption of mixed mortar mixed with mortar is 20% Of 801 glue. After drying, the second polymer cement mixed mortar plastering and calendering; can also be used trowel ash, paper bar ash or alkali-resistant short-fiber mortar plaster. In order to imitate and reduce cracking, elastic putty and elastic paint are used for both the inner and outer walls.

The above are some effective measures to control the cracks in the autoclaved aerated concrete block wall, but taking these measures can not completely eliminate the cracks in the masonry, and we need to further accumulate experience in the future application process, Continuous improvement.

A sudden epidemic COVID-19 caused China and even the world economy to shut down.With the exception of epidemic prevention materials, all markets are depressed. Therefore, many practitioners in the building materials industry have fallen into anxiety. But in my opinion, this anxiety is actually unnecessary. The building materials industry is mixed, and some building materials companies are backward and inefficient, and their original duties have not been done well. Even if there is no epidemic, they will be eliminated in 3-5 years. The epidemic only accelerates the speed of elimination. However, the suspension of various industries has given all companies a chance to correct their mistakes. Building materials are just needed in any country and any dynasty. If you do your own thing well, why are you anxious? Therefore, for companies with strong immunity, the current difficulties must be temporary.

Fortunately, under the increasingly fierce competition, many companies began to reflect on and make up for lessons, seeing the nature of the industry through external factors: the reason why the market truly accepts new building materials is nothing more than quality and convenience. Everything returns to the same origin, the same principle of all building materials: products and services. The logic of industry evolution has always been “continuous innovation around customer value.” No company is isolated. If the environment has changed, but the company itself has not changed, then it violates the evolutionary law of survival of the fittest and natural selection and it will also face the risk of being eliminated. Therefore, in the face of environmental changes under the epidemic, the building materials industry must also take the initiative to change. These changes are mainly reflected in the following aspects:

Changes in the market brought by the epidemic: During the home stay, people can better understand the importance of Home & Decoration. After the epidemic, it will stimulate the secondary decoration market or increase the new house decoration budget, and promote the “home economy”. The increasing of home functions, the improvement of health requirements, and the improvement of storage space, rapid, healthy, green, and environmental protection will further become the mainstream consumer trend of home building materials and home improvement. In addition, personalized products will also receive more attention, personalized products that were not easy to promote will be better promoted.

Changes in marketing brought by the epidemic: the products that are sold must be “seen” by customers, which is still the goal of marketing. Online sales rely on content to gain customers, more precisely, value. The service concept will become an important means of linking enterprises and customers, and product details and effects will be more in line with personalization. After the popularization of 5G, online activities will become more and more open. Various forms such as graphics, short videos, and audio will emerge in an endless stream. The community construction of enterprises will become the core marketing position. Market research, new product research and development, product promotion, zero-touch transaction, smart logistics, and remote services will quickly promote the integration of online and offline, so as to realize the marketing concept based on customers’ deep-level needs. For offline stores, their functions will become more and more consumer experience rather than simply selling products.

R & D changes brought by the epidemic: R & D of products will not be limited to the products themselves, more attention will be paid to the convenience of application, and every effort will be made to minimize the amount of after-sales service. This requires companies to sell not semi-finished products, but “products + Service “complete system, including products and related tools, guidance, and can even help customers to “DIY”.

Management changes brought by the epidemic: The epidemic has actually practiced online office. According to statistics, on February 3, 2020, more than 200 million people of China worked online from home. For many companies, this is a new model, and the corresponding management mechanism needs to be improved, so as to achieve the goal of “Physically dispersed but mentally concentrated”. We call it “bulk management” for now. Because of the habit, the efficiency of online office will indeed be relatively poor, and not all types of work are suitable for online office, but the future is likely to be a state of online and offline parallel. This is very beneficial to small, medium and micro enterprises. Enterprises can save office, administrative and logistics costs, and employees can save transportation costs and commuting time. Except for cement, glass, ceramics, most of the building materials companies are small, medium and micro enterprises, they have a larger spread of these costs. Under the severe economic situation, as long as the management mechanism is improved, online office is very likely.

Production changes driven by the epidemic: The implementation of intelligent manufacturing, unmanned industrial production, and the intelligentization of upstream and downstream supply and marketing will accelerate the pace. The reduction of human factors will promote the development of the sharing economy more quickly. Brands, technologies, production, sales, finance, and logistics resources will be fully integrated. The idea of investment or factory construction will be completely changed, the upstream and downstream markets will be further integrated, and part-time sales of delivery drivers are increasingly common.

Positioning changes brought by the epidemic: After the environment changes, the structure of enterprises will change at the genetic level, leading to evolution. According to the model of “assembled enterprise”, it needs a clearer positioning from industry, enterprise to individual. First, employees should position their value, and then strengthen their capabilities in this field, so as to stabilize their position in one or more organizations and reap the corresponding rewards. This remuneration is similar to dividends, that is, employee bossing. “Assembly enterprise” assembly elements, without investment and construction of factories, without pre-employment training and daily expenses, is the most competitive organizational operation mode, and it has been implemented in the construction industry. After the employee bossing, the position of the boss will become the initiator and organizer. With insights into market demand and resources, the boss adjusts his position in the industry chain, establishes a brand-new product echelon, then organizes relevant elements, formulates cooperation mechanisms, establishes a digital and information management platform, and faces the market together.

The above changes are certainly not the full impact of the epidemic. All in all, all changes begin with a change in thinking. No change in thinking, everything will be impossible to talk about.

APEX new plant to be put into production soon with advanced EU technology.

There are many construction supplies made of autoclaved aerated concrete, the common one is the cement brick, which is the basis of our building. Autoclaved aerated concrete blocks are such a process. So what is autoclaved aerated concrete blocks? What are the processes of autoclaved aerated concrete blocks? In order to let more friends have a comprehensive understanding of this, autoclaved aerated concrete block manufacturers bring you A comprehensive introduction.

What is autoclaved aerated concrete block

Autoclaved aerated concrete blocks are made of calcium materials (such as cement, lime) and siliceous materials (such as sand, fly ash, slag) by adding aluminum powder to make an aeration agent, which is stirred and cast by water. , Porous expansion and pre-curing cutting, and then porous silicate block made by high-pressure steam curing. The weight per unit volume of autoclaved aerated concrete blocks is one-third of clay bricks, thermal insulation performance is 3-4 times that of clay bricks, sound insulation performance is 2 times that of clay bricks, and impermeability is more than double that of clay bricks. , Fire resistance is 6-8 times that of reinforced concrete. The masonry strength of the block is about 80% of the strength of the block itself (30% for red bricks). The construction characteristics of autoclaved aerated concrete blocks are also excellent. It can not only produce various specifications in the factory, but also can be sawed, planed, drilled and nailed like wood. Due to its large size, the construction speed It is also fast and can be used as a filling material for various buildings.

Autoclaved Aerated Concrete Usage

AAC is a highly thermally insulating concrete-based material used for both interior and exterior construction. Besides AAC’s insulating capability, one of its advantages is quick and easy installation, because the material can be routed, sanded, or cut to size on site using standard power tools with carbon steel cutters.

The process of autoclaved aerated concrete block

1. Raw material storage and supply of aerated concrete blocks

Raw materials are transported into the factory by car, and fly ash (or sand, stone powder) is concentrated in the raw material yard, and it is loaded into the hopper when used. Bagged cement or bulk cement is stored in the cement warehouse. When used, it is shipped into the hopper. Chemicals, aluminum powder, etc. are placed in chemical warehouses and aluminum powder warehouses, respectively, and shipped to production workshops when used.

2. Raw material processing of aerated concrete blocks

Fly ash (or sand, stone powder) is sent to the ball mill through the electromagnetic vibrating feeder and belt conveyor, and the ground fly ash (or sand, stone powder) is sent to the slurry tank for storage by the fly ash pump. The lime is sent to the jaw crusher through the electromagnetic vibrating feeder and the belt conveyor for crushing. The crushed lime is sent to the lime storage bin through the bucket elevator, and then sent to the ball mill through the screw conveyor. The screw conveyor and bucket elevator are fed into the powder batching bin. After a certain proportion of chemicals are manually measured, a solution with a certain concentration is made and sent to a storage tank for storage. The aluminum powder is transported from the aluminum powder warehouse to the production workshop, lifted to the second floor of the batching building with an electric hoist, poured into a mixer to add water quantitatively, and stirred into an aluminum powder suspension.

3. Ingredients, mixing and pouring of aerated blocks

Lime and cement are successively sent to the automatic weighing scale for accumulative measurement by the screw conveyor under the powder batching bin. There is a screw conveyor under the scale to evenly add the materials to the pouring mixer. Fly ash (or sand, stone powder) and waste slurry are put into the measuring cylinder for measurement. When the mold is in place after the measurement of various materials, the slurry can be stirred. The slurry should meet the process requirements before pouring (about 45 ℃), if the temperature is not enough, steam heating can be done in the slurry metering tank, and the aluminum powder suspension is added 0.5 to 1 minute before the material is poured.

4. Priming and cutting of aerated blocks

After pouring, the mold is pushed into the initial raising room with a conveyor chain for initial gas evolution. The room temperature is 50 ~ 70 ° C, and the initial raising time is 1.5-2 hours (this process can be eliminated according to the geographically favorable strip cutting machine). Then use a negative pressure spreader to hang the mold frame and the blank together on the cutting table where the bottom plate of the kettle is placed in advance, remove the mold frame, and the cutting machine performs cross-cutting, longitudinal cutting, milling the bread head, and the mold frame is hung. Go back to the mold truck to manually clean and degrease, and then hang on the mold truck to form the mold for the next pouring. The cut green body and the bottom plate of the kettle are hoisted to the top of the kettle with two cranes. There are four layers between the layers. Each brace is composed of several tank cars. The blanks and corner wastes generated during cutting are sent to the waste slurry agitator beside the cutting machine through a screw conveyor, and water is added to make waste slurry, which is used for batching.

5. Autoclaved aerated block and finished product

After the marshalling is completed on the parking line in front of the kettle, the autoclave kettle door to be exited is opened, the finished kettle in the kettle is pulled out with a hoist, and then the kettle for the autoclave is pulled into the autoclave with a hoist Kettle for maintenance. The finished product on the tank car is hoisted to the finished product warehouse with a bridge crane, and then transported to the finished product yard with a fork-lift truck. The empty tank car and the bottom plate of the kettle are hoisted back to the carriage return line. For the next cycle.

Prefabricated buildings began to attract interest in the early 20th century and were finally realized in the 1960s. Britain, France, the Soviet union and other countries first tried. Because prefabricated buildings were built quickly and cost less to produce, they quickly spread around the world. The early prefabricated buildings were rigid in appearance. Later improvements were made to the design, adding flexibility and variety, so that prefabricated buildings could not only be built in batches, but also in a variety of styles.

1. Block building

A large number of building components, such as exterior wall panels, interior wall panels, laminated panels, balconies, air conditioning panels, staircases, prefabricated beams, prefabricated columns, etc. are all produced and processed by the workshop.

2. Panel building

It is assembled from prefabricated large inner and outer panels, floor panels and roof panels, and is also known as the big board building. It can effectively reduce the structural weight, improve labor productivity, expand the use of the building area and seismic function, is the main type of prefab building.

Wallboard is divided into load-bearing type wallboard and decorative wallboard, load-bearing wallboard is mostly reinforced concrete board, decorative wallboard such as exterior wallboard is mostly reinforced concrete composite board with insulation layer, and special steel and wood insulation composite board with exterior veneer wallboard. All kinds of plate hoisting group can bear the load, the construction speed is fast, the construction price is low!

3. Box architecture

It is a kind of prefabricated building developed from the plank building. The biggest characteristic is to make all room unit or cubicle kitchen, toilet or stair well into load-bearing box in construction, wait with wall board and floor board to form integral whole again. This kind of building factory is changed the degree is higher, the spot installs faster, not only can complete the structural part of the box in the factory, and the interior decoration and the equipment also can do well, even furniture, carpet and so on also can complete completely, the spot hoisting, connect good pipeline can use!

4. Skeleton plate construction

It consists of prefabricated bones and plates. Its load-bearing structure generally has two forms, one is composed of columns, beams load-bearing frame, and then use the floor and non-load-bearing internal and external wallboard frame structure system; The other is a load-bearing plate and column structure system composed of columns and floor slabs. The load-bearing frame can be a heavy reinforced concrete structure or heavy steel structure, with light weight and flexible internal separation, suitable for multi-storey and high-rise buildings.

 

With the development of modern construction industry, the term “prefabricated building” is frequently mentioned from top to bottom. Prefabricated building, “building like building blocks”, has become a new trend in the international construction industry. This is not new. It started in Germany in the middle of the 19th century and was invented with the innovation of building materials. As early as the 1950s, during the first five-year plan period, China began the exploration of prefabricated buildings.

With the increase of labor cost, the improvement of environmental protection requirements, and the improvement of occupational health and operating environment of the labor force, it is an inevitable trend for the construction industry to develop toward the direction of building industrialization, and the prefab construction mode is bound to become the mainstream of the development of the construction industry.

The prefab way of production is different from the traditional way of construction, which often gives people the impression that the construction site is noisy, dusty and full of garbage. But compared with traditional buildings, prefabricated buildings behave very differently. “In addition to reducing environmental pollution during construction, it also significantly reduced the amount of dust and construction waste by 70 percent.

Compared with the traditional construction method, it can save water by 25%, reduce the amount of plastering mortar by about 55%, save the template by about 60%, reduce the energy consumption by 20%, greatly reduce the energy consumption in the construction process, improve the project quality and labor production efficiency, and shorten the comprehensive construction period by 25%-30%.

With the gradual improvement of prefabricated building technology research, the rise of labor cost and the increasing voice of green building, China is ushering in a new stage of prefabricated building development.