Study on the reuse method of construction waste?

It is very important to study the reuse method of construction waste. Only by rational utilization of construction waste can we reduce environmental pollution and even generate economic value. Zhong Da Consulting Company will introduce you to the research on the recycling method of construction waste.

1. Introduction

With the rapid development of the city, a large number of old buildings have been demolished and rebuilt in batches, and new buildings have sprung up. In this process, a large number of abandoned concrete, masonry, damaged building components and other building materials have been produced. These artificial materials can be found everywhere in the cities under construction. They are huge in number and complex in composition, and it is difficult to integrate with the natural environment. According to relevant data, the total amount of urban building demolition garbage in China is about 21-280 million t, and if it is disposed by stacking, it will occupy land1.50-0.2 billion m2. Therefore, how to deal with them is a problem that every city has to face. Making full use of such a huge amount of concrete, masonry, metal and other wastes generated by the demolition of old buildings can not only reduce the damage to the environment, but also effectively reduce the waste of building resources. As early as 1946, Russia first studied the reuse of concrete produced in the process of building demolition, which opened a precedent for the study of urban construction waste treatment methods. Subsequently, the Netherlands, Denmark, the United States, Germany and other countries also joined the research ranks of construction waste reuse and carried out various practices. Among them, Germany is the first country to legislate on the reuse of construction waste. Relevant data show that in China, the recovery rate of construction waste is less than 5%, far below the international level. In the process of rapid urban construction, a large amount of construction waste is usually only landfilled, which fails to make full use of construction waste and wastes resources to some extent. Therefore, only by learning from the valuable experience of the above countries and combining with China's actual national conditions can we effectively carry out the research on the recycling of construction waste in China and more effectively improve the efficiency and level of recycling of construction waste in China.

2. Composition and characteristics of construction waste

2. 1 Composition of construction waste

Construction waste refers to the abandoned environmental materials and artificial building materials produced in the process of building demolition and construction. They can be earth and stone removed during the construction of bases and roads, or waste cement, building templates and plastic insulation boards produced during the construction. It can also be concrete chips, blocks, wood and metal single materials or composite building components such as doors, windows, floors, etc. formed after building demolition. According to the different composition of materials in construction waste, construction waste can be divided into 10 categories, such as soil waste, concrete waste, asphalt waste, wood waste, metal waste, plastic waste, paper waste, organic waste, hazardous waste and mineral waste.

2.2 Characteristics of construction waste

The most remarkable feature of construction waste is its large output. Relevant data show that in 2005, the output of urban construction waste in China was about 400 million tons, that in the United States was 65.438+0.3 billion tons, that in Austria was 46.5438+0 million tons, and that in Germany was 245 million tons (in 2004). A huge amount of urban construction waste accounts for more than 40% of the total urban waste, and more than 80% of urban construction waste comes from the demolition of old buildings. With the aging and renewal of urban buildings, the output of construction waste will continue to increase under certain conditions. A large amount of construction waste has brought many problems and opportunities to the city. Urban construction waste has potential resource development value. Because of the huge amount and universality of construction waste, a large part of construction waste has the value of recycling. For example, concrete, which accounts for a large proportion of construction waste, can be reused only after simple treatment because of its huge quantity and stable material. By using crushed concrete materials with good compression resistance and stability, the concrete materials with larger particles can be made into foundation fillers for buildings or road engineering after simple screening and crushing; After fine grinding, large concrete can form fine sand-sized particles, which can be made into building blocks, or further divided into sand, gravel, cement and other materials for building, reducing the use of unnecessary new materials.

3. The hazards of construction waste

Before being recycled, urban construction waste is usually piled up or landfilled. Either way will have a negative impact on the city and the environment.

3. 1 Destroy urban environmental landscape and occupy land.

In China, a large amount of construction waste, such as bricks, stones, concrete slag, building floors, doors and windows, etc., generated during the demolition of old buildings is usually disposed of in the form of stacking. However, due to the negligence of management, many construction sites randomly dump the demolished construction waste in rural areas around the city or on both sides of roads. Due to the existence of construction waste, the landscape environment in these areas has been seriously damaged. In many cities, even if construction waste is buried and piled up in a planned way, it will have a negative impact on the environmental landscape. Urban construction waste landfills need to occupy a lot of land, and a large area of construction waste materials is extremely out of harmony with the surrounding natural environment.

3.2 Environmental pollution

Urban construction waste will produce a lot of dust in all aspects of production, transportation and treatment, which will float in the air and affect the air quality of the city. If construction waste is simply piled up, it will also cause more hidden damage to the natural environment. Because there are a large number of substances in construction waste that are prone to physical and chemical changes, such as paints, coatings, cement, metals, etc., after weathering and rainwater wetting, these may form tiny particles and float into the air, or form acidic substances that flow into rivers or penetrate into the ground with rainwater, polluting water bodies and causing damage to the environment.

4. Resource utilization method of construction waste

4. 1 policy guidance

Reuse of construction waste is one of the important ways to reduce the waste of construction resources and protect the environment. China's research on the recycling of urban construction waste started late, but in recent years, drawing on the practical experience and research results of other countries, China has formed a relatively perfect management system for recycling construction waste.

4.2 Reuse of original components and materials of old buildings

In practice, flexible recycling methods can be adopted according to the different properties and components of construction waste. When the original components or materials of the old building can be completely removed from the old building and remain, and still have a certain strength, if these materials bear the imprint of a specific historical period and a specific environment, they are very suitable for use in new buildings. In the process of renovation, the School of Architecture of Inner Mongolia University of Technology adopted the beams, columns and other building components and equipment that can be used continuously from the old buildings as the indoor landscape of the "new building", which not only showed the architectural characteristics, but also reduced a lot of construction costs by using construction waste. There are many kinds of construction waste, and the quantity is considerable. Using construction waste to enrich urban topography and landscape, urban mountain parks can be formed through greening and transformation; You can make city sketches with discarded building materials. These building materials are unique in the construction of urban landscape environment by virtue of their unique rough and broken texture. Making good use of urban construction waste can play an active role in beautifying urban environment and creating urban landscape environment.

4.3 Re-processing and Utilization of Old Building Materials

Recycling abandoned construction waste is the most effective way to consume a lot of construction waste. In China, the production of recycled bricks is one of the important methods of recycling construction waste, and it is also the most important part of industrial utilization of construction waste in China. The production of recycled bricks is to crush, film-press and steam concrete and other materials in construction waste. In Europe, the recycling of construction waste is very extensive. Materials such as concrete, cement, wood and glass in construction waste can be used after simple reprocessing. Figure 1 Walkways (left) and salons (right) inside the building (photo source: taken by the author)

5. Application case of construction waste reuse

5. 1 School of Architecture, Inner Mongolia University of Technology

The teaching building of the School of Architecture of Inner Mongolia University of Technology was rebuilt from the foundry workshop of an abandoned machinery factory in the campus. The reformed teaching building not only retains the rugged beauty of the original industrial building structure and materials, but also makes use of the spatial characteristics of the factory building to decorate rich teaching space, office space and public space. At the same time, in the interior decoration and exterior landscape design of the building, the abandoned mechanical equipment, abandoned doors and windows and abandoned bricks in the original building are fully utilized to form practical and decorative architectural sketches and furniture. As shown in figure 1. The seats in the public corridor inside the building are composed of abandoned mechanical equipment and simple wooden seating surfaces. The bar, shelves and seats of the salon in the department hall are also welded into frames with abandoned metal square pipes and round pipes in the original factory building, plus simple wooden boards. The external landscape of the building is more distinctive. As shown in figure 2. The landscape at the entrance of the building is arranged by reinforced concrete beams removed from the original building. The steel bars and metal embedded parts on the beams are clearly visible, with dark red rust left by the years. The decorative lines on the facade of the building and the decoration on the wall between windows are welded by corroded waste iron sheets and angle steel. The landscape wall of the surrounding environment of the building is also spliced by the waste angle steel removed from the old building. The interior and exterior decoration of this building uses a lot of waste building materials and equipment, which not only greatly reduces the construction cost and saves resources, but also forms a distinctive architectural image.

5.2 Super Adobe Building Sketch

"superadobe" was created by Iranian architect Nader? Khalili's new building system. This system mainly uses natural materials such as soil and sand to form a dome-shaped building through rapid accumulation. Its purpose is to provide fast, simple and cheap housing for the poor after the disaster. Superadobe architectural sketch is located in Wuhai Youth Creative Industrial Park, Inner Mongolia, which combines khalili's design concept with local abandoned building materials to form an architectural sketch integrating function and landscape. As shown in figure 3. In this sketch, the remaining sand and gravel materials after the construction of the industrial park are put into woven bags and the initial shape of the building is formed by bricklaying. After wetting, settling, beating and molding, cement and yellow sand are coated on the outside of the building for reinforcement. The whole sketch is based on Mongolian yurts, and consists of units, groups and components. The spatial combination of sketches is flexible and free, which can not only meet the functional requirements, but also perfectly combine with the local environment.

6. Conclusion

With the increasingly prominent global environmental pollution problem, how to solve the problem of urban construction waste pollution has become more and more serious. China is in a rapid period of urban construction and development. The amount of urban construction waste generated in the process of urban demolition and construction is huge, the problem is more prominent, and the demand for resource treatment of construction waste is more urgent. Based on the classification study of construction waste, some hazards and reuse methods of construction waste are analyzed. However, only a small part of construction waste can be identified, and more content will be studied in the future. The formulation of construction waste control policies, the development of construction waste recycling methods and the methods to reduce the output of construction waste will be explored in depth with the progress of the times and the development of science and technology.

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