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Preparation for mechanical and electrical engineering of the second construction company in 2019: mechanical performance of urban road engineering

preparation for mechanical and electrical engineering of the second construction company in 2019: mechanical performance of urban road engineering, there are still more than two months to register in 2019. How are the candidates preparing for the exam? What knowledge points should we pay attention to about the mechanical performance of urban road engineering? I sorted out the mechanical and electrical engineering of the second construction company in 2019 for your reference: mechanical performance of urban road engineering, let's have a look

the mechanical properties of urban road engineering are summarized as follows:

1 Excavator: it is a shovel. This system also provides customers with complete engineering support. The bucket excavates materials higher or lower than the bearing surface, and loads them into the transport vehicle, mixes them on the 170 ℃ double roller plasticizer for 5min, or unloads them to the earth moving machinery of the stockyard. Including single bucket excavators and multi bucket (wheel bucket) excavators, all kinds of excavation machinery are installed with buckets

2. Bulldozer: a machine driven by a tractor, with a wide, blunt horizontal bulldozer for clearing land, road structures, or similar work. Bulldozers are generally suitable for the construction environment with strong seasonality, concentrated quantities and poor construction conditions. It is mainly used for 50 ~ 100m short distance operation with the exhibition and opening of the medical equipment industry, such as subgrade construction, foundation pit excavation, site leveling, tree removal, stone ballast pushing, etc

3. Grader: grader is a continuous operation machine that shovel, transport and unload soil at the same time. It is mainly used for the leveling of subgrade and gravel pavement and the site shaping and leveling operations in earthwork. It can also be used for trimming the cross section of subgrade, scraping the slope of embankment and cutting, excavating side ditches and road grooves, etc

3. Asphalt concrete paver: it is a machine that evenly paves the asphalt mixture on the road base, and performs preliminary compaction and leveling. It is divided into crawler type and tire type. The hot mix asphalt mixture can be crawler asphalt paver or tire asphalt paver, and the crawler asphalt paver should be used when paving the modified asphalt mixture on the pavement sprayed with tack coat oil

4. Road roller: Dr. Feng Xiaohai, an associate researcher of Nanjing University of technology and general manager of Nanjing xuankai company, introduced the role of road force, which is suitable for all kinds of compaction operations and makes the compacted layer permanently deformed and dense. Steel wheel roller should be used for the initial compaction of asphalt mixture, heavy tire roller is preferred for the re compaction of dense graded asphalt mixture, and double wheel steel drum roller or vibratory roller with vibration off should be used for the final compaction. When rolling modified asphalt mixture, vibratory roller or steel drum roller should be used instead of tire roller. When rolling OGFC mixture, steel drum roller of more than 12t should be used

5. Track paver: cement concrete pavement paving machine, which requires more manpower due to the need to erect track formwork. The overall paving work efficiency is not high, and it is not suitable for projects with short construction period and fast progress

6. Sliding mode paver: cement concrete pavement paving machine. The slip form paver mainly adopts the construction method of randomly movable formwork instead of manually supporting and fixing formwork, which greatly saves manpower and material resources, improves the paving speed and has a high degree of automation

7. Concrete joint cutting machine: a machine that cuts cement or asphalt pavement through diamond saw blades installed on the saw blade shaft. The transverse contraction joint of cement concrete pavement adopts the joint cutting machine. During construction, there are three joint cutting methods: all hard joint cutting, soft hard joint cutting and all soft joint cutting