Reasonable selection and configuration of the hott

2022-07-27
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Reasonable selection and configuration of asphalt pavement maintenance machinery

asphalt road is the main operating road in China today, and more than 50% of the road traffic is completed through asphalt road. Asphalt road maintenance works have a large amount and a wide range. With the different geographical and climatic conditions, the connotation of maintenance works is also different. Therefore, there is a large demand for road construction and maintenance machinery suitable for the maintenance of asphalt roads, with many varieties, specifications and series. It is also one of the machinery and equipment owned by road maintenance engineering units at all levels. These equipment mainly include asphalt melting and heating equipment, asphalt emulsifying equipment, asphalt mixture mixing equipment and paver, asphalt distributor, liquid asphalt transport vehicle, asphalt pavement milling machine, asphalt mixture plant mixing and recycling equipment and asphalt pavement local recycling equipment. In the face of so many equipment, how to reasonably configure and select the type is an important content of the maintenance department

1 reasonable configuration and selection 1 The three principles that the experimental equipment (resonant reactor, voltage divider, excitation transformer, etc.) should be as close to the tested cable head as possible

the maintenance of the road surface is a systematic project. In the process of configuring the maintenance machinery, a systematic idea should be established and the system principle should be observed. That is to say, the maintenance machinery configuration scheme must be formulated from the overall situation of the whole pavement maintenance operation, based on the overall goal of the maintenance operation system. In addition, we should also pay attention to the following three principles:

(1) engineering applicability

in the process of model selection, machinery should be reasonably selected according to the conditions of the pavement to be maintained and the working environment. For example, the maintenance of asphalt pavement is discussed here, so the selected equipment must mainly serve the asphalt pavement. In addition, our country has a vast territory, and the geographical and climatic conditions change greatly. We should also make full consideration in the selection of models. It can be said that it not only improves the quality of commodities

(2) progressiveness in technology

a device with advanced performance and technology has a production capacity several times that of a relatively backward model. Advanced equipment is selected, which has high production efficiency, low failure rate, less time for manual maintenance, and generally guaranteed operation quality

(3) economic rationality

in the process of selecting machinery, priority should be given to the allocation of some equipment that has a significant impact on the maintenance work according to the economic bearing capacity of the unit, and then the equipment should be continuously updated and improved according to the capital status of the unit, so as to gradually improve the equipment level. At the same time, the technical level of the operating personnel of the unit shall be considered to avoid that the equipment purchased at a high price can not be manipulated, resulting in a waste of resources and increasing the cost of the maintenance project

2 seven elements of machinery selection

according to the above principles, the following seven elements should also be considered in the specific machinery selection:

(1) working capacity

try to select a machine that can be used for multiple purposes. Its power equipment is mainly small and medium-sized diesel engines, and appropriately equipped with large power equipment (small: 60 kW). Transportation machinery and equipment: dump trucks are mainly used for transportation with a distance of more than 50 km; Medium and small tonnage trucks or trailers are the main ones with a haul distance of less than 50 km; Short distance transportation is mainly conducted by motor tippers or agricultural transporters. Of course, the selection of truck tonnage should consider the size of traffic volume

(2) reliability

the selected equipment should not only be reliable in performance, but also in operation quality

(3) durability

the machine can be used for a long time, and can work well under bad working conditions, reducing the cost of equipment maintenance

(4) universality and compatibility

the selected equipment shall be compatible with other equipment as far as possible, and the accessories can be used interchangeably. It is better to use it together with the previously configured machinery to effectively avoid the pollution of hydraulic oil caused by external impurities entering the hydraulic system

(5) safety and environmental protection

at present, environmental protection is an important part of China's economic development, so clean and pollution-free or less polluting machinery should be selected as far as possible

(6) maintainability

the equipment is convenient for maintenance and daily maintenance

(7) economic benefits

each equipment should be considered to improve its economy, so that the economic benefits of the entire highway maintenance department will be improved

3 selection of asphalt pavement maintenance machinery

selection of asphalt pavement maintenance and small environmental pollution machinery, in addition to considering the above three principles and seven elements of equipment selection, specific machinery shall be selected according to the content of operation

next, we will analyze the main equipment used in asphalt pavement maintenance and their selection

3.1 selection of pavement milling machine

pavement milling machine is one of the leading machines for cold milling - Hot paving mechanized repair. The production capacity required for the milling process is mainly determined according to the requirements of engineering quantity and construction period. The calculation formula is as follows:

qx=sx/(TKT)

where: QX - the production capacity required for the milling machine, m2/h

sx-- milling area required for milling, m2

t-- scheduled repair days in the construction plan, D

k-- coefficient of commencement day, k= actual working days/planned working days

t-- daily working hours, h/d

for a single milling machine, its production capacity can be determined by the following formula:

qx=bxvxhxkx

where: QX -- production capacity of a single milling machine, m2/h

bx-- milling width, m

vx-- milling speed, m/h

hx-- milling thickness coefficient

kx-- migration coefficient of milling machine

kx=1 - td/t

where: td-- the time of daily migration of milling machine, h

t-- daily operation time, h

number of milling machines required n=qx/qx

3. 2 Determination of the production capacity of asphalt concrete mixing equipment

asphalt concrete mixing equipment is also one of the leading machinery for cold milling and hot paving mechanized construction and repair. Its production capacity shall be calculated according to the milling area and paving layer thickness. The calculation formula is as follows:

qb=qxh ρ Kb

where: QB -- production capacity of mixer, t/h

qx-- production capacity of milling machine, m2/h

h-- thickness of design paving layer, m

ρ-- Density of mixture, t/m3

kb-- matching coefficient. In order to ensure construction continuity, the production capacity of the mixer should be about 1/3 greater than that of the milling machine

3.3 selection of paver

according to the general requirements of maintenance construction, on the premise of ensuring the quality and process requirements of pavement engineering, the production capacity of paver should be 20%~30% greater than the capacity of mixing equipment, and then adjust the paving speed to make the paving speed meet the quantity of materials provided by mixing equipment, and the working capacity of both should be balanced. The production capacity required for the asphalt concrete paving process can be calculated by the following formula:

qt=qbkt1

where: QT -- the production capacity of the paver, t/h

qb-- mixer production capacity, t/h

kt1-- matching coefficient, 1.2~1.4 to ensure the continuity of construction

the production capacity of a single paver is calculated by the following formula:

qt=btvtht ρ Kt2

where: QT -- production capacity of a single paver, t/h

bt-- paving width, m

vt-- paving speed, m/h

ht-- loose paving thickness of paving layer, m

ρ-- Mixture density, t/m3

kt2-- transfer coefficient of paver

kt2=1 - td/t

where: td-- time taken for daily transfer of paver

therefore, the number of pavers n=qt/qt

in addition, there are some options for compaction machinery and transportation vehicles, which will not be repeated here. In short, in the specific construction process, as long as the above principles and elements are fully considered, the equipment can be reasonably configured to improve the work efficiency and economic benefits of their own units

references

1 Xia yuechao et al Highway maintenance and management manual People's Communications Press, hetingji, zhuwentian, dengshixin, etc Manual of road construction machinery People's Communications Press

mailing address: School of engineering machinery, Chang'an University, middle section of the South Second Ring Road, Xi'an (710064) (date of receipt:) (end)

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