Why is the road paved with asphalt, and why is asphalt used for paving?

In the highway pavement that has been built in China, more than 90 are semi-rigid base asphalt pavement.

1. Good flatness, stable and comfortable driving, low noise.

2. The asphalt semi-rigid base has the characteristics of high strength, good stability and high stiffness.

3. The cement road belongs to the rigid ground, there must be joints, the construction is more difficult, and the thermal expansion and contraction are also easy to produce cracks.

4. The asphalt construction is fast and the maintenance is also convenient.

Although the cost of asphalt pavement is higher than that of concrete pavement, asphalt pavement has incomparable advantages in terms of long-term benefits and later maintenance and maintenance.

First of all, the wind noise of the asphalt road is small, which is less wear on the tread of the car, and it is also conducive to improving the grip of the car.

The second is the physical characteristics of asphalt pavement, which is mainly manifested in good toughness, good compressive resistance and tensile property, and can better adapt to the not very stable roadbed.

Thirdly, the later maintenance is simple, and partial reconstruction can be carried out, without large-scale construction like concrete pavement, and the maintenance cost is low, which is a problem that has to be considered for infrastructure construction.

Finally, in terms of environmental protection, although the asphalt pavement will cause certain environmental pollution in the process of paving, the asphalt material can be reused as long as it does not react chemically, which effectively improves the utilization rate of resources.

Why do so many people say that asphalt is cheap, asphalt roads are much more expensive than cement roads, and now matrix asphalt ** is about 4000 per ton, and cement is about 300 per ton. The advantages of asphalt pavement are comfortable driving, no noise, and a certain self-healing function, which is generally used for high-grade highways.

First, the construction is fast, the construction period is short, and the open traffic is fast; Second, the degree of construction mechanization is high, and the noise is small; 3. The driving comfort and safety of asphalt pavement are better than those of other pavement; Fourth, the maintenance is convenient, the maintenance time is short, usually the asphalt pavement maintenance cycle is 2 3 days, for the road section with high traffic pressure in the city center can be constructed at night, it can be repaired in a short time, there is no maintenance period and other requirements, and the concrete pavement maintenance takes 30 days or even longer.

Exploit Features:

1: Cheap. 2: Excellent elastoplasticity.

Advantages of paving over cement:

1: Cost in the case of heavy usage.

Special low (asphalt is a by-product of ** refining, while cement is specially produced) 2: day and night or summer and winter temperature difference in the area (northern China) is not easy to crack 3: damage can be repaired in a small area.

Benefits of asphalt pavement:

1.The black road surface is non-reflective and prevents car accidents.

2.Reduced tire wear and reduced noise.

3.Absorbs dust and is environmentally friendly.

4.Facilitate construction and open traffic in a timely manner.

5.Easy maintenance.

The advantages of asphalt are as follows:

**Cheaper than other materials;

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Excellent elastoplasticity ;

The earth DAO area (northern China) with a large temperature difference between day and night or summer and winter is not easy to crack;

Damage can be repaired in a small area;

The black road surface is non-reflective and prevents car accidents.

Reduced tire wear and reduced noise.

Absorbs dust and is environmentally friendly. ；

Facilitate construction and open traffic in a timely manner. ；

Easy maintenance.

Bitumen is a complex black-brown mixture of hydrocarbons of different molecular weights and their non-metallic derivatives, which is a kind of high-viscosity organic liquid, which is liquid and has a black surface and is soluble in carbon disulfide. Asphalt is an organic cementitious material that is waterproof, moisture-proof and anti-corrosion. Asphalt can be mainly divided into three types: coal coke asphalt, petroleum asphalt and natural asphalt

Among them, coal coke asphalt is a by-product of coking. Petroleum bitumen is the residue after distillation. Natural bitumen is stored underground, and some form layers or accumulate on the surface of the earth's crust.

Asphalt is mainly used in coatings, plastics, rubber and other industries, as well as paving roads.

Facilitate construction and open traffic in a timely manner.

OK.

In general, in the paving of asphalt concrete.

The modified emulsified asphalt with a content of 45% to 55% is sprinkled on the cement concrete pavement before, and the bonding of the asphalt concrete and the cement pavement is used to prevent the excessive penetration of the upper and lower layers of water from making the upper and lower layers peel off prematurely, resulting in the displacement and spalling of the asphalt concrete plate.

Non-woven fabrics are mainly pasted with a width of not less than 1 meter (or glass fiber grid) at the transverse joints, longitudinal joints and expansion joints of the original cement pavement to prevent the transverse joints, longitudinal joints and expansion joints of the original cement pavement from being prematurely reflected to the asphalt surface layer and causing premature damage to the pavement. At present, the domestic white and black.

The lower layer of the project (cement pavement and asphalt concrete) generally adopts AC structure.

Fields of application. in civil engineering.

Asphalt is a widely used waterproof material and anti-corrosion material, mainly used in the waterproofing of roofing, ground and underground structures, and the anti-corrosion of wood and steel. Asphalt is also a widely used pavement structure cementing material in road engineering, which can be combined with different composition of mineral materials in proportion to build asphalt pavement of different structures.

Highway is widely used.

1. Asphalt pavement can not be constructed in rainy days, and the rain will damage the asphalt pavement, so that the temperature of the asphalt mixture will drop quietly, which will cause the situation of rolling unreal.

2. Light rain will reduce the temperature of asphalt concrete, mixed with rainwater will cause asphalt concrete can not be cohesed together, mixed with rainwater, after the rainwater is dry, there are countless pores left, and the noisy reeds can not reach the required compactness, which seriously weakens the strength of the pavement.

3. In the construction of asphalt pavement in rainy days, not only the degree of compaction cannot be guaranteed, but also the flatness cannot be guaranteed. In addition, the accumulation of water on the surface of the lower bearing layer will seriously affect the bonding of the two structural layers, form a sliding layer, and cause the premature damage of the pavement structural layer to the lifting belt.

4. Under the condition of moisture, the asphalt pavement is subjected to the repeated action of traffic load and temperature expansion and contraction, and the asphalt film gradually peels off from the surface of the aggregate, which leads to the loss of cohesion between the aggregates and the destruction of the pavement.

Old drivers who have driven on the highway must have experienced, when driving on the asphalt road, the driving noise is significantly smaller, and occasionally encounters a small section of cement road, you will find that the noise of tire friction with the ground is very obvious. From this point of view, asphalt pavement obviously has many advantages over cement pavement.

The pavement belongs to the rigid pavement, and it is necessary to reserve the gap every other distance, so as not to damage the pavement caused by thermal expansion and contraction in the hot summer. The asphalt pavement is a flexible pavement, which is very comfortable to drive on, and there is almost no bumpy feeling.

The laying of cement pavement is more troublesome, and the time taken is also long, if the cement solidification process happens to encounter the scorching sun, special personnel must be arranged to sprinkle water; However, the asphalt pavement is very simple, paved and compacted with a road roller, and it will soon be opened to traffic, and the construction period is much shorter than that of the cement pavement. On the other hand, when the pavement is damaged, the repair of the cement pavement is very troublesome, and the damaged piece needs to be dismantled and re-poured; Asphalt pavement is much simpler, just patch it and pour asphalt on the damaged area.

The cement pavement is impermeable, smooth as a mirror when it rains, and at this time it is extremely easy to slip when driving on the cement pavement at high speed, and it is extremely easy to slip when it encounters a turn or brake, and the evaporation of water on the road surface is relatively slow after the rain stops; Compared with cement pavement, asphalt pavement is much rougher, and has strong water permeability, it is not easy to slip in rainy days, and there is less water, and it is easier to restore the road surface after the rain stops.

It is precisely because of these advantages of asphalt pavement that although the cost of asphalt pavement is much higher, cement pavement is still gradually replaced by asphalt pavement. Not only highways, but also more and more urban expressways and high-grade highways have begun to use asphalt pavement instead of cement pavement.

First, the construction period of asphalt pavement is shorter, as long as it is paved and compacted, it can be opened to traffic, and the cement pavement must be maintained and hardened to a certain extent;

Second, the asphalt pavement is easier to maintain, reducing the economic loss, and the small repair only needs to patch the damaged place, unlike the cement pavement, which needs to be dismantled and re-poured with a broken piece;

Third, asphalt pavement is helpful for driving, because it has better flatness and lower noise, which is also helpful for safe driving.

The asphalt pavement is strong, resistant to changes in temperature, and resilient.

The driving comfort of concrete pavement is not as good as asphalt, and the noise is large, and the later maintenance is troublesome. If it is damaged, it is difficult to repair, and the curing period of the newly poured panel is longer.

Asphalt is a very common building binder material, because it is cheap and has good performance, so many pavements are used, which can have the effect of waterproof and earthquake-resistant.

Asphalt pavement. It is not possible to construct in rainy days, on the one hand, rain will damage the asphalt pavement, and on the other hand, the asphalt mixture.

When the temperature drops, it will be crushed and unsolid.

Under the condition of moisture in the asphalt pavement, the asphalt pavement is subjected to the repeated action of traffic load and temperature expansion and contraction, on the one hand, the moisture gradually invades the interface between the asphalt and the aggregate, and at the same time, due to the effect of hydrodynamics.

The asphalt membrane gradually peels off the surface of the aggregate and causes the loss of cohesion between the aggregates and the destruction of the pavement causes. The main causes of water damage to asphalt pavement are materials, design, construction, soil foundation and base layer, overloaded vehicles, etc.

The weather has an impact on the paving of asphalt pavement, and its impact is not whether it can be constructed, but mainly the quality of pavement paving. We often find that the newly paved road surface will have potholes, which is actually related to the weather when the asphalt is laid. There are several types of unfavorable weather that are not suitable for asphalt pavement.

One is low temperature weather. When the temperature is below 5, the asphalt solidifies quickly, does not stick to the road surface, and cannot be paved.

The second is hot weather.

When the temperature is above 30, the asphalt is not easy to flatten and not easy to pave.

The third is rainy weather. In case of rainy weather, asphalt does not stick to the pavement, can not be paved, even if there is no rain when paving, but within two days after paving, the asphalt is easy to fall off, so that the road surface potholes.

Summary. Concrete pavement can be paved with asphalt, and a layer of adhesive oil must be applied.

This is because the materials of the two are different, and a layer of sticky layer oil is to increase the connection between the upper and lower layers, and the thickness should also be controlled. If there are cracks in the concrete pavement, it is reasonable to repair the old pavement first and then make the matrix, and then lay a layer of fiber mesh on it, and then lay an asphalt layer of no less than 30mm.

Can concrete pavement be directly paved with asphalt?

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Concrete pavement can be paved with asphalt, and a layer of adhesive oil must be applied. This is because the materials of the two are different, and a layer of sticky layer oil is to increase the connection between the upper and lower layers, and the thickness should also be controlled. If there are cracks in the concrete pavement, it is reasonable to repair the old pavement first and then make the matrix, and then lay a layer of fiber mesh on it, and then lay an asphalt layer of no less than 30mm.

Cement concrete pavement can be paved with asphalt concrete, a layer of sticky layer oil must be played in the middle, increase the connection between the upper and lower layers, and the thickness should also be controlled. Under normal circumstances, asphalt concrete pavement is paved on the old cement concrete pavement, and this situation does not require special treatment, but it is necessary to pay attention to the rationality and smoothness of the road surface elevation, because there is a height difference, that is, to make a small gentle slope that extends at the junction. The situation of the same elevation is rare in the actual construction, because the concrete pavement is a hard pavement, while the asphalt concrete pavement is a soft pavement.

If the elevation is required to be consistent, the foundation of the asphalt concrete pavement will be concreted at the junction, so that it can be connected with the cement concrete pavement and increase the longitudinal bearing capacity of the pavement.