Why do cracks appear in asphalt pavement?

Asphalt pavement. Cracks may be caused by foundation settlement, which can lead to cracking of the surface layer. There is also a case of temperature cracks, due to the setting of temperature cracks.

Unreasonable, resulting in the temperature effect can not be released, resulting in temperature cracks.

The construction joints are not well treated, the joints are not tight, and the combination is poor.

The asphalt does not meet the quality standards suitable for the climatic conditions and use requirements of the region, resulting in the temperature shrinkage of the asphalt surface course or the temperature fatigue stress (strain) greater than the tensile strength (strain) of the asphalt mixture.

Reflective joints of shrinkage cracks in semi-rigid substrates.

Fill on both sides of bridges, culverts, or passageways creates consolidation or foundation settlement.

After heavy truck load driving or road surface use for a long time, more or less cracks and other diseases will appear, these problems can be prevented and repaired with Huadao road maintenance materials, so as to prolong the service life of the road surface.

I think there are a lot of reasons for this, and they are generally. The foundation sinks, or when the project is first done, it is not very strong, and then it cracks after a long time.

Maybe the asphalt is dry, or it's too sunny, and the roof of my house is broken and repaired with asphalt, and there are cracks, but only a little bit, it doesn't have any effect.

Because of the high temperature in summer, the cement road will crack due to thermal expansion and contraction, and some asphalt roads will be cut piece by piece.

The causes of pavement cracks include subgrade settlement, improper construction in the later stage, excessive pressure on the pavement, and excessive use time.

1. The settlement of the roadbed is uneven.

2. When mixing materials, chemical reactions occur to produce heat, and improper operation during later construction leads to too high internal temperature of the pavement and slow heat dissipation.

3. Cracks caused by too much pressure on the road surface.

4. The road is used for too long, the material is aged, and the hardness of the pavement decreases.

Cement pavement crack repair.

It is of course the best to avoid the problem of frontal cracks in the later stage as much as possible during construction, so as to avoid unnecessary troubles in the later stage, which can not only ensure the life of the road, but also avoid the cost of cracks in the later stage. But if a crack does occur, we can only repair it to ensure the normal use of the road.

Before repairing a road, be sure to find an experienced repairer who is skilled enough to know the operation steps to save a lot of time.

Secondly, according to the size and cause of the road cracks, the appropriate repair method should be selected, such as the adhesion of the repair material, the ability of the repair material to resist shrinkage and aging, or the ability to enhance the compression resistance of the road.

According to these reasons, the construction personnel will choose the corresponding repair technology, select the appropriate repair materials, and the regular repair operation, so as to ensure the thorough repair of pavement cracks.

Causes of cracking slabs The causes of the concrete itself: because the cement concrete pavement is composed of concrete slabs of a certain thickness and width, it has the properties of thermal expansion and cold contraction, so it is easy to warp and cause damage phenomena such as the fracture of the concrete slab. Concrete is not strong enough.

The concrete strength of the general road should reach C30, and the minimum strength should also be C25, if the strength is not enough, it is easy to crack the proportion of cement, sand and gravel used for mixing does not meet the requirements of the raw material control is not strict, and the mud content of sand and gravel is high, which reduces the interfacial adhesion between cement and aggregate. The reason for the roadbed: although the overall strength of the concrete pavement is high and the rigidity is large, the deformation capacity is small, so the compaction degree of the foundation should be uniform.

If the compaction degree of the foundation is uneven, and uneven settlement occurs, it is easy to make the road slab lose its support and hollow out, so as to cause the plate body to break at the place. The foundation flatness is poor, and the foundation flatness does not meet the requirements of the specification, resulting in uneven thickness of the concrete pavement slab. The roadbed is too dry during construction, resulting in dry shrinkage cracks on the surface.

Reasons for temperature: during the construction in the early spring and late autumn of the Weibei Plateau, due to the large temperature difference between day and night, the concrete slab is heated and expands to produce positive warping stress, and the temperature drops to near zero at night, and the concrete slab is cold and shrinks, resulting in negative warping stress, and the positive and negative warping stress alternate with each other, which is easy to cause the fracture of the concrete slab that has not yet been cured and formed, and this kind of joint is generally called a temperature joint. Reasons for construction operations:

The water-cement ratio of the mixed concrete mixture is out of control, and the probability of cracks in the early stage increases. Vibration is not compact, premature demoulding will cause the concrete slab to twist and deform the concrete clinker is discontinuous, suddenly interrupted and the interruption time is more than half an hour to form construction joints, artificially causing cracks in the concrete slab.

1. It is related to the thickness design of the pavement. If the thickness of the pouring does not meet the requirements and exceeds its bearing range, cracks will appear on the surface over time. In addition, it is also directly related to the strength of the ground, if the strength of the foundation is uneven, the compaction is not good, and the uneven settlement is produced, and the weak places of the road surface will produce cracks under the action of vehicle traffic.

2. In addition, it is also related to the quality of concrete, for example, different varieties of cement are selected, mixed use, and the hardening time is different, which is easy to cause cracks. In addition, vibration, that is, when pouring, the vibration is insufficient, and it is easy to appear honeycomb-like pores on the surface of the concrete, which will directly affect the strength in the later stage. 3. Including maintenance will also affect the strength of the pavement, if the maintenance is not timely, it will affect the strength growth, and it is easy to produce large and small cracks in the later stage.

Another reason is caused by temperature changes, the concrete itself has the performance of thermal expansion and cold contraction, and it will be deformed and cracked when affected by the external environment. This type of temperature crack is a crack that expands due to temperature changes.

In-situ crack joint: Cracks that exist at a certain position near the design joint and the construction lap joint, and the position joint is divided into three types: artificial lap joint, cutting joint, and longitudinal and horizontal joint.

Artificial lap joint: lap joint and joint joint of cement concrete pavement slab caused by construction. Caused by construction gaps, delays, etc.

For example, paving machinery shutdown caused by night rest, mechanized construction paving and paving can not transport pavement mixture in time, and construction discontinuity caused by natural factors. Cutting seams:

Failure to comply with the requirements of the specification, the cutting time is too late, the cutting depth is not enough, the spacing between the cutting joints is too long, or the pouring continuation time is long, resulting in the actual tensile stress generated by the concrete shrinkage is greater than the allowable value of the concrete and cracks near the cutting joint. Longitudinal and transverse joints: in the design and construction, the length and width of the single plate are shown according to the specification, and the selection is unreasonable, and in the design joints, due to the inability to timely fill the material or the improper selection of the filling material, the water that leaks into the roadbed freezes and expands or falls into the hard objects of the stones, resulting in the arching and opening of the road surface and destroys.

Construction quality joints: In the construction, due to poor quality control, poor management, untimely maintenance, or even interruption, the construction is not completely in accordance with the construction specifications and design. Cracks caused by water loss In general, 80% of the water content of the concrete will evaporate, and about 20% of the water content is necessary for cement hardening.

When pouring concrete at high temperature, the cement hydration speed is fast, and the water evaporation is fast, so that the plate surface produces tensile stress, the temperature decreases, the bottom of the slab produces tensile stress, and the temperature gradient action makes the pavement slab warp and deform, resulting in cracks; or severe water loss, resulting in dry shrinkage joints. The influence of wind in windy weather accelerates the evaporation of water in concrete, especially on the surface of the concrete panel, and the top and bottom surfaces of the panel produce different hardening and self-shrinking reactions; Cracks are formed due to the ring-breaking force generated by the self-change.

Shrink the cracks, it depends on the specific situation, it is best to have **.

The subgrade settlement depends on the actual situation.

First, in construction, if the asphalt pavement base and soil foundation compaction are not enough, the pavement as a whole or the base layer will be unstable, and under this influence, the asphalt pavement will also lead to insufficient aging strength.

Second, the asphalt pavement soil foundation and base layer are more sensitive to seasonal alternation. For example, in some cold areas, during the freezing and thawing period in winter, due to the intrusion of water and the poor water stability of the subgrade soil, under the action of freezing, the water accumulated in the upper layer of the subgrade freezes, causing the pavement to rise and crack.

Third, because the water temperature conditions in some areas are not good, there will be problems such as soil foundation and pavement base water stability check. After a long time, the moisture content of the roadbed rises sharply, its own strength decreases, and coupled with the driving force, it is very easy to crack.

Fourth, when asphalt highway construction, it is necessary to strictly follow the relevant process to advance, if the construction technology is insufficient, it is likely to affect the adhesion of asphalt highway pavement, resulting in asphalt pavement cracks. In addition, pavement design is also a problem, if the road pavement design lacks serious balance, the pavement is unevenly stressed, which will also be the cause of cracks in the pavement.

The new technology of grout is applied to the construction process of asphalt pavement cracks.

1) Preliminary preparation. Before construction, the slotting machine should be checked to ensure its smooth operation, and if there is a problem, it should be solved in time. Then inspect and record the asphalt pavement, and select the appropriate repair plan with reference to the actual situation.

During construction, Huatong silicone cold repair joint filling glue can be used, which does not need to be heated and has no construction temperature requirements, and can be directly constructed and potted.

2) Material quality selection. Crack filling and repair materials need to meet the requirements of relevant material standards, and silicone, polyurethane and other series of potting compounds can be selected.

First, the durability of the material must be guaranteed to avoid quality problems such as cracks and hardening in a short period of time, which weakens the effect of caulking and repair.

Second, the elasticity and elongation of the material should be good. The change of external temperature will affect the width of the crack, so the use of good joint filling materials can solve the problems of crack width expansion and contraction.

Third, the adhesion of the material should be good, which is to ensure the crack bonding fixation ability and waterproof performance of the material. Fourth, the construction performance of the material should be good, and the self-leveling performance of Huatong silicone joint filling adhesive is high, and there is no need for complex construction effects.

3) After the surface of the grout is dry (1-3 hours), the remaining debris on the asphalt highway pavement can be cleaned up and opened to traffic, and the traffic opening time mainly depends on the external environment and temperature, and the specific situation depends on the local situation.

Asphalt pavement block cracking is the pavement is divided into block criss-cross cracks, some block cracks are due to the transverse cracks of the asphalt layer itself, longitudinal cracks continue to develop, criss-cross formation, some block cracks are due to the reflection cracks caused by the block cracking of the pavement base, and there are temperature fatigue and asphalt aging caused.

Summary. The construction cold joints are not treated well, the joints are not tight, and the combination is poor.

The low temperature deformation resistance of asphalt is poor, which causes the asphalt surface course to shrink and crack at low temperature.

The thickness of the asphalt pavement surface layer is insufficient, and structural cracks are generated under the action of driving load.

Reflection cracks produced by shrinkage cracks in semi-rigid substrates.

If I'm satisfied, you can give me a thumbs up.

Why do cracks appear in asphalt pavement?

The construction cold joints are not treated well, the joints are not tight, and the combination is poor. 2.The low temperature deformation resistance of asphalt is poor, which causes the asphalt surface course to shrink and crack at low temperature.

3.The thickness of the asphalt pavement surface layer is insufficient, and structural cracks are generated under the action of driving load. 4.

Reflection cracks caused by shrinkage cracks in semi-rigid base layersIf you are satisfied, you can give me a thumbs up.

What causes this?

This may be the second case.

Asphalt pavement crack treatment measures:

1. Surface sealing method: suitable for slight cracks with a crack width of less than 2mm.

The asphalt pavement that does not require high flatness can be repaired or treated at the micro-surface by spraying asphalt sprinkling method in the high temperature season, and the emulsified asphalt slurry sealing layer should be used in the low temperature season.

For asphalt pavement with high flatness requirements, a small amount of asphalt with low consistency can be painted along the cracks, and cationic emulsified asphalt should be used in low temperature and wet season.

2. Slotting and filling method: It is more commonly used and is suitable for longitudinal or transverse cracks with a crack width of more than 2mm.

Asphalt pavement is a variety of types of pavement formed by paving and rolling asphalt concrete. Asphalt concrete is a mixture formed by fully mixing asphalt materials with a certain viscosity and appropriate amount of mineral aggregates with a certain gradation.

As an asphalt pavement material, asphalt concrete has to bear the repeated action of vehicle loads and the long-term impact of environmental factors during use. Therefore, asphalt concrete must not only have a certain bearing capacity, but also have good durability to resist the action of natural factors.