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Thermal conductivity

The heat exchange inside the pavement structure and between the pavement and the roadbed is mainly completed through heat transfer. The temperature of the asphalt pavement produced by cable asphalt manufacturers is higher than that of the roadbed during the day, and the upper temperature of the asphalt layer is higher than the lower temperature. At this time, the temperature is transferred from the upper structure to the lower structure, causing the upper temperature to decrease and the lower temperature to increase. At night, the temperature of the upper structure is lower than that of the lower structure, and at this moment, the temperature is transmitted from the lower structure to the upper structure. This thermal conduction process occurs throughout the entire road cycle, causing the road temperature to constantly change.

Thermal convection

Thermal convection is a phenomenon in which heat is transferred from one part of space to another through a moving medium. Newton's cooling rule states that when there is a temperature difference between the surface of an object and its surroundings, the amount of heat lost per unit of area per unit of time is proportional to the temperature difference. The proportionality coefficient is called the heat transfer coefficient. The heat transfer between asphalt pavement and surrounding air is carried out through thermal convection.

It can be seen that the amount of heat conducted by thermal convection between asphalt pavement and air is related to the temperature difference between the pavement and air, as well as the thermal convection coefficient between the pavement and air. The thermal convection coefficient is related to factors such as fluid type and phase transition.

thermal radiation

Objects in nature emit thermal radiation outward, and cable asphalt manufacturers expose themselves to radiation from other objects. When the radiation and received radiation remain normal, the radiation of the object changes to zero. As for asphalt pavement, it is not only exposed to solar radiation, but also absorbs long wave radiation from the atmosphere. The atmosphere exchanges heat through thermal radiation.

The radiation between objects depends on the surface temperature and radiation coefficient, and conforms to the Stefan Boltzmann rule.

Factors affecting temperature effects

Atmospheric temperature

Asphalt pavement is in direct contact with the atmosphere, and the atmosphere and surface form a convective heat transfer system, so the temperature of natural asphalt pavement is most affected by atmospheric temperature. As the atmospheric temperature rises, the asphalt pavement absorbs heat and then travels through the pavement structure temperature; Similarly, when the atmospheric temperature is lower than the road surface temperature, the asphalt pavement will declare a decrease in heat and temperature. Due to the continuity of the heat absorption and dissipation process of the asphalt pavement, the change in asphalt pavement temperature lags behind the change in atmospheric temperature.

solar radiation

The sum of direct solar radiation and scattered radiation in the sky is the total solar radiation, which is short wave thermal radiation. When the total solar radiation reaches the road map, most of it is absorbed and converted into heat in the road structure; Cloud conditions, road surface characteristics, precipitation, snowfall, and other factors can affect the total amount of solar radiation absorbed and reflected by road structures.

Humidity and wind speed

Atmospheric humidity is the degree to which the water vapor content in the atmosphere is separated from the fullness of the atmosphere, usually expressed as a percentage of relative humidity. If you have any other questions, please refer to the official website of the cable asphalt manufacturer or contact us directly.