Asphalt Heating and Heating Process Analysis | FEITENG

Introduction

Asphalt is an important construction material, which is widely used in various transportation projects such as highways, railroads and airports. It can not only be used as a pavement material, but also be used for waterproofing, corrosion prevention and sealing in roofing, tunneling, embankment and other projects. In the production and processing of asphalt, heating is a very important process step. This paper will analyze and discuss the asphalt heating and heating process to improve the efficiency and quality of asphalt production and processing.

The principle of asphalt heating

The main principle of asphalt heating is to heat the asphalt to a certain temperature, so that it has a variety of properties required in the process of use. The properties of bitumen are determined by the ratio of the number of aromatic rings to alkyl groups in its structure, the average size of the aromatic rings, the degree of substitution of the aromatic aromatics, and the alkyl grouping. At different temperatures, the interactions between the molecular structure of the bitumen, including the molecular clusters, aromatic aromatic oxygens and alkyl aromatic group composition, etc., will change, resulting in changes in the properties of the bitumen.

At different heating temperatures, bitumen will exhibit different properties. Generally speaking, at lower temperatures, the viscosity of asphalt is higher, viscosity, easy to form a film attached to the solid surface, but its plasticity is poor, easy to crack. As the temperature rises, the viscosity of asphalt decreases, so it is easy to flow at low temperatures, the so-called “winter pavement maintenance asphalt” . At high temperatures, asphalt viscosity is extremely low and fluid, commonly used in summer pavement repair.

The way of asphalt heating

The common ways of asphalt heating are as follows:

Hot oil heating method: The method is to heat the hot oil to a certain temperature by combustion heater or electric heater, and then pass the hot oil to the evaporator through the heat exchanger or stainless steel pipe, and the asphalt is heated in the evaporator. This method has the advantages of high heating efficiency, easy operation and even heating.

Steam heating method: the method is through the boiler will be heated into steam, and then the steam transfer to the evaporator, through the steam on the asphalt heating. The method has a wide range of temperature regulation circle, energy saving and so on.

Electric heating method: the method is through the entity of electric heaters or electric heat trough will be converted into thermal energy to directly heat the asphalt, but the method of low heating efficiency, high cost and other shortcomings.

Precautions for asphalt heating

Heating temperature: thermal oil heating and steam heating are indirect heating methods, the heating temperature of asphalt will be affected by many factors, such as heating medium temperature, heat transfer surface area, asphalt flow rate, etc., so the heating temperature should be adjusted according to the specific circumstances.

Heating time: heating time is also an important factor affecting the properties of asphalt. Generally speaking, the heating time is too long, will affect the quality of asphalt, but the heating time is too short will lead to asphalt performance is not enough, so need to be adjusted according to the actual situation.

Heating uniformity: in the asphalt heating should try to ensure uniform heating to avoid the appearance of “scorched” or “melt through” and other phenomena. Should pay attention to steam heating, should be used to gradually increase the heating method, to avoid a sharp rise in temperature, which may cause the asphalt bubbles, physical properties of the damage.

Conclusion

Asphalt heating and heating process is an essential step in the production and processing of asphalt. Through the analysis in this paper, it can be found that different heating methods have different effects on the quality and performance of asphalt. Therefore, in the process of asphalt heating, attention should be paid to factors such as heating temperature, heating time and heating uniformity to ensure the stability of asphalt properties and improve the production efficiency.