In the process of asphalt pavement construction, the important properties of asphalt mixture materials mainly include: water stability, fatigue resistance, high temperature stability and durability. In the ratio of asphalt mixture, in order to increase the high-temperature stability of asphalt, it is necessary to increase the aggregate particles and reduce the amount of oil used, but large particles are likely to cause cracks on the road surface and poor durability;
To further overcome the problem of cracks, it is necessary to use a larger amount of asphalt with a higher penetration and a finer mixture, but at the same time, rutting problems will also occur in high temperature seasons;
In order to ensure the roughness of the asphalt pavement, asphalt with better anti-skid performance should be used; in order to ensure the durability of the asphalt pavement, the proportion of asphalt should be determined according to the climate, temperature, terrain and other conditions of the road construction area.
The proportioning process of hot mix asphalt generally includes three main aspects:
Target mix design, production mix design and production mix verification.
In the process of hot-mix asphalt mixture, it is necessary to select materials that meet the technical specifications, make full use of previous road construction experience, and design the amount of asphalt mixture and material varieties through the corresponding mix ratio to ensure the ratio of the mixture quality.
At the same time, the Marshall test must be carried out at each stage of the mix ratio design, and the ratio should be set according to the corresponding specifications of the “Technical Specifications for Construction of Highway Asphalt Pavement”. During the setting process, each asphalt mixing machine must be strictly Do a good job in the design of the asphalt mixture ratio according to the three stages of target mix ratio design, production mix ratio design and trial mix and trial pavement mix ratio adjustment.
During the mixing process of asphalt mixture, the following points should be paid attention to:
First of all, it is necessary to choose a suitable mixing site, which is generally carried out in the mixing site;
Secondly, in the proportioning of asphalt mixture, stirring should be carried out according to the mixing ratio in the room to ensure the appropriate amount of asphalt, mixing time and heating temperature, so as to ensure the quality of asphalt mixture;
Thirdly, in the process of asphalt mixture mixing, it is necessary to mix according to the batching list to ensure the heating temperature of the asphalt and various materials, ensure the uniformity of mixing, and prevent the occurrence of whitening, lumps, and separation of thickness;
Fourth, after the mixing work is completed, relevant technical personnel must take samples to test the amount of asphalt composed of asphalt mixture and mineral material gradation. If the asphalt mixture is found to be inconsistent with the requirements, it should be adjusted in time to ensure that the mixture normal use.