1、 What are the characteristics of asphalt concrete?
1. Asphalt pavement has high temperature stability;
2. Asphalt pavement has low temperature crack resistance;
3. The asphalt pavement has water stability;
4. Asphalt pavement shall have fatigue resistance.
2、 How to construct asphalt concrete in Jinan?
The construction of semi flexible pavement mainly involves the paving of the parent asphalt mixture surface layer and the pouring of cement mortar, which are two main stages. Because the design requirements and methods of semi flexible pavements are different from those of ordinary asphalt pavements and involve the process of pouring cement mortar, the construction methods of semi flexible pavements are also relatively different from those of ordinary asphalt pavements.
According to the characteristics of semi flexible pavement mixtures and the experience of implementing semi flexible pavement construction abroad, the key points of each process of semi flexible pavement construction are summarized as follows:
The construction process of porous parent asphalt mixture pavement should include the following five aspects:
1. Mixing, transportation, paving and compaction of porous parent asphalt mixture;
The quality of porous matrix asphalt mixture paving will directly affect the performance of semi flexible pavement. Therefore, special attention should be paid to the quality management of smoothness and other aspects during paving. In addition, in order to prevent the injected cement mortar from penetrating into the base layer below the multi parent asphalt mixture pavement layer, it is necessary to carefully check the density of the base layer before laying, and if necessary, add an isolation layer.
2. Production of cement mortar:
Before adding water, other materials should be mixed for 1-2 minutes until they are uniform, and then water should be added to mix for 2-3 minutes until the materials are uniform and consistent. Cement mortar can be produced. If it is required to achieve a certain landscape effect, it can be mixed with mineral powder by adding a certain component of pigment (toner) (this method is often used in some functional pavements to color the road surface and form a colored road surface).
3. Filling of cement mortar:
Drill core samples to determine the void content of the paved semi flexible pavement parent asphalt mixture. This is used as a parameter to control the amount of cement mortar to be filled and the design of technical indicators, and to control the fluidity of cement mortar to ensure its penetration. Factors such as the depth of penetration, the porosity of the parent open-graded asphalt mixture, and the mortar loss rate are calculated and determined. The loss rate of mortar is generally around 10%.
During rolling, keep the rolling wheel wet. When constructing in a large area, the pouring of cement mortar can refer to the construction methods of semi-flexible pavement in foreign countries, and a special cement mortar spraying truck can be used for spraying and pouring. As the cement mortar spraying truck can spray and mix during the spraying process, it can ensure the fluidity and uniformity of the cement mortar, thereby preventing the deposition of sand in the cement mortar, and the construction quality will be relatively high.
4. Scrape off excess slurry:
After the penetration is completed, use a road rake to remove the cement mortar remaining on the asphalt pavement surface, so as to expose the unevenness of the parent asphalt concrete surface, and prevent the cement mortar from remaining on the pavement surface, which may affect the appearance of the pavement to a certain extent and reduce the skid resistance of the asphalt pavement. If there are special requirements for slip resistance and appearance, quartz sand can be used to polish and remove the remaining cement mortar, which needs to be treated according to the material and construction method.
Alternatively, after the completion of the cement slurry pouring, the surface can be cleaned after the initial setting, and the retarder sprayed on the road surface. Then, before the final setting of the internal cement slurry, the surface cement slurry can be washed clean with water, which can not only ensure the strength of the underlying cement slurry, but also ensure the uniformity of the road surface color. However, until then, personnel and vehicles are prohibited from passing through.
5. Health preservation
The permeable slurry shall be cured for a certain period of time. When the construction temperature is below 30 ℃, there is no need for special curing methods; When the construction temperature is above 30 ℃, it is necessary to use plastic film for curing. The curing time should vary depending on the nature of the grout, and traffic can usually be opened after 2 to 3 days. If early strength cement or early strength agent are used in the mortar, traffic may be opened after a few hours. After the slurry has hardened, traffic can be opened.
This concludes the use characteristics of asphalt concrete and how to construct it. If you have any doubts or needs about this, please feel free to contact us http://www.ycgjglcl.com ！