Drainage asphalt concrete pavement construction materials
Road construction on material permeability requirements are relatively high, to be able to achieve the safety of the project use standards, asphalt and concrete materials mixed with the use of the stability of the structure and the final use of the effect are very obvious improvement, better drainage of the road surface water, so that it will not affect the final structural stability.
Raw materials used in the basalt, the diameter of the material is relatively small, can be better integrated with cement and other raw materials, to ensure that the use of materials during the better with other raw materials with each other, together to enhance the stability of the use of materials. Raw material selection to consider whether the weathering impact, the surface of the material if there is a dense weathering holes, will lead to the final use of lower standards, permeability increased at the same time the pavement structure strength will be significantly reduced. This feature should be considered during the test.
The coarse material has stronger permeability, but the ratio added should be focused on control, and when collecting raw materials, consider whether they contain impurities, and if there are some other rock material debris, to clean up, so that the phenomenon of unreasonable use of raw materials can be avoided. When the diameter of the rock material is relatively large, to ensure that the shape is similar to unity, take out part of the material, put it into the water and then observe the ability to absorb water, through this method can accurately determine the density of the material and surface weathering.
Asphalt in the high-temperature state will enhance the fluidity, the melting point of the material is judged by test analysis, pavement materials after a period of time, if the surface tension is not enough will lead to the emergence of structural cracks, extensive damage to the pavement.
The choice of asphalt materials with stronger viscosity can avoid such problems, and the construction efficiency will also be significantly increased, and can be integrated together with other rock materials. The mixed material obtained will be a great improvement in both waterproof performance and use standards.
As one of the important materials for pavement construction, it accounts for only 4%. After using it, it can be the structure of the constructed project is more delicate, and the quality is improved after putting it into use, and it is not easy to appear cracks and other damage phenomena. Mineral powder is added to the concrete material, and the permeability of the test part is observed to reach the required standard. The drainage efficiency will also be significantly improved after the project is put into use.
Drainage asphalt concrete pavement construction materials with the design
Program design also has a very serious impact on the quality of the use of road projects, and it is very helpful to strengthen the cooperation between the design and construction program to optimize the drainage performance of the pavement. The design phase can be carried out with reference to the engineering file when considering the materials chosen, fully drawing on experience.
1、Target fit ratio design
Cooperate with the implementation of the construction target, to strengthen the regulatory control of the program. In the target mix ratio, the void ratio, aggregate ratio and asphalt amount belong to the main factors in the mix ratio, pavement construction through the measurement of the actual parameters to ensure that the target mix meets the needs of the actual construction technology, because China lacks effective experience in pavement construction technology, so only through the actual measurement to avoid omissions or mistakes in the design of the target mix ratio.
2、Production ratio design
The design of the production mix ratio is based on the target mix ratio, taking the measurement result of the target mix ratio as the reference result, firstly, the screen is set to ensure that the screen holes are effectively controlled, then the actual mix of production is realized according to the matching ratio of various types of hot materials in the target mix ratio, and finally the relevant standards are used to test the parameters, performance and technical indexes of the mix required for pavement construction.
3、Production ratio verification
The verification of the production ratio is based on the production ratio, firstly, the asphalt mixture is mixed according to the ratio derived from the production ratio, the test section is paved, and various tests are conducted, and finally the standard ratio for production is determined.
Construction technology of drainage asphalt concrete pavement
Drainage asphalt concrete pavement construction technology mainly contains three technologies, which are analyzed to ensure the sustainability of pavement construction.
Mixing technology is mainly affected by the equipment, cycle and modifier. Mixing equipment mainly uses mixing machine, mainly intermittent, in order to prevent the pollution of the surrounding environment to be equipped with dust removal equipment, and at the same time do a good job of mixing and control work, pavement construction in the mixing frequency is high, in order to protect with the moisture content of the aggregate, the humidity must be controlled, first of all, with the humidity difference between the aggregate concentration adjustment, and after the humidity is appropriate, in the same time with other aggregates stored, mixing cycle can be set according to the actual situation of road The mixing cycle can be set according to the actual situation of the pavement construction, the basic project mixing cycle is: dry mixing 9s, wet mixing 44s, up and down to keep within the range of 2s set, the actual mixing of the mixture can be set in accordance with the specific conditions of the aggregate, the current pavement engineering modifier is mainly manually put, the same according to the actual situation to determine the mixing, no specific mixing standards.
Mixing the heating temperature of asphalt, the heating temperature of the aggregate, the factory temperature of the mixture and the temperature of the mixture transported to the construction site are to meet the standard requirements.
2、Transportation of the mixture
The type, number and tonnage of transport vehicles should be considered according to the daily production capacity of the mixing station and the distance from the mixing station.
Transport vehicles should be cleaned in a timely manner, to keep clean, in order to prevent asphalt oil sticking to the box, the bottom and side of the box should be coated with a thin layer of oil and water, the ratio of oil to water is 3:1, in order to prevent asphalt pollution of the surrounding environment, and by the rain and temperature drop fast, transport vehicles should be covered with a shed cloth.
The use of paving technology is mainly to ensure the integrity of materials in pavement construction, paver rammer in construction, under the action of vibration, resulting in the destruction of raw materials, so the use of paving technology to adjust the rammer.
The rammer is divided into the main and vice two, when the main amplitude is taken 5mm, vice amplitude is taken 6mm, belong to the combination of the minimum destructive force on the raw materials, while the paver needs to be reasonably adjusted according to the pavement construction environment before using the paver, for example: adjust the paver fabricator, material level, keep the fabricator inside the mixture to be higher than the rotating material, about 2/3 of the position, while timely measurement of paving temperature, to ensure that the temperature is appropriate, will not Excessive impact on the construction with the material. In the paving technology, the main thing is to ensure the rigor of the construction personnel, into the enclosure for paving compaction work before the construction personnel must keep a distance from the road, to avoid trampling events, affecting the efficiency of paving compaction, resulting in uneven pavement and poor drainage.
Rolling technology in construction needs to have process, in the drainage asphalt concrete pavement construction, take the rubber wheel roller and two-wheel big vibration roller rolling can be (not special circumstances generally close vibration), because the road construction gap is relatively large, easy to cause temperature drop, therefore, the frequency of rolling repeated need to focus on improving, basically in the ordinary rolling about 2 times, can be appropriate according to the basic situation of pavement rolling The implementation of vibration, to ensure that the details of the rolling. Rolling is divided into three processes: the initial pressure, recompacting and final pressure, and the temperature should be strictly controlled in each rolling process.
5、The treatment of joints
Whether it is a longitudinal joint or a transverse joint, it should be handled strictly, otherwise it will cause quality problems and leave safety hazards. For longitudinal joints, in general, hot joints should be used, and if the conditions do not allow it, when hot joints cannot be used, the joints should be cut according to the specification requirements. For the horizontal joints, mainly to control the flatness, if not meet the requirements, and the longitudinal joints take the same method, according to the standard requirements for cutting joints.
With the rapid development of highway engineering construction, drainage asphalt concrete pavement in China has been fully promoted, and its construction process, whether in the selection of raw materials or in the ratio and construction process, there are strict requirements, therefore, it is necessary to protect the construction technology of drainage asphalt concrete pavement, both to improve the drainage effect of asphalt concrete pavement, but also to ensure the continuous drainage of asphalt pavement development.