Www.sijiate.com Qinhuangdao Sijiate Special Purpose Vehicle Manufacturing Co., Ltd.
[Abstract? Preventive maintenance fog seal technology is an economical, effective and simple road protection measure. It has become a brand-new subject to do preventive maintenance in time for early pavement diseases. At the same time, as a special technology of preventive maintenance, fog seal technology is more and more used in highway maintenance, so fog seal technology is becoming more and more diversified. As a new technology, sand fog seal coat technology not only does not affect the use function of pavement, but also has waterproof and impervious performance.
Keywords: preventive maintenance? Municipal maintenance? Sand and fog seal? waterproof material
Brief introduction of pre-curing technology of sand fog seal coat
Fog seal coat technology is to spray a thin layer of high-permeability modified emulsified asphalt on the asphalt surface by using a special distributor to form a strict waterproof layer, seal the cracks on the pavement, and play the role of waterproof, seepage prevention and pavement protection. As an effective preventive maintenance method, fog seal coat technology can close the micro-cracks on the pavement surface, prevent the pavement from seepage, prevent the pavement from loosening, delay the aging of the original pavement asphalt and improve the pavement appearance.
Sand-containing fog seal coat is an upgrade of fog seal coat technology, which is a mixture of fog seal coat material and sand with modified emulsified asphalt or coal tar asphalt-based materials, clay and polymer additives as the main components. Spraying a thin layer on asphalt pavement with a special high-pressure spraying truck containing sand fog seal coat can not only achieve the original characteristics of fog seal coat, but also delay the aging of pavement, reduce the temperature of asphalt surface layer, maintain the anti-skid performance of pavement and achieve the effect of significantly improving the appearance of pavement.
Three. Technical characteristics and performance of sand fog seal coat
(1) technical features
(1) Effective pre-maintenance construction technology, especially suitable for the early use of pavement life, can achieve the purpose of delaying the occurrence and development of pavement diseases and keeping the pavement in good use at a low maintenance cost, especially suitable for? Used for high-grade or other new highways that have been open to traffic for 2-3 years without obvious diseases.
(2) It can also be used for pavement with severe asphalt aging, and the aging asphalt of pavement can be improved through its own reduction and regeneration characteristics. When the appearance of the road is significantly improved.
(3) Effectively waterproof and improve the anti-skid performance of pavement: mix sand with appropriate particle size evenly with reducing agent, and then spray it on the pavement at high pressure, which not only has the advantages of reducing agent seal coat and fog seal coat, but also makes up for one thing. The fog seal coat has poor anti-skid performance and ensures driving safety.
(2) Specific performance
(1) Anti-skid performance
An important function of pavement is to ensure the safety of users. Under the action of traffic load and natural factors, surface characteristics decay faster than structural characteristics, so preventive maintenance should be adopted to ensure surface characteristics. Therefore, preventive maintenance materials should have good anti-sliding performance.
Sand-containing fog seal coat technology breaks the traditional fog seal coat construction technology. The aggregate is directly put into emulsified asphalt, and the additive with special components is added to make it stably suspended, and then it is evenly sprayed on the road surface through high-pressure equipment, thus eliminating the two steps of sanding and rubber roller rolling afterwards. And because it is completely wrapped by the material, the effect of grinding and rolling is more firm and stable. This maintenance technology of sand-containing fog seal coat greatly improves the defects of the original fog seal coat technology, and the bonding material with high adhesion and aggregate with high wear resistance are fully combined to ensure the necessary anti-skid performance of pavement.
(2) Waterproof performance
The sand mist seal coat is sprayed on the pavement by high-pressure equipment, and quickly forms a film, which can effectively fill the tiny cracks on the surface and go deep into the pavement cracks to prevent the cracks from expanding further. The fiber component contained in the material also greatly improves the ductility of the product itself and avoids the cracking of the material at low temperature in winter. At the same time, Sirma's unique production technology makes the product form a unique molecular structure, which not only ensures the waterproof of the surface layer, but also makes it breathable. When the surface temperature rises, the moisture at the bottom of subgrade is discharged in the form of water vapor, thus avoiding the bulging phenomenon of pavement.
(3) Anti-aging performance
Anti-aging performance is generally reflected in two aspects, that is, the ability of reducing agent to delay asphalt aging and the ability to restore aging asphalt. The protective layer formed by spraying the reducing agent of asphalt into a film is used as a barrier to isolate the destructive factors, so that the asphalt pavement can resist the irradiation of ultraviolet rays and sunlight in the air, protect the unexpired asphalt, and lock the extremely important oil and plasticizer in the asphalt into the asphalt concrete. Moreover, the reducing agent can also cause physical and chemical reaction of surface aged asphalt, change asphalt composition, restore its flexibility and cohesiveness, prevent aging acceleration caused by moisture intrusion, and protect the softening effect of asphalt light oil.
(4) Durability
The asphalt reducing agent contains a special surfactant, which has super bonding performance. It can not only firmly adhere to the original pavement, but also firmly lock the loose aggregate produced by asphalt loss on the original pavement. At the same time, because the material contains mineral components, it also improves its wear resistance and high temperature stability, and the added fiber structure ensures the low temperature crack resistance of the material. Through the use of additives, the products can also resist the corrosion of chemical products on the pavement, especially the snow melting agent commonly used in winter in the north and the oil stains spilled on the pavement, ensuring the pavement to have good performance and surface characteristics for a long time.
(5) Environmental protection performance
In response to the call for energy conservation, emission reduction and low-carbon environmental protection, everyone should set an example and actively advocate. The Sirma asphalt reducing agent used in this project is a water-based sealing fabric which is harmless to the environment, and the organic volatile matter (voc) per liter is less than 150g. Tested by the National Building Materials Testing Center with the high standard of indoor building coatings, it still meets the requirements of environmental protection, indicating that the environmental protection performance is absolutely qualified.
Fourth,? Construction scheme, method and timely measures of major projects
(1) Road surface cleaning
Taking the construction of spraying asphalt reductant on the pavement as the main control line, the determined area is the pavement cleaning operation area, and the operation time is before the construction of asphalt reductant on the pavement. The operation process is as follows:
(1) Determine the construction section and scope.
(2) Enclosure of the working area: The safety guidance and reform operation team shall set the working area according to the traffic guidance and reform plan.
(3) After manually cleaning the current road surface, use an imported blower to purge the road surface.
(4) After the operation, check and accept the completion of the operation project.
(2) Sand fog seal construction:
Determine the daily workload and tasks to be completed according to the maintenance contract period, which lasts for about 4-6 days, and will be postponed under special circumstances. The construction process is as follows:
(1) Construction preparation: Construction personnel and equipment enter the operation area, make good preparations before construction, and cover the existing kerbs and steel guardrails with plastic film for protection.
(2) Cleaning the road surface: use a large manual blower to clean and remove dust, sand, leaves, scraps of paper and other sundries. If there is oil on the road surface, deal with it in advance.
(3) Protection of pavement marking facilities: In order to prevent the construction from polluting the pavement marking, the marking is pasted with customized special adhesive tape (15cm, 20cm wide) to ensure full coverage within the marking range.
(4) Treatment of original pavement diseases: Before construction, the cracks, pits and other diseases of the original pavement should be treated in advance, and the treatment quality should be guaranteed.
(5) Spraying construction of sand mist seal coat: high-pressure spraying equipment is used for spraying construction, and the spraying device should be calibrated before spraying to ensure the spraying pressure and width. In order to fully ensure the spraying pressure and atomization effect, the first layer is sprayed twice, the first time is 1/3 lane width, and the second time is 2/3 lane width, so as to ensure the spraying amount at the intersection of the two places. , neither exposed nor overlapping too thick.
(6) Local repair: For the parts where the equipment is omitted and the spraying amount is too large, local repair shall be carried out by manual cooperation with the special repair cart to ensure the overall effect of the construction section is uniform.
(8) Sand-fog seal coat maintenance: After the construction is completed, relevant personnel shall enclose the operation area with a security cordon to prevent vehicles from entering the construction area by mistake and from rolling the newly paved road. According to the weather temperature and the actual situation on site, it will be cured for about 4-6 hours, and it can be opened to traffic.
Verb (abbreviation of verb) abstract
The main function of sand fog seal coat is to form a protective film on the asphalt pavement surface, bridge the pavement surface, seal the underwater leakage of the pavement surface and reduce the water damage of the pavement. At the same time, it can't form a thick "oil skin" on the road surface, which affects driving safety.
1. The preventive maintenance construction of sand fog seal coat on Zhouhai Road is to spray sand reducing agent on asphalt pavement to make the reducing agent closely adhere to the pavement to form a continuous thin layer and penetrate into the pavement to a certain depth, thus achieving the following preventive maintenance effects:
(1) Seal the pavement pores and tiny cracks to prevent the infiltration of pavement water and prevent the occurrence of pavement water damage;
(2) Improve the pavement appearance.
(3) forming a protective layer on the surface of the pavement to repair the aged asphalt and prolong the service life of the pavement;
(4) Spray fine aggregate to improve the skid resistance of pavement and ensure traffic safety.
2. Reduce the life cycle cost of pavement maintenance.
Sand fog seal is used to seal the underwater seepage of pavement, so as to slow down the aging of pavement and delay the maintenance of pavement. Therefore, after sand fog seal coat construction, its road performance can be evaluated by the following three indicators:
(1) permeability coefficient, and evaluate its bridging and sealing effect on tiny cracks and gaps in pavement;
(2) Macro-structural depth, evaluating whether it will form "oil skin" and affect driving safety;
(3) Friction coefficient, which evaluates the anti-skid performance of the reducing agent itself.
3. The investment in equipment is low, and only one spraying device is needed for sand and fog seal construction, which reduces the investment in construction equipment by at least 50%.
4. Low energy consumption. Sand fog seal coat is a normal temperature construction technology, which does not need heating and insulation during construction, which makes its energy consumption far lower than that of the maintenance technology using hot asphalt.
5. Reduce the impact of construction on normal traffic. Under normal construction conditions, the paving length of reducing agent seal can reach 5 ~ 10 per working day. Kilometers, the construction efficiency is extremely high. Generally, the traffic can be opened 2 ~ 3 hours after the construction of reducing agent seal coat, which has little influence on normal traffic.
6. The construction has little environmental pollution, and the sand mist seal coat is a normal temperature construction process, which avoids the environmental pollution caused by asphalt smoke in the high-temperature asphalt construction site and the health damage to construction workers such as smoking, burning and inhaling carcinogens, greatly improves the construction conditions and reduces the labor intensity.
After the completion of the project, we carried out targeted follow-up observation on the pavement, especially on two additives (sand and oil) of reducing agent.
Sand: When the project is just completed, it is evenly distributed on the road surface, locking loose aggregate. After 1 ~ 2 weeks, the surface sand falls off a little, but it does not affect the anti-skid effect of the pavement. Up to now, the sand and the road surface are integrated and condensed together, and there is no phenomenon of vehicles passing by, which effectively plays a waterproof role.
Oil: This modified emulsified asphalt has strong permeability and high cohesiveness, which effectively continues the aging of pavement. From the completion of the project to now, there has been no oil leakage on the road surface for nearly 60 days, and the pre-maintained road surface of this section feels like new visually.
To sum up, it is not difficult to see that the pre-maintenance technology of sand and fog seal coat has good applicability in highway maintenance, and it has good performance in terms of actual use effect, environmental protection, equipment investment, traffic time and so on, and it is a technology worth popularizing.