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CN-117431796-B - Instant asphalt concrete thin layer paving construction process

CN117431796BCN 117431796 BCN117431796 BCN 117431796BCN-117431796-B

Abstract

The invention relates to an instant heating type asphalt concrete thin layer paving construction process, which is characterized in that an instant heater is additionally arranged on a paver to secondarily heat a thin layer paving asphalt mixture, and simultaneously, a contact area of a new paving layer and an old paving layer is instantly heated, so that on one hand, the cooling speed of the thin layer paving asphalt mixture is delayed, more compaction operation window time is striven for, on the other hand, thermal contact is formed between the new paving layer and the old paving layer, more firm hot melt bonding is generated, and a traditional poor cold and hot contact bonding mode between the new paving layer and the old paving layer is replaced. Compared with the prior art, the invention has the advantages of reduced construction cost, low heating energy consumption, good construction quality and convenient use, and can further promote the popularization and application of the hot-mix asphalt mixture thin layer paving technology in road construction.

Inventors

  • SUN LIJUN
  • SONG XINYI
  • ZHANG HONGCHAO
  • DU XIAOBO

Assignees

  • 同济大学

Dates

Publication Date
20260508
Application Date
20231010

Claims (7)

  1. 1. An instant asphalt concrete thin layer paving construction process is characterized by comprising the following steps: s1, preparation of construction: s1-1, preparing an asphalt mixture suitable for thin layer pavement construction, wherein the asphalt mixture is a hot-mix asphalt mixture, and the raw materials of the asphalt mixture comprise coarse aggregate, fine aggregate, filler, asphalt or modified asphalt and wood or mineral or polyester fiber, wherein the mixing temperature of the asphalt mixture is 160-180 ℃, and the thickness of the thin layer pavement is 1.0-2.5 cm; s1-2, analyzing and evaluating road surface conditions of an original road surface or a lower lying layer; s1-3, preparing construction equipment, and hanging an instant heater on an asphalt paver, wherein the instant heater is a strip-shaped instant heater which can be spliced; the instant heater is arranged between a spiral distributor of the asphalt paver and a rear wheel baffle of the crawler belt, is provided with a heating control system and is used for heating the thin-layer pavement asphalt mixture and the original pavement or the lower lying layer; the length of each instant heater is 1m or 2m, an extensible splicing design is adopted, and when the instant heaters are installed and hung, a corresponding number of instant heaters are installed according to the width of actual paving operation, so that the pavement heating requirement of the corresponding width is met; S1-4, based on the analysis and evaluation results in the S1-2, combining engineering requirements, site climate and environmental conditions, paving a test section according to a primary construction scheme, performing quality detection, adjusting the primary construction scheme according to the test results, and determining a final construction scheme; s2, site construction: s2-1, adjusting the proportion of aggregate, filler and modified asphalt in the mixture according to the thin layer paving thickness designed by the final construction scheme in S1, calibrating and adjusting a mixer, controlling the heating temperature of the modified asphalt and the aggregate, and controlling the delivery temperature of the asphalt mixture; s2-2, transporting the mixture by adopting a dump truck, and detecting the delivery temperature and the arrival temperature of the asphalt mixture; s2-3, paving by adopting a paver with a hanging instant heater, and synchronously heating an original pavement or a lower lying layer and secondarily heating and paving the thin-layer paving asphalt mixture; before paving, preheating a screed plate and an instant heater, and coating anti-sticking agents on a receiving hopper and a screw feeder, wherein the paving temperature is 160-170 ℃; The heating temperature of the original pavement or the lower lying layer is provided with indexes and standards, specifically, the instant heating temperature of the area to be contacted with the thin layer pavement hot-mix asphalt mixture of the original pavement or the lower lying layer is 120-180 ℃ so as to realize melting of residual pavement or spreading asphalt with a sticky layer and improve interlayer bonding strength; The secondary heating temperature of the asphalt mixture paved by the thin layer is provided with indexes and standards, and particularly, the mixture is heated for the second time in the process of sliding downwards along the slope of the instant heater, and the temperature is raised to 160-180 ℃ so as to prolong the time of the operation window for paving and rolling the thin layer, and the rolling compactness of the thin layer pavement is effectively ensured under the low-temperature condition in spring and autumn; S2-4, rolling the paved working surface by using a road roller; s2-5, detecting and accepting the construction road section according to the characteristics of thin layer pavement and the pavement service performance and combining the acceptance standard of the asphalt concrete pavement; and after the final pressure of S2-6 is finished, opening traffic after the road surface is cooled to below 50 ℃.
  2. 2. The instant heating type asphalt concrete thin layer paving construction process according to claim 1 is characterized in that in S1-2, the analysis and evaluation of the condition of the original pavement or the underlying pavement surface comprise disease analysis, condition evaluation and road surface asphalt residue condition evaluation; The road table asphalt residual condition evaluation comprises the following steps: S1-2-1, selecting sampling points, namely, randomly sampling construction road sections at multiple points, wherein the sampling frequency is selected according to the road section area, and the sampling frequency is not less than 5 points per kilometer, and the sampling points comprise the middle of a traffic lane, a track belt, road shoulders and the junctions of adjacent lanes; s1-2-2 sampling, namely simply cleaning the original road surface, removing impurities with obvious surface, blowing dust, and photographing the clean and dry original road surface; S1-2-3, evaluating the surface condition of the original road surface by means of image analysis software, taking the aggregate bare area percentage as an index, simply averaging the evaluation values of all points of the original road surface to obtain an evaluation value of the aggregate bare area percentage of the original road surface, and providing a corresponding original road surface spreading adhesive layer treatment mode according to the evaluation result.
  3. 3. The instant asphalt concrete thin layer paving construction process according to claim 1, wherein in S2-1, the heating temperature of the modified asphalt is 160-170 ℃, the heating temperature of the aggregate is 180-190 ℃, and the leaving temperature of the mixture is 165-175 ℃.
  4. 4. The instant heating type asphalt concrete thin layer paving construction process according to claim 1, wherein in S2-2, the dumper is clean, provided with a metal bottom plate, a heat preservation layer around a carriage and a covering layer on the top of the carriage; And (3) detecting the temperature by adopting a thermometer, so that the factory temperature of the mixture meets 165-175 ℃ and the factory temperature is not lower than 150 ℃.
  5. 5. The instant asphalt concrete thin layer paving construction process according to claim 1, wherein in S2-4, when in rolling, the road roller presses a new layer for 15cm, gradually shifts obliquely to miss the new layer and then rolls with the newly laid mixture, and then longitudinal rolling is changed to smooth and compact; the vertical seam is processed, the non-compacted mixture at the seam is removed by milling and trimming, the horizontal seam is a vertical flat seam, and the end part is cut off by the line center line.
  6. 6. The instant asphalt concrete thin layer paving construction process according to claim 1, wherein in S2-5, the acceptance process needs to satisfy the following conditions: s2-5-1, the surface of the road is flat and uniform, and the phenomena of oil flooding, loosening, cracking and obvious segregation are avoided; S2-5-2, wherein the longitudinal joint is tight and smooth, and if an emulsified asphalt bonding layer is arranged, the emulsified asphalt of the bonding layer cannot be sprayed in a lap joint manner; s2-5-3, paving the thin layer, closely attaching the thin layer to the curb and other structures, and avoiding water accumulation or water leakage; S2-5-4, wherein the measured quality control standard comprises thickness, compactness, flatness, water seepage coefficient, friction coefficient and construction depth; S2-5-5, namely sampling a core by drilling, and carrying out a drawing test and a shearing test on the core sample, wherein the drawing strength is greater than 0.7Mpa, and the shearing strength is greater than 1.0Mpa.
  7. 7. The instant asphalt concrete thin layer paving construction process according to claim 1, wherein the operation control mode of the heating control system is divided into a manual control mode and an automatic control mode so as to adapt to different construction conditions, specifically: In the manual control mode, an operator manually sets the current power P of the instant heater on a control panel and manually adjusts the current power P at any time, wherein in the manual control mode, the instant heater generates heat according to the set power; The automatic control mode provides mode options suitable for various operation types, an operator can set an automatic operation mode according to construction requirements, and various operation parameters including a system reference paving speed V, heating power P and various temperature feedback parameters can be specifically set, so that real-time calculation and adjustment can be performed, and synchronous linkage of the instant heater and thin-layer paving operation can be realized.

Description

Instant asphalt concrete thin layer paving construction process Technical Field The invention belongs to the technical field of road engineering, and particularly relates to an instant heating type asphalt concrete thin layer paving construction process. Background The pressure on resource shortages and environmental degradation is increasing today and sustainable development faces serious challenges. In order to actively construct a resource-saving and environment-friendly society, the transportation department is greatly promoted to construct a green road nationwide, so that the road construction level is required to be comprehensively improved in aspects of controlling resource occupation, reducing energy consumption, reducing emission pollution and the like, and the thought of strengthening the construction and the restoration is required to be focused on the cost of the whole life cycle. The new road construction and maintenance mileage base of China is large, and the road construction and maintenance mileage base is still rising year by year, so that the reduction of engineering cost and the consumption of resources such as natural stone, petroleum asphalt and the like are long-term urgent problems to be solved in the field of road engineering, and the reduction of the thickness of an asphalt surface layer is a development trend of the future road industry. Compared with the traditional asphalt anti-skid wearing layer with the thickness of 4cm, the paving thickness of the thin layer is only 1-2.5 cm, the material cost is saved by 40% -70%, and the manufacturing cost is obviously saved. In addition, the thin layer pavement can partially replace the function of the traditional asphalt anti-skid wearing layer, so that the flatness and travelling comfort of the old pavement can be restored, and the service life of the pavement is prolonged, therefore, the thin layer pavement technology is increasingly applied, and the thin layer pavement technology can be used for the surface layer construction of newly built roads and the maintenance engineering of repairing micro cracks on the road surface in the preventive maintenance of various roads, is particularly suitable for the major and middle maintenance engineering of asphalt pavement, and is an inexpensive and efficient means for restoring the appearance and flatness of the pavement. However, the asphalt concrete can be only mixed and heated to 160-180 ℃ due to the heat resistance of the asphalt material, the heat capacity of the asphalt concrete is about 837-921J/(kg· ℃), and the thickness of the thin layer pavement is only 1-2.5 cm. Therefore, compared with the natural environment temperature, the heat reserve of the construction operation of the thin layer pavement layer is only 20-50 kJ/m 2, the thickness of the thin layer pavement is small, the heat preservation capability is weak, the thin layer pavement layer is influenced by the factors such as the environment temperature, wind, heat conduction of the lower lying layer and the like on the construction operation site, the thin layer pavement layer rapidly dissipates in two directions of air and an old pavement, and the self temperature falling speed is higher than that of the thin layer pavement layer. In addition, since the temperature of the asphalt concrete thin layer is rapidly decreased, the viscosity of asphalt is rapidly increased with the decrease of temperature, the asphalt concrete loses fluidity more rapidly, the compaction window time is shortened, and the demands on the construction organization and the compaction speed are increased. In practice, the current thin layer pavement can be only carried out under the conditions of summer season and precise organization, otherwise, compaction is difficult, and the construction quality is ensured. In addition, the temperature difference between the new layer of the hot paving and the old lower lying layer with lower temperature is more than 100 ℃, even if the new layer continuously transfers heat to the lower lying layer, the temperature rising range of the lower lying layer is still limited and is insufficient to reach the degree of hot melting of the contact surface, so that the cold bonding problem between the new paving layer and the old paving layer is long-lasting, and the strength of the cold bonding problem is lower. Compared with the common asphalt layer, the hot-mix asphalt mixture thin layer has the advantages of less total heat reserve, quick cooling, more prominent cold adhesion problem between new and old pavement layers, failure in forming good adhesion on the interlayer contact surface, easy occurrence of structural layer separation, and practically manifesting as pavement diseases such as particle falling, peeling and the like. In summary, the asphalt concrete thin layer paving technology has the advantage of low manufacturing cost, gradually becomes the development trend of future road construction and maintenance technology, a