Cold-mixed and cold-laid durable high-performance asphalt concrete surface layer construction process

Abstract

The invention provides a cold-mixed and cold-laid durable high-performance asphalt concrete surface layer construction process, which is characterized in that emulsified asphalt, aggregate, cement, mineral powder and water are used as raw materials of asphalt concrete, and the raw materials are mixed and quickly demulsified to form high-strength asphalt concrete; comprising the following steps: performing single-part quantitative control on raw materials, and putting the raw materials into an asphalt stirring cylinder in a single dosage for centralized stirring; casually inspecting the materials and then conveying to a construction site; performing gravel seal coat construction and ash removal on the pavement; the method comprises the following steps: spreading modified asphalt and gravels on a road surface, covering 70-80% of the road surface with the modified asphalt, performing integral primary paving on a single road when paving durable asphalt, intermittently supplying raw materials to the single road so that the lowest height of mixed asphalt concrete after primary loose paving is 40-50mm and the highest height is 50-60mm, and performing intermittent secondary paving; by improving the demulsification process and the evaporation process, the strength of the asphalt concrete material is improved, the durability of a paved pavement is remarkably improved, meanwhile, pollution can be reduced, and the environment is protected.

Description

Technical Field

[0001] The invention relates to the field of construction technology, and specifically to a cold-mixed and cold-paved durable high-performance asphalt concrete surface layer construction technology. Background Art

[0002] The demand for hot-mix asphalt mixtures in my country has increased from 225 million tons in 2011 to 450 million tons in 2022. The energy consumption in the construction industry is on the rise. The production of these hot-mix asphalt mixtures will consume about 3 million tons of petrochemical energy. The dust, asphalt smoke, CO2 and harmful gases generated by the production of the mixtures have seriously damaged the air quality. Using cold-mix asphalt mixtures instead of hot-mix asphalt mixtures for various grades of asphalt pavement structure layers can largely solve the problems of petrochemical energy consumption and environmental pollution, while improving the production and construction environment, and has the characteristics of energy saving, emission reduction, environmental protection and low carbon; its feedback in the process is poor durability, insufficient strength, and poor compressive performance, which affects the long-term use of the pavement.

[0003] To achieve the above objectives, the present invention provides a cold-mixed, cold-paved, durable, high-performance asphalt concrete surface construction process, which can solve the problems raised in the above background technology. Summary of the invention

[0004] The present invention adopts the following technical solutions to achieve:

[0005] A cold-mixed cold-paved durable high-performance asphalt concrete surface construction process, wherein the asphalt concrete uses emulsified asphalt, aggregate, cement, mineral powder, and water as raw materials, and the raw materials are mixed and quickly demulsified to form high-strength asphalt concrete, including the following steps:

[0006] S1. Carry out quantitative control of cement, mineral powder, aggregate, water and emulsified asphalt raw materials in single portions;

[0007] S2. Add a single dose of cement, mineral powder, aggregate, water and emulsified asphalt of specified specifications into an asphalt mixing tank for centralized mixing;

[0008] S3. Check the materials. When the mixed materials are brown, without white materials, no liquid flowing, and no cement or mineral powder agglomeration, they can be transported to the construction site.

[0009] S4. Carry out gravel seal construction on the road surface and clean the road surface;

[0010] S5. Spread modified asphalt on the road surface and spread crushed stone simultaneously. The modified asphalt covers 70-80% of the road surface. Spread the modified asphalt manually on the uneven local areas.

[0011] S6. Pave durable asphalt. The single-block road is paved in one go. The lowest height of the mixed asphalt surface layer after paving is 40-50mm, and the highest height of the surface layer is 50-60mm. The paving material supply speed is intermittent. The paving uniform speed can be one of 2.5m / min and 3.5m / min.

[0012] S7, compaction, use a light roller to reciprocate 2-4 times, the compaction standard is 80%, use a heavy roller to reciprocate 4-6 times, the compaction standard is above 95%, and the interval compaction joint is 10cm-20cm;

[0013] S8. Carry out traffic control after the joints are compacted.

[0014] Preferably, in step S6, the loose paving coefficient and loose paving thickness of the mixed asphalt are obtained during the construction of the test section and the paving height is adjusted adaptively. After paving, the mixed asphalt is tested to ensure that the paving thickness and cross slope of the test road surface are the same as those of the construction road surface.

[0015] Each test shall be conducted on no less than two cross sections, with no less than 5 test points on each cross section.

[0016] Preferably, in step S2, the asphalt mixture is centrally stirred using a double mixing tank, and the use temperature of the emulsified asphalt does not exceed 60°C;

[0017] During the mixing process, mineral powder and cement are continuously added to the aggregate, and emulsified asphalt is sprayed simultaneously for mixing.

[0018] Preferably, in step S3, the viscosity of the emulsified asphalt is detected synchronously. When the viscosity is high and pumping is difficult, it is heated appropriately. The water and emulsified asphalt pumps, pipelines, and nozzles must be checked regularly to keep them unobstructed.

[0019] Preferably, in step S3, a dump truck with a discharge angle of more than 35 degrees is used for transportation, and the material transport truck can only load a single batch of mixed strength materials at a time, and must be cleaned after each transportation;

[0020] When cleaning, apply a thin layer of vegetable oil or laundry detergent solution on the floor and side panels of the car, and no liquid should be allowed to accumulate. A film covering should be set on the upper part during the entire transportation process, and the covering should not be removed while waiting for other vehicles to unload.

[0021] Preferably, in step S4 and step S5, the modified asphalt is sprayed in a jet-like manner, the temperature is maintained within the range of 165°C to 170°C, and the synchronous stone sealer is controlled to travel at a speed of 4 km / h and maintain a constant speed;

[0022] The dosage of modified asphalt is 2.0-2.2kg / ㎡, and the amount of crushed stone spread is 11-13m3 / 1000㎡;

[0023] The crushed stone is premixed stone with a size of 9.5 to 19 mm.

[0024] Preferably, in step S5, the thickness is controlled by an elevation control method guided by a wire rope, the wire rope diameter is 2mm-2.5mm, the wire pulling length is 250m-300m, the tensioner tension of the wire rope is 1500N-2000N, and the overlap length of the front and rear two wire ropes is 10m-20m.

[0025] Preferably, in step S6, the loose paving coefficient and loose paving thickness of the test mixture can be tested using a road section, and the loose paving thickness should be tested after each paving operation;

[0026] Each test shall be conducted on no less than two cross sections, with no less than 5 points on each cross section.

[0027] Preferably, in step S6, during the paving process, the elevation of the material level sensor must be well controlled so that the screw feeder in the paving trough is always buried at a height of not less than 3 / 4 of the cold mix asphalt mixture.

[0028] Preferably, in step S7, the joints between the reserved areas of the cold mix asphalt mixture laid first should not be rolled temporarily, so as to serve as the reference surface for the mixture to be laid later; when rolling the rear width, it is advisable to first roll from the edge to the middle, and finally roll across the joints; the longitudinal facades of the joints should be coated with tack coat oil;

[0029] The downward force of the light roller is not less than 13 tons, and the downward force of the heavy roller is not less than 30 tons.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention improves the demulsification and water evaporation process of the asphalt emulsion of the mixed material, so that the asphalt inside the mixed material and the mixed material have better bonding force, and cement is added to the mixed material to facilitate the rapid generation of the demulsification effect, and the strength of the mixed material is improved by the hydration reaction of the cement, and the problem of air formed during the water evaporation process is improved, so that the evaporation gap can be quickly filled;

[0032] By using mixed aggregates in a similar way to secondary tidal flats, the temperature dissipation of the loose inner layer can be accelerated, and the steam generated by the hydration reaction can be quickly removed. The secondary paving method of the upper layer can give the lower layer a certain amount of time to dissipate the temperature. At the same time, it can actively fill the gaps in the loose layer of the bottom layer through automatic horizontal flow. When used in conjunction with a roller, it can also better improve the mixing strength of the two layers, reduce cracking and thin paving problems, better fill the gaps between intervals and enhance the durability and self-strength of asphalt concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the cross-sectional structure of the masterbatch mixture of the present invention;

[0034] Figure 2 This is a schematic diagram of the intermittent simulated surface layer structure of the secondary paving of the present invention; DETAILED DESCRIPTION

[0035] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0036] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly connected by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this article includes any and all combinations of one or more related listed items.

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0039] Please refer to the attached Figure 1 The asphalt concrete uses emulsified asphalt, aggregate, cement, mineral powder and water as raw materials, and the raw materials are mixed and quickly demulsified to form high-strength asphalt concrete, including the following steps:

[0040] Step S1, performing single-portion quantitative control on cement, mineral powder, aggregate, water, and emulsified asphalt raw materials;

[0041] Step S2, adding a single dose of cement, mineral powder, aggregate, water and emulsified asphalt of a specified specification into an asphalt mixing tank for centralized mixing; the mixing plant adopts a "tower-type double-layer structure" to implement a double mixing tank design, and the 1st and 2nd level mixing tanks are arranged vertically up and down and in parallel, and a finished product storage bin is set directly below the 2nd level mixing tank, which not only occupies a small area, but also is easy to package as a whole, and avoids the quality defects of the produced cold mix being transported to the finished product bin for storage through the finished product conveyor belt and then unloaded onto the transport vehicle; the mixing equipment should be equipped with 6 cold material bins, 2 powder bins (1 mineral powder, 1 cement), no less than 2 emulsified asphalt tanks of more than 50 tons and 1 water tank of more than 50 tons, and the mixing production capacity should be no less than 600t / h.

[0042] Step S3, sampling materials, when the sampled mixed materials are brown, without white materials, liquid flow, cement or mineral powder agglomeration, they can be transported to the construction site; use WDB800 double mixing cylinder asphalt mixture mixing equipment for centralized mixing, and accurately measure each specification of materials, mineral powder, cement, water, and emulsified asphalt according to the approved production mix ratio, and the measurement error should be controlled within the specified range;

[0043] The use temperature of emulsified asphalt should not exceed 60℃. When the viscosity of emulsified asphalt is too high and pumping is difficult, it can be heated appropriately. The water and emulsified asphalt pumps, pipes and nozzles must be checked regularly to keep them unobstructed.

[0044] The produced mixture is brown, without white material, liquid flow, cement or mineral powder agglomeration, and good workability. The mixed mixture should not be stored and must be transported to the construction site in time. The material transport vehicle must be cleaned before and after each loading. A thin layer of vegetable oil or washing powder solution should be applied on the bottom and side panels of the vehicle, but no excess liquid should be accumulated at the bottom of the vehicle to prevent the mixture from sticking to the vehicle. When transporting the mixture by car, an opaque quilt or thick canvas must be used to cover the entire vehicle tightly to prevent the mixture from breaking and polluting in the light, being exposed to rain on the way, affecting the construction quality of the mixture or causing waste. The vehicle can loosen the covering before unloading, and the covering does not need to be completely opened during the unloading process. It only needs to loosen and open the tailgate of the vehicle to allow the material transport vehicle to unload naturally and smoothly; the covering must not be removed while waiting for other vehicles to unload.

[0045] Step S4, construct the original roadbed, perform gravel seal construction on the road surface, and clean the road surface; Step S5, spread modified asphalt on the road surface, and spread gravel simultaneously, the modified asphalt covers 70-80% of the road surface, and manually spread the modified asphalt on the uneven local position;

[0046] Step S6, please refer to the attached Figure 2, paving durable asphalt, single-block road integral paving at one time, the lowest height of the mixed asphalt surface layer after paving is 40-50mm, the highest height of the surface layer is 50-60mm, the paving raw material supply speed is intermittent supply, the paving uniform speed can be 2.5m / min and 3.5m / min, one of the walking speeds, the modified asphalt is sprayed, and the temperature is maintained in the range of 165℃~170℃; the crushed stone is spread evenly, with a coverage rate of 70%~80%, ensuring that the crushed stone does not overlap, is not loose, does not pile up, and does not show black; the driving speed of the synchronous crushed stone sealing machine should not be too fast, the spreading speed is controlled within 4Km / h, and the driving speed is maintained at a uniform speed; the amount of modified asphalt is 2.0~2.2kg / ㎡, and the amount of crushed stone is 11~13m 3 / 1000㎡, the crushed stone is 9.5-19mm premixed crushed stone, the paving speed is a timed paving material quantitative increase or quantitative decrease type paving, the intermittent paving thickness test difference is within 10-20mm.

[0047] Step S7, compaction, using a light roller to reciprocate and roll 2-4 times, the compaction standard is 80%, using a heavy roller to reciprocate and press 4-6 times, the compaction standard is above 95%, and the interval compaction joint is 10cm-20cm; Step S8, traffic control after the joint is compacted;

[0048] The principle of improving the strength of the mixture in this process is as follows: the formation of mixture strength is actually a process of asphalt emulsion demulsification and water evaporation. The main component of mixture strength is the bonding force of asphalt, and the main function of cement is to promote emulsification as soon as possible, improve the early strength of the mixture through cement hydration reaction and fill the gaps formed after water evaporation.

[0049] In step S6, the loose paving coefficient and loose paving thickness of the mixed asphalt are obtained during the construction of the test section and the paving height is adaptively adjusted. After paving, the mixed asphalt is tested to ensure that the paving thickness and cross slope of the test road surface are the same as those of the construction road surface; each test should be conducted on no less than two cross sections, with no less than 5 test points on each cross section.

[0050] In step S2, the asphalt mixture is centrally stirred using a double mixing tank, and the emulsified asphalt is used at a temperature not exceeding 60°C;

[0051] During the mixing process, mineral powder and cement are continuously added to the aggregate, and emulsified asphalt is sprayed simultaneously for mixing.

[0052] In step S3, the viscosity of the emulsified asphalt is detected synchronously. If the viscosity is high and pumping is difficult, it is heated appropriately. The water and emulsified asphalt pumps, pipelines, and nozzles must be checked regularly to keep them unobstructed.

[0053] In step S3, a dump truck with a discharge angle of more than 35 degrees is used for transportation. The material transport truck can only load a single batch of mixed strength materials at a time, and must be cleaned after each transportation;

[0054] When cleaning, apply a thin layer of vegetable oil or laundry detergent solution on the floor and side panels of the car, and no liquid should be allowed to accumulate. A film covering should be set on the upper part during the entire transportation process, and the covering should not be removed while waiting for other vehicles to unload.

[0055] In the steps S4 and S5, the modified asphalt is sprayed in a jet-like manner, the temperature is maintained within the range of 165°C to 170°C, and the synchronous stone sealer is controlled to travel at a speed of 4 km / h and maintain a constant speed;

[0056] The dosage of modified asphalt is 2.0-2.2kg / m2, and the amount of crushed stone spread is 11-13m3 / 1000m2;

[0057] The crushed stone is premixed stone with a size of 9.5 to 19 mm.

[0058] In step S5, the thickness is controlled by using a wire rope-guided elevation control method, the wire rope diameter is 2mm-2.5mm, the wire pulling length is 250m-300m, the wire rope tensioner tension is 1500N-2000N, and the overlap length of the front and rear two wire ropes is 10m-20m.

[0059] In step S6, the road section may be used to test the loose paving coefficient and loose paving thickness of the mixture. After each paving operation, the loose paving thickness should be tested.

[0060] Each test shall be conducted on no less than two cross sections, with no less than 5 points on each cross section.

[0061] In step S6, during the paving process, the elevation of the material level sensor must be well controlled so that the screw feeder in the paving trough is always buried at a height of not less than 3 / 4 of the cold mix asphalt mixture.

[0062] In step S7, the joints between the reserved areas of the cold-mix asphalt mixture laid first shall not be rolled temporarily, and shall serve as the reference surface for the mixture to be spread later; when rolling the rear width, it is advisable to roll from the edge to the middle first, and finally roll across the joints; the longitudinal vertical surface of the joint shall be coated with tack coat oil; the downward pressure of the light roller shall not be less than 13 tons, and the downward pressure of the heavy roller shall not be less than 30 tons; the initial compaction shall be performed by two double-steel-wheel rollers of ≥13t for 1 to 2 times (one round trip is one time), and 1 to 2 times of vibration compaction at medium or low gear, followed by the paver for compaction, and a relatively short length of the initial compaction area (30m to 50m) shall be maintained; the secondary compaction shall be performed by no less than two tire rollers of 30t or more (the tire inflation pressure is not less than 0.8MPa, the single wheel load is not less than 3.5 tons, and water can be added) for rubbing and compacting for 4-6 times, so as to basically eliminate the wheel marks. The recompacting should be carried out immediately after the initial compacting, and it is not advisable to stop at will. The total length of the roller rolling section should be as short as possible, usually not exceeding 60m. In addition, final compaction can be carried out, preferably using a double steel wheel roller of ≥13t to perform static compaction 1-2 times. Final compaction should be carried out immediately after the recompacting. If there are no obvious wheel marks after recompacting and the surface is flat, final compaction can be omitted.

[0063] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A cold-mixed and cold-laid durable high-performance surface construction process, characterized in that: The asphalt concrete uses emulsified asphalt, aggregate, cement, mineral powder and water as raw materials, and the raw materials are mixed and quickly demulsified to form high-strength asphalt concrete, including the following steps: S1. Carry out quantitative control of cement, mineral powder, aggregate, water and emulsified asphalt raw materials in single portions; S2. Add a single dose of cement, mineral powder, aggregate, water and emulsified asphalt of specified specifications into an asphalt mixing tank for centralized mixing; S3. Check the materials. When the mixed materials are brown, without white materials, no liquid flowing, and no cement or mineral powder agglomeration, they can be transported to the construction site. S4. Carry out gravel seal construction on the road surface and clean the road surface; S5. Spread modified asphalt on the road surface and spread crushed stone simultaneously. The modified asphalt covers 70-80% of the road surface. Spread the modified asphalt manually on the uneven local areas. S6. Pave durable asphalt. The single-block road is paved in one go. The lowest height of the mixed asphalt surface layer after paving is 40-50mm, and the highest height of the surface layer is 50-60mm. The paving material supply speed is intermittent. The paving uniform speed can be one of 2.5m / min and 3.5m / min. S7, compaction, use a light roller to reciprocate 2-4 times, the compaction standard is 80%, use a heavy roller to reciprocate 4-6 times, the compaction standard is above 95%, and the interval compaction joint is 10cm-20cm; S8. Carry out traffic control after the joints are compacted.

2. A cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1, characterized in that: In step S6, the loose paving coefficient and loose paving thickness of the mixed asphalt are obtained during the construction of the test section and the paving height is adjusted adaptively. After paving, the mixed asphalt is tested to ensure that the paving thickness and cross slope of the test road surface are the same as those of the construction road surface; Each test shall be conducted on no less than two cross sections, with no less than 5 test points on each cross section.

3. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1 is characterized by: In step S2, the asphalt mixture is centrally stirred using a double mixing tank, and the emulsified asphalt is used at a temperature not exceeding 60°C; During the mixing process, mineral powder and cement are continuously added to the aggregate, and emulsified asphalt is sprayed simultaneously for mixing.

4. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1 is characterized by: In step S3, the viscosity of the emulsified asphalt is detected synchronously. If the viscosity is high and pumping is difficult, it is heated appropriately. The water and emulsified asphalt pumps, pipelines, and nozzles must be checked regularly to keep them unobstructed.

5. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1 is characterized by: In step S3, a dump truck with a discharge angle of more than 35 degrees is used for transportation. The material transport truck can only load a single batch of mixed strength materials at a time, and must be cleaned after each transportation; When cleaning, apply a thin layer of vegetable oil or laundry detergent solution on the floor and side panels of the car, and no liquid should be allowed to accumulate. A film covering should be set on the upper part during the entire transportation process, and the covering should not be removed while waiting for other vehicles to unload.

6. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1 is characterized by: In the steps S4 and S5, the modified asphalt is sprayed in a jet-like manner, the temperature is maintained within the range of 165°C to 170°C, and the synchronous stone sealer is controlled to travel at a speed of 4 km / h and maintain a constant speed; The dosage of modified asphalt is 2.0-2.2kg / ㎡, and the amount of crushed stone spread is 11-13m 3 / 1000㎡; The crushed stone is premixed stone with a size of 9.5 to 19 mm.

7. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1 is characterized by: In step S5, the thickness is controlled by using a wire rope-guided elevation control method, the wire rope diameter is 2mm-2.5mm, the wire pulling length is 250m-300m, the wire rope tensioner tension is 1500N-2000N, and the overlap length of the front and rear two wire ropes is 10m-20m.

8. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1 is characterized by: In step S6, the road section may be used to test the loose paving coefficient and loose paving thickness of the mixture. After each paving operation, the loose paving thickness should be tested. Each test shall be conducted on no less than two cross sections, with no less than 5 points on each cross section.

9. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1, characterized in that: In step S6, during the paving process, the elevation of the material level sensor must be well controlled so that the screw feeder in the paving trough is always buried at a height of not less than 3 / 4 of the cold mix asphalt mixture.

10. The cold-mix cold-paved durable high-performance asphalt concrete surface construction process according to claim 1, characterized in that: In step S7, the joints between the reserved areas of the cold mix asphalt mixture laid first should not be rolled temporarily, as the reference surface for the mixture to be laid later; when rolling the rear width, it is advisable to roll from the edge to the middle first, and finally roll across the joints; the longitudinal facades of the joints should be coated with tack coat oil; The downward force of the light roller is not less than 13 tons, and the downward force of the heavy roller is not less than 30 tons.

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