CN115594445A - Interweaved modified asphalt concrete - Google Patents
Interweaved modified asphalt concrete Download PDFInfo
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- CN115594445A CN115594445A CN202211282830.9A CN202211282830A CN115594445A CN 115594445 A CN115594445 A CN 115594445A CN 202211282830 A CN202211282830 A CN 202211282830A CN 115594445 A CN115594445 A CN 115594445A
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- 239000002131 composite material Substances 0.000 claims abstract description 98
- 239000000654 additive Substances 0.000 claims abstract description 27
- 230000000996 additive effect Effects 0.000 claims abstract description 25
- 229920000642 polymer Polymers 0.000 claims abstract description 24
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- 238000002156 mixing Methods 0.000 claims description 41
- 238000012360 testing method Methods 0.000 claims description 34
- 238000000034 method Methods 0.000 claims description 27
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- 238000013461 design Methods 0.000 claims description 22
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Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B26/00—Compositions of mortars, concrete or artificial stone, containing only organic binders, e.g. polymer or resin concrete
- C04B26/02—Macromolecular compounds
- C04B26/26—Bituminous materials, e.g. tar, pitch
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B16/00—Use of organic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of organic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B16/04—Macromolecular compounds
- C04B16/06—Macromolecular compounds fibrous
- C04B16/0675—Macromolecular compounds fibrous from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- C04B16/0683—Polyesters, e.g. polylactides
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/18—Waste materials; Refuse organic
- C04B18/24—Vegetable refuse, e.g. rice husks, maize-ear refuse; Cellulosic materials, e.g. paper, cork
- C04B18/26—Wood, e.g. sawdust, wood shavings
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
- E01C7/00—Coherent pavings made in situ
- E01C7/08—Coherent pavings made in situ made of road-metal and binders
- E01C7/10—Coherent pavings made in situ made of road-metal and binders of road-metal and cement or like binders
- E01C7/14—Concrete paving
- E01C7/142—Mixtures or their components, e.g. aggregate
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/0075—Uses not provided for elsewhere in C04B2111/00 for road construction
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/34—Non-shrinking or non-cracking materials
- C04B2111/343—Crack resistant materials
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Structural Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Civil Engineering (AREA)
- Wood Science & Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
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Abstract
The invention discloses interweaving modified asphalt concrete, which comprises interweaving composite fibers and asphalt concrete; the interwoven composite fiber comprises lignin fiber, polyester fiber and polymer composite additive; the lignin fiber, the polyester fiber and the polymer composite additive are compounded and blended to form interwoven composite fiber, and the interwoven composite fiber is blended in the asphalt concrete and plays a role in comprehensively improving the performance of the asphalt concrete pavement. The lignin fiber has higher oil absorption rate, can adsorb and stabilize asphalt, and improves the durability of asphalt concrete. The polyester fiber is added into the asphalt mixture to play a role of reinforcing ribs, and the low-temperature crack resistance of the asphalt concrete can be obviously improved. The polymer composite additive can improve the viscosity of asphalt, thereby improving the high-temperature performance of asphalt concrete and enhancing the high-temperature rutting resistance of an asphalt concrete pavement.
Description
Technical Field
The invention relates to asphalt concrete, in particular to interweaved modified asphalt concrete, and belongs to the technical field of concrete asphalt material improvement.
Background
The traditional asphalt concrete surface layer construction has the characteristics of poor high-temperature stability, low-temperature crack resistance and poor water stability.
Chinese patent 201310487484.2 proposes a construction process of an interwoven composite fiber modified asphalt concrete surface layer, which specifically comprises the following steps: the method comprises the following steps: mixing the interweaved modified asphalt mixture to weigh ore aggregate, mineral powder, interweaved composite fibers and matrix asphalt, wherein the addition method of the interweaved composite fibers adopts a dry process; step two: transporting the interwoven modified asphalt mixture by using a transport vehicle, wherein the transport vehicle is provided with a heat-insulating layer and a waterproof layer; step three: the interwoven modified asphalt mixture is paved by a paver continuously and at a constant speed; step four: rolling and rolling the interwoven modified asphalt mixture according to three stages of initial pressing, re-pressing and final pressing, wherein the initial pressing adopts the static pressure of a 12-ton double-steel-wheel road roller, the re-pressing adopts four 12-ton double-steel-wheel road rollers for starting vibration and rolling, and the final pressing adopts the static pressure of the 12-ton double-steel-wheel road roller for polishing and collecting the surface; step five: the seam treatment is used for compacting the longitudinal seam and the transverse seam respectively; step six: and (4) maintaining and traffic control, and opening traffic when the surface temperature of the mixture is lower than 50 ℃ after the paved layer is completely and naturally cooled.
Chinese patent 201420621811.9 provides a modified asphalt mixture pavement, comprising: modified asphalt surface course, seal coat, permeable layer and base course; the base layer comprises an asphalt stabilized macadam upper base layer and a cement stabilized soil subbase layer; the cement stabilized soil subbase layer comprises a steel bar framework and cement stabilized soil filled in the steel bar framework; the modified asphalt surface layer comprises a modified asphalt anti-skid surface layer, a high-strength modified asphalt middle surface layer and a high-strength modified asphalt lower surface layer from top to bottom.
In order to comprehensively solve the problems of the asphalt concrete surface layer, the invention provides a composite modified additive material for comprehensively improving the performance of the asphalt concrete pavement, three or four different types of externally-doped modified materials are compounded according to different proportions, the respective pavement performance improving effect points are utilized to comprehensively modify the asphalt mixture, and the interwoven modified asphalt concrete surface layer construction method is formed.
Disclosure of Invention
The invention aims to provide an interwoven modified asphalt concrete, wherein interwoven composite fibers added in the interwoven modified asphalt concrete are composed of three raw materials, namely lignin fibers, polyester fibers and polymer composite additives, and the three external admixtures have respective characteristics on the improvement effect of the performance of an asphalt concrete road.
The technical scheme adopted by the invention is that the interweaved modified asphalt concrete comprises interweaved composite fibers and asphalt concrete; the interweaved composite fiber accounts for 0.2-0.5% of the total mass of the asphalt mixture (namely the total mass of the interweaved composite fiber and the asphalt concrete); the interweaving composite fiber comprises lignin fiber, polyester fiber and polymer composite additive; lignin fiber: polyester fiber: the polymer composite additive comprises the following components in percentage by mass 2; the lignin fiber, the polyester fiber and the polymer composite additive are compounded and blended to form interwoven composite fiber, and the interwoven composite fiber is blended in the asphalt concrete and plays a role in comprehensively improving the performance of the asphalt concrete pavement.
Further, the asphalt concrete includes hot asphalt and aggregates, the aggregates being divided into coarse aggregates and fine aggregates; before the interwoven composite fibers are added into hot asphalt, the interwoven composite fibers are dry-mixed with aggregate. In the dry mixing process, polyester fibers and lignin fibers in the interwoven composite fibers are scattered by the aggregates and uniformly dispersed into the coarse aggregates and the fine aggregates, and the polymer composite additive generates plastic deformation under the coupling action of a stress field and a temperature field, one part of the polymer composite additive is adhered to the aggregates, and the other part of the polymer composite additive is broken and dispersed. After the hot asphalt is added, the lignin fiber dispersed in the aggregate adsorbs and stabilizes the asphalt, the polyester fiber plays a role in increasing viscosity and resisting cracking, and the polymer composite additive particles are swelled, so that the aggregation structure composition of the asphalt is changed, and the viscosity is increased. The three raw materials in the interweaved composite fiber complement each other and act together to improve the pavement performance of the asphalt concrete.
Further, in the mix proportion design of the interwoven modified asphalt mixture, the mix proportion design of the interwoven modified asphalt mixture comprises a target mix proportion design stage, a production mix proportion design stage and a production mix proportion verification stage. In the stage of designing the target mixing ratio, the mixing amount of the interwoven composite fibers is 0.2-0.5% of the total mass of the asphalt mixture, and the preferred mixing amount is 0.3%. In the design stage of production mix proportion, the mixing mode of the interwoven composite fibers adopts dry mixing, the interwoven composite fibers and aggregates are firstly dry-mixed for 60s, so that the interwoven composite fibers are uniformly dispersed in coarse aggregates, and then hot asphalt is added and mixed for 60s; the fine aggregate comprises mineral powder, and the mineral powder is added and mixed for 60s; the total mixing time for dry mixing is 3min. In the production mixing proportion verification stage, the aggregate gradation and the hot asphalt dosage in the interwoven modified asphalt concrete are determined by the mixing proportion design.
Furthermore, the temperature of dry mixing in the test process is controlled as follows, the heating temperature of the coarse aggregate in the test step of the mix proportion design process is set to be 180-190 ℃, the heating temperature of the hot asphalt in the test step of the mix proportion design process is set to be 150-160 ℃, and the mixing temperature of the asphalt mixture in the test step of the mix proportion design process is 165-175 ℃. The temperature of the mixed asphalt mixture in the test step of the mix proportion design process is 160-170 ℃, and the compaction temperature of the mixed test piece in the test step of the mix proportion design process is 165 ℃.
Further, in the target mix design stage:
1) Selecting a target coarse aggregate grading.
And selecting the target coarse aggregate gradation according to the mixture type determined by the pavement design.
2) And calculating the ratio of various coarse aggregates to fine aggregates.
And (3) carrying out a screening test on the coarse aggregate and the fine aggregate, measuring the relative density of the mineral aggregate of various coarse aggregates and fine aggregates and the particle composition of various mineral aggregates, and determining the proportion of various coarse aggregates and fine aggregates when the requirements of a grading curve are met.
3) And determining the optimal hot asphalt dosage.
And determining the optimal hot asphalt dosage of the interweaved modified asphalt mixture by adopting a Marshall test method. Preparing Marshall test pieces by taking the preliminarily drawn target hot asphalt dosage as a median and changing the hot asphalt dosage up and down at the ratio interval of 0.5 percent, wherein the number of the Marshall test pieces is not less than 5; and (3) measuring the stability, the flow value and the density of the Marshall test piece by using a Marshall tester at the test temperature and the test time, and calculating the void ratio, the asphalt saturation and the aggregate gap ratio. Respectively drawing relation curves of the hot asphalt consumption, the density, the stability, the flow value, the void ratio, the hot asphalt saturation and the mineral aggregate void ratio according to the test results and the calculation results, determining the optimal hot asphalt consumption according to the relation curves by a Marshall test method, adjusting the gradation if the optimal hot asphalt consumption cannot meet the requirements, carrying out the batch design again, and carrying out the Marshall test until all indexes can meet the requirements.
Further, in the design stage of the production mix proportion, according to the proportion of various aggregates determined by the target mix proportion, sampling materials entering each hot bin after secondary screening by a mixer, screening, determining the material proportion of each hot bin, enabling the aggregate synthetic mix to be close to a target mix proportion synthetic mix curve, repeatedly adjusting the feeding proportion of a cold bin to achieve feed balance, then according to the optimal hot asphalt use amount determined by the target mix proportion, changing the hot asphalt use amount up and down at 0.3% mix interval, determining three hot asphalt use amounts, carrying out Marshall test, and determining the optimal oilstone ratio of the production mix proportion.
Further, in the production mix ratio verification, the production mix ratio was used for trial mixing, and the mixed hot asphalt mixture was subjected to marshall test inspection, thereby determining the standard mix ratio for production.
Compared with the prior art, the lignin fiber has higher oil absorption rate, can adsorb and stabilize asphalt, is added into an asphalt mixture to play a role in adsorption stabilization, and can improve the durability of asphalt concrete; and the adsorption and stabilization effects of the lignin fibers can also prevent the mixed asphalt mixture from being separated in the transportation process, so that the uniformity of the asphalt mixture is ensured. The polyester fiber has high toughness, high tensile strength and high elongation at break, and is added into the asphalt mixture to play a role of reinforcing ribs, so that the asphalt concrete bears large tensile deformation under the action of expansion with heat and contraction with cold generated by temperature difference between day and night and external force impact, and the low-temperature crack resistance of the asphalt concrete can be obviously improved. The polymer composite additive can improve the viscosity of asphalt, thereby improving the high-temperature performance of asphalt concrete and enhancing the high-temperature track resistance of an asphalt concrete pavement.
Drawings
FIG. 1 is a flow chart of the method of the present invention.
FIG. 2 is a drawing of an interwoven composite fiber according to the present invention.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and examples.
The technical scheme adopted by the invention is that the interweaved modified asphalt concrete comprises interweaved composite fibers and asphalt concrete; the interweaved composite fiber accounts for 0.2-0.5% of the total mass of the asphalt mixture (namely the total mass of the interweaved composite fiber and the asphalt concrete); the interwoven composite fiber comprises lignin fiber, polyester fiber and polymer composite additive; lignin fiber: polyester fiber: the polymer composite additive comprises the following components in percentage by mass 2; the lignin fiber, the polyester fiber and the polymer composite additive are compounded and blended to form interwoven composite fibers, and the interwoven composite fibers are blended in the asphalt concrete to play a role in comprehensively improving the performance of the asphalt concrete pavement. FIG. 2 is a drawing of an interwoven composite fiber according to the invention.
FIG. 1 is a flow chart of the method of the present invention, an interlaced modified asphalt concrete and surface layer construction method, preparing a lower bearing layer and a construction loft; before the construction of the upper surface layer of the interwoven composite fiber modified asphalt mixture, an SBS modified asphalt adhesive layer is sprayed by an asphalt spraying vehicle and stone chips are synchronously sprayed, the upper surface layer of the interwoven composite fiber modified asphalt mixture is paved after the sprayed adhesive layer is checked to be qualified, and the paved adhesive layer is cleaned in time.
Before construction, the positions of two side piles on the upper layer are released by a total station to control a construction side line, the paving thickness is automatically controlled by a suspension type balance beam automatic control system, and random detection is manually carried out.
In the mixing of the interwoven modified asphalt mixture, the interwoven composite fibers are added by adopting dry mixing and a process for the mixing of the interwoven modified asphalt mixture, and the key points in the mixing are the feeding of additives, the mixing time and the mixing temperature.
The interweaved composite fiber is added by a dry method, and the externally-doped interweaved composite fiber is directly doped into the matrix asphalt mixture by a dry method process without being mixed with asphalt in advance to prepare the interweaved composite fiber modified asphalt.
Avoiding the segregation of the asphalt mixture. The raw materials of the interwoven composite fiber comprise lignin fiber which has high adsorbability and can adsorb stable asphalt, so that the separation of the mixed asphalt mixture in the transportation process is avoided, and the uniformity of the hot-mixed asphalt mixture can be well maintained.
Comprehensively improves the high-temperature stability and the low-temperature crack resistance of the asphalt concrete. The interwoven composite fiber contains polyester fiber and polymer composite additive, the polyester fiber can effectively improve the low-temperature cracking resistance of asphalt concrete, the polymer composite additive can obviously improve the high-temperature rutting resistance of the asphalt concrete, and the comprehensive modification effect of the interwoven composite fiber is obvious.
The road performance is improved, and the construction cost can be obviously reduced. After the interwoven composite fibers are doped into the matrix asphalt mixture, the pavement performance of the composite fibers can reach the level of the SBS modified asphalt mixture, but the composite fibers are lower in cost than the SBS modified asphalt mixture, so that the construction cost can be effectively reduced.
The social benefit is remarkable. The service performance and the service life of the asphalt concrete pavement can be obviously improved, and the generation of early diseases of the asphalt pavement is reduced.
The interweaved composite fiber is put in the hot material bin of the asphalt mixing plant by workers, and before the mixing plant starts to run, the quality of the interweaved composite fiber actually added in each batch of the mixture is accurately weighed according to the quantity of the mixed mixture in each batch. According to the blending amount of the interwoven composite fibers being 0.3 percent of the total mass of the asphalt mixture, the interwoven composite fibers with accurate mass are put into a mixing pot every time. After the mixing plant is opened, when the aggregate is mixed and stirred in a dry mode, weighed interwoven composite fibers are put into the mixing plant from a hot material bin observation port, and the bin door of the hot material bin observation port is closed after the weighed interwoven composite fibers are put into the mixing plant before wet mixing is started, so that the interwoven composite fibers are fully stirred and dispersed, asphalt and the interwoven composite fibers are prevented from overflowing from the hot material bin observation port to cause loss, and the interwoven composite fibers are prevented from being agglomerated with the asphalt without being stirred uniformly to influence the uniformity of asphalt mixture.
The mixing of the interweaved modified asphalt mixture ensures that the adding of the interweaved composite fibers is synchronous with the injecting process of the hot aggregate in the weighing bin, ensures that the dispersivity of the additive is uniformly mixed with the aggregate, and properly prolongs the dry mixing time and the wet mixing time generally. The duration of the mixing time will depend on the configuration and mode of the batch unit used, and the type and amount of interlaced composite fibers incorporated into the mix. In general, the dry mixing time is prolonged by 5 to 15 seconds compared with the ordinary condition, and the wet mixing time is properly prolonged by 5 to 10 seconds compared with the mixing time required by the common asphalt mixture. The total mixing time (dry mixing and wet mixing) of the interwoven modified asphalt mixture is not less than 60s (the specific mixing time is determined by trial mixing), so that the uniform mixing of the asphalt mixture is ensured, and white materials are avoided.
The transport conditions of the mixed and interwoven composite fiber asphalt mixture are basically the same as the transport conditions of the common modified asphalt mixture. Because the raw materials of the interwoven composite fiber comprise the lignin fiber which can better adsorb stable asphalt, the separation of the mixed asphalt mixture in the transportation process can be avoided, and the uniformity of the hot-mixed asphalt mixture can be better kept. The transportation vehicle must also be equipped with coverings such as cotton quilts or waterproof tarpaulins, and the coverings can be used for fully covering the asphalt mixture in the transportation process of the asphalt mixture so as to prevent the asphalt from being oxidized due to the influence of sunlight and air at high temperature and prevent the asphalt mixture from generating temperature segregation. In addition, special attention should be paid to the connection between the paver and the material conveying vehicle, so that the material breaking condition is avoided in the paving process, and the uniform operation of the paver is ensured. The asphalt mixture transported to the construction site is also tested to determine whether its temperature meets the relevant requirements.
Examples
(1) When the paver starts to pave, a certain number of material transporting vehicles are required in front of the paver to ensure continuous paving, and a specially-assigned person commands the material transporting vehicles to slowly back up so that the rear wheels of the vehicles slightly lean against the edges of the hopper of the paver and cannot impact the paver. The material transporting vehicle should be in neutral gear in the unloading process of the spreading machine and is pushed to advance by the power of the spreading machine so as to ensure the flatness of the spreading layer. After the paver is started, whether the loose paving thickness of the mixture meets the requirement or not is detected immediately, paving is continued if the loose paving thickness of the mixture is qualified, otherwise, adjustment is carried out, and the design requirement is met as soon as possible.
(2) Two spreading machines are adopted to carry out full-width spreading in an echelon mode, the distance between the front portion and the rear portion of the two spreading machines is 2-4 m, and the heating temperature of a screed plate of the spreading machine before spreading is above 100 ℃. When in paving, the walking speed of the paver is controlled to be 2-3 m/min. In the process of paving, the paving speed is kept unchanged, the materials are paved slowly, uniformly and continuously without interruption, and the speed cannot be changed randomly or stopped midway, so that the flatness is improved and the segregation of the mixed materials is reduced.
(3) When spreading, the material is vibrated by a self-propelled machine with large amplitude. In order to avoid stopping the paver and waiting for the material, at least 1-2 material-conveying vehicles to be unloaded are arranged in front of the paver, and 1/3 of the mixture is also stored in the hopper, so that the segregation phenomenon generated during paving is avoided.
(4) When the curve road section is paved, the paver is required to advance at a constant speed, the middle part of the curve road section cannot be stopped, the walking direction of the paver is adjusted in time, the paving quality of the curve road section is ensured, and the temperature of the mixture is detected at any time to control the rolling temperature.
(5) For special road sections such as narrow and widened road surfaces and small-scale projects, manual paving can be carried out, a shovel needs to be buckled and paved during paving, a shovel cannot be lifted and thrown, paving and leveling are carried out while force is applied, the shovel and other tools for spreading materials need to be heated for use, paving is carried out continuously, and intermediate pause is avoided; the paved asphalt mixture is rolled.
(6) In the whole paving process, the paving temperature is well controlled, and the requirement on the paving temperature is high due to the high viscosity of the asphalt mixture after the interweaving composite fiber is blended, and the paving temperature is not lower than 130 ℃.
Preferably, in the paving operation process of the asphalt mixture, the paving width, the paving flatness, the paving temperature and the matching between the paving width, the paving flatness, the paving temperature and a material conveying vehicle are controlled emphatically, so that the defects of small waves, segregation, scratches, poor flatness and the like are avoided to the maximum extent, and the paving quality of the road surface is improved.
Preferably, in the rolling of the interwoven modified asphalt mixture, the final flatness and compactness of the asphalt pavement are realized by rolling of a road roller, and as the interwoven composite fibers are added into the asphalt mixture, the rolling quality directly influences the quality of the asphalt pavement, so that the rolling process plays a decisive role in the flatness and compactness. The rolling is carried out according to three stages of initial pressing, secondary pressing and final pressing.
(1) Initial pressure
And (3) carrying out static pressure once by adopting a 12t double-steel-wheel road roller at a higher temperature. When rolling, the driving wheel faces the paver, the road roller rolls from the outside to the center and from the low position to the high position, the adjacent rolling belts are overlapped by 1/3-1/2 of the wheel width, the rolling belts are in a ladder shape and are staggered by 20-30 cm in length, and the whole paving surface is compacted once. The running speed of the road roller should be controlled within 2-3 km/h.
After the initial pressing, the flatness and the road arch should be checked in time, and if necessary, the correction is carried out, if the stacking occurs during the rolling, the rolling can be carried out after manual treatment; if the cross striations occur, the reason needs to be checked and corrective measures need to be taken in time.
(2) Composite press
And (4) carrying out secondary pressing following the initial pressing, and rolling for 4-5 times by adopting four 12t double-steel-wheel vibratory rollers. When the vibratory roller backs a car, the vibratory roller should stop firstly and then stop so as to avoid the formation of bulges. The walking speed of the road roller is preferably controlled to be 3-4.5 km/h.
(3) Final pressure
And final pressing is carried out after re-pressing, and the light receiving surface is subjected to static pressure driving by adopting a 12t double-steel-wheel road roller. Static pressure of the vibratory roller is utilized to ensure that the road surface has no wheel tracks. The walking speed is preferably controlled to be 3-6 km/h.
In the rolling process, the viscosity of the asphalt mixture is high after the interweaving composite fibers are mixed, so that the road roller must be rolled by following a paver to ensure that the mixture is compacted at a high temperature and ensure the compaction quality. The rolling temperature in the initial pressing is not lower than 130 ℃, the re-pressing temperature is not lower than 120 ℃, and the rolling finishing temperature is not lower than 110 ℃. After compaction, traffic can be opened only when the temperature of the pavement is reduced to below 50 ℃.
In addition, the roller is ensured to be wet in the rolling process so as to avoid adhering asphalt mixture, and a mist water spraying method is adopted to prevent the excessive water consumption so as to avoid cooling the surface of the mixture. The road roller can not turn around, move left and right or brake emergently on a newly paved road surface, and can not park all construction equipment on an uncooled mixture surface layer so as to avoid deformation and scatter impurities such as mineral aggregate, oil and the like, and the road roller can open traffic after the compacted asphalt surface layer is completely cooled.
In the seam treatment, the compaction of the longitudinal seam:
the formation of the longitudinal joint is related to the paving process. The longitudinal joint is formed in different conditions and the rolling method is different.
(1) When more than two spreading machines are spread in a echelon in full width, because the temperature of the asphalt mixture of adjacent spreading belts is close, no obvious boundary exists at the longitudinal joint after rolling, and the effect is better after the longitudinal joint is rolled. Two spreading machines are adopted to continuously spread at a distance of 2-4 m from front to back, the spreading thickness of the forward spreading machine is the spreading reference surface of the background spreading machine, and the rolling is integrally and uniformly carried out.
(2) And paving by using a paver, and then returning to the adjacent lanes for paving. The inner side of the paving belt formed by the paving operation method has no lateral limit, the asphalt mixture is easy to generate lateral slippage under the extrusion of the rolling wheel, at the moment, the road roller is pre-pressed once along a longitudinal joint line from a position 30-50 cm away from the inner side edge, then turns around to start initial pressing at the outer side kerb or shoulder, moves 10-15 cm laterally every time of compaction when the road roller is rolled to the range of 30-50 cm, and sequentially presses the inner side to a position 5-10 cm away from the inner side edge. After the adjacent paving belts are paved, rolling the original inner sides of the rolled paving belts in sequence by staggered wheels until the positions of 50-80 cm beyond the longitudinal seam line.
According to the longitudinal joint rolling method, the temperature difference between adjacent paving belts is not too large, the front and rear paving time is not too long, and the time interval is flexibly grasped and controlled according to the climate and temperature conditions.
Compacting of the transverse seam: after the front operation section is paved, the transverse joint is treated technically before the rear operation section is paved. And after the paving of the front operation section is finished, flatness measurement is carried out on the grinding surface near the transverse joint, the vertical joint is cut by a cutting machine, and the part of which the flatness does not meet the standard requirement is removed. Before the construction of the post-operation section, the vertical seam is sprayed with adhesive layer asphalt, and the screed can be continuously paved when the heating temperature is above 10 ℃. And (2) selecting a double-steel-wheel road roller to perform transverse rolling along the transverse joint direction, when the rolling is started, mostly pressing the rolling wheel on a compacted road section, only leaving a wheel width of about 15cm to press on a newly paved mixture, and then, laterally moving the roller to the newly paved road section in sequence by the road roller, wherein the lateral moving amount is 15-20 cm each time until the roller completely crosses the transverse joint.
Health preserving and traffic control: after the complete natural cooling of the paved layer of the interwoven composite fiber modified asphalt mixture pavement, the traffic can be opened when the surface temperature of the mixture is lower than 50 ℃. After the asphalt mixture is rolled and formed, the compaction degree and the compaction thickness of the asphalt surface layer are checked according to the standard requirements.
Claims (7)
1. The interweaved modified asphalt concrete is characterized in that: comprises interweaved composite fiber and asphalt concrete; the interweaved composite fiber accounts for 0.2 to 0.5 percent of the total mass of the asphalt mixture, namely the total mass of the interweaved composite fiber and the asphalt concrete; the interweaving composite fiber comprises lignin fiber, polyester fiber and polymer composite additive; lignin fiber: polyester fiber: the polymer composite additive comprises the following components in percentage by mass 2; the lignin fiber, the polyester fiber and the polymer composite additive are compounded and blended to form interwoven composite fibers, and the interwoven composite fibers are blended in the asphalt concrete to play a role in comprehensively improving the performance of the asphalt concrete pavement.
2. The interlaced modified asphalt concrete according to claim 1, wherein: the asphalt concrete comprises hot asphalt and aggregates, and the aggregates are divided into coarse aggregates and fine aggregates; before adding the interwoven composite fibers into hot asphalt, dry-mixing the interwoven composite fibers with aggregate; in the dry mixing process, polyester fibers and lignin fibers in the interwoven composite fibers are scattered by the aggregates and uniformly dispersed into the coarse aggregates and the fine aggregates, and the polymer composite additive generates plastic deformation under the coupling action of a stress field and a temperature field, one part of the polymer composite additive is adhered to the aggregates, and the other part of the polymer composite additive is broken and dispersed; after the hot asphalt is added, the lignin fibers dispersed in the aggregate adsorb the stable asphalt, the polyester fibers play a role in increasing viscosity and resisting cracking, and the polymer composite additive particles are swelled.
3. The interlaced modified asphalt concrete according to claim 1, wherein: in the mix proportion design of the interwoven modified asphalt mixture, the mix proportion design of the interwoven modified asphalt mixture comprises a target mix proportion design stage, a production mix proportion design stage and a production mix proportion verification stage; in the target mixing proportion design stage, the mixing amount of the interwoven composite fibers is 0.2-0.5% of the total mass of the asphalt mixture; in the design stage of production mix proportion, the mixing mode of the interwoven composite fibers adopts dry mixing, firstly, the interwoven composite fibers and the aggregates are mixed for 60s in a dry mode, so that the interwoven composite fibers are uniformly dispersed in the coarse aggregates, and then, hot asphalt is added and mixed for 60s; the fine aggregate comprises mineral powder, and the mineral powder is added and mixed for 60s; the total mixing time of dry mixing is 3min; in the production mixing proportion verification stage, the aggregate gradation and the hot asphalt dosage in the interwoven modified asphalt concrete are determined by the mixing proportion design.
4. The interlaced modified asphalt concrete according to claim 3, wherein: the dry mixing temperature in the test process is controlled as follows, the heating temperature of the coarse aggregate in the test step of the mix proportion design process is set to be 180-190 ℃, the heating temperature of the hot asphalt in the test step of the mix proportion design process is set to be 150-160 ℃, and the mixing temperature of the asphalt mixture in the test step of the mix proportion design process is 165-175 ℃; the temperature of the mixed asphalt mixture in the test step of the mix proportion design process is 160-170 ℃, and the compaction temperature of the mixed test piece in the test step of the mix proportion design process is 165 ℃.
5. The interlaced modified asphalt concrete according to claim 3, wherein: in the target mix proportion design stage:
1) Selecting target coarse aggregate grading;
selecting a target coarse aggregate gradation according to the mixture type determined by the pavement design;
2) Calculating the ratio of various coarse aggregates to fine aggregates;
carrying out a screening test on the coarse aggregate and the fine aggregate, measuring the relative mineral aggregate density of various coarse aggregates and fine aggregates and the particle composition of various mineral aggregates, and determining the proportion of various coarse aggregates and fine aggregates when the requirements of a grading curve are met;
3) Determining the optimal hot asphalt dosage;
determining the optimal hot asphalt dosage of the interweaved modified asphalt mixture by adopting a Marshall test method; preparing Marshall test pieces by taking the preliminarily drawn target hot asphalt dosage as a median and changing the hot asphalt dosage up and down at the ratio interval of 0.5 percent, wherein the number of the Marshall test pieces is not less than 5; measuring the stability, the flow value and the density of a Marshall test piece by using a Marshall tester at the test temperature and within the test time, and calculating the void ratio, the asphalt saturation and the aggregate clearance ratio; respectively drawing relation curves of the hot asphalt consumption, the density, the stability, the flow value, the void ratio, the hot asphalt saturation and the mineral aggregate void ratio according to the test results and the calculation results, determining the optimal hot asphalt consumption according to the relation curves by a Marshall test method, adjusting the gradation if the optimal hot asphalt consumption cannot meet the requirements, carrying out the batch design again, and carrying out the Marshall test until all indexes can meet the requirements.
6. The interlaced modified asphalt concrete according to claim 3, wherein: in the production mix proportion design stage, according to the proportion of various aggregates determined by a target mix proportion, sampling materials entering each hot storage bin after secondary screening by a mixer, screening, determining the material proportion of each hot storage bin, enabling aggregate synthetic gradation to approach a target mix proportion synthetic gradation curve, repeatedly adjusting the feeding proportion of a cold storage bin to achieve feed balance, then according to the optimal hot asphalt dosage determined by the target mix proportion, changing the hot asphalt dosage up and down at a ratio interval of 0.3%, determining three hot asphalt dosages, performing Marshall test, and determining the optimal oilstone ratio of the production mix proportion.
7. The interlaced modified asphalt concrete according to claim 3, wherein: in the production mix proportion verification, the production mix proportion is used for trial mixing, and the mixed hot asphalt mixture is subjected to a marshall test, thereby determining the standard mix proportion for production.
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