A design method and construction method of a new type of cast asphalt mixture

Abstract

The application relates to the field of buildings, and discloses a design method and a construction method of a novel cast asphalt mixture. A mixture is designed, the mass m2 of asphalt and the mass m3 of filler are obtained, and the designed mixture is optimized through surface texture coefficient design of the novel cast asphalt mixture UHCA or filling degree design of the novel cast asphalt mixture UHCA based on the requirement of a use scene. The surface texture coefficient design of the novel cast asphalt mixture UHCA is designed through the method of adjusting the mixing proportion based on the target requirement of surface texture, the characteristics of UHCA and the volume method. The filling degree design of the novel cast asphalt mixture UHCA is a material design method based on the skeleton void volume filling of UHCA, and the cast mixture of the "upper permeability and lower density" layered type is designed in combination with the material characteristics and the use requirement.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of construction, in particular to a design method and construction method of a new type of cast asphalt mixture. BACKGROUND

[0002] At present, the existing cast asphalt mixture at home and abroad refers to a mixture with high asphalt content and high mineral powder content, and a void ratio less than 1%, which is formed by high-temperature mixing at about 240℃, paving without rolling, and relying on the flowability of the mixture itself. The binder of the cast asphalt mixture includes ordinary asphalt or modified asphalt, Trinidad Lake Asphalt TLA, or a mixture of the two (generally TLA 25-30%), fine aggregate (<2mm) is generally limestone, and coarse aggregate is usually basalt stone. It mainly includes German Guss Asphalt (GA) and British Mastic Asphalt (MA) cast asphalt mixture. In terms of material design, the mineral powder content is as high as 22%, which belongs to a suspended dense structure. At the same time, due to the high asphalt content, low-grade hard lake asphalt (usually Trinidad Lake Asphalt) must be added. According to the Technical Specification for Design and Construction of Highway Steel Bridge Deck Pavement (JTG / T3364-02—2019) of China, the current rutting dynamic stability technical requirement of cast asphalt pavement material is 300-800 times / mm.

[0003] The existing cast asphalt mixture is a kind of asphalt concrete which is directly paved without rolling after high-temperature mixing, and has the characteristics of high asphalt content and high mineral powder content, so it has excellent performance in terms of fatigue resistance, durability, deformation compliance, and bonding performance. The cast construction does not need rolling, which effectively avoids the problem of local insufficient compaction of ordinary asphalt mixture, and the mixture inside has no void after construction, and the integrity is good. In view of the advantages of cast asphalt mixture, it is usually used for bridge deck pavement.

[0004] The current cast mixture contains a large amount of fine aggregate. After the mortar composed of fine aggregate and cement paste is mixed with aggregate, the flowability of the mixture is large, and the components are uniformly mixed and not easy to separate. After cast construction, the whole is dense, and the void ratio is less than 1%. Due to the large amount of cement paste, the surface after construction is smooth, and there is basically no structural depth. Therefore, it is necessary to sprinkle 0.4-0.6% of pre-mixed asphalt stone with a particle size of 10-15mm on the surface of the cast asphalt layer just after paving, and press it into the surface with a light roller while hot, so as to form a rough anti-skid surface with a large surface structure after cooling. However, such a process is prone to particle loss and loss of surface structure, and cannot be restored, resulting in loss of surface function. In addition, the traditional cast asphalt mixture forms a dense mixture with almost no voids after cast construction, and cannot realize layered paving. For some road sections with special requirements such as drainage and noise reduction, it cannot meet the functional requirements of the road section.

[0005] The new type of cast asphalt mixture UHCA refers to a high asphalt content and a void ratio less than 1% of macadam mixture formed by mixing at a high temperature of 200-240 degrees Celsius and relying on the flowability of the mixture itself or the slurry assisted by vibration. Compared with the conventional dense graded asphalt mixture commonly used at present, the new type of cast asphalt mixture UHCA has a high asphalt content, a smaller void ratio, a stronger tensile deformation capacity, better durability, and good high-temperature stability; the asphalt content can be flexibly adjusted to facilitate the design of functional pavement materials with different performance; the high-temperature casting process is adopted to eliminate the need for rolling, which is suitable for the construction of sites with limited operation surface; and the new type of cast asphalt mixture UHCA has better waterproof, fatigue-resistant, anti-aging, and follow-up and bonding properties.

[0006] Therefore, a material design method and a construction method of a new type of cast asphalt mixture are provided. SUMMARY

[0007] (1) Technical problems to be solved

[0008] In view of the deficiencies of the prior art, the present application provides a material design method and a construction method of a new type of cast asphalt mixture. Based on the material design method of UHCA skeleton void volume filling, the new type of cast asphalt mixture UHCA has a high construction temperature and good flowability, the slurry automatically sinks to fill the lower void after casting construction, the coarse aggregate macadam on the upper part is exposed, a good integrated rough surface structure can be formed, and the surface structure needs to be optimized in terms of the maximum particle size, material usage, structure depth, etc. to meet different surface function requirements. The UHCA mixture has the characteristics of large slurry flowability and automatic slurry sinking during casting construction, so the slurry filling degree index is proposed to control the design slurry usage, so as to design the new type of cast asphalt mixture UHCA pavement with open grading on the upper part and dense on the lower part.

[0009] (2) Technical solutions

[0010] To achieve the above-mentioned purposes, the present application provides the following technical solutions: a design method of a new type of cast asphalt mixture, characterized in that it comprises the following steps:

[0011] Step 1: design the mixture to obtain the mass m2 of asphalt and the mass m3 of filler;

[0012] Second step: based on the need of using scene, the mixture designed above is optimized by the surface texture coefficient design of new type cast asphalt mixture UHCA or the filling degree design of new type cast asphalt mixture UHCA.

[0013] Preferably, the surface texture coefficient design of new type cast asphalt mixture UHCA includes the following contents:

[0014] S1: assuming that the surface of UHCA needs uneven surface texture, wherein the area of the concave region is 1 / m of the total surface area of the test piece, and the surface texture depth is 1 / n of the maximum particle size, then the volume v3 deducted by the surface texture is calculated according to the following formula:

[0015]

[0016] In the formula, d is the maximum particle size of the mixture, a and b are the length and width of the test piece or the pavement structure layer to be cast respectively, and m and n are both constants of the surface texture design.

[0017] S2: the coarse aggregate mass m1 is substituted into the coarse aggregate void volume v1 to obtain the total volume of the mortar to be filled, that is, the coarse aggregate void volume:

[0018]

[0019] In the formula, ρ SC is the bulk density of the coarse aggregate in the tamped state, VCA DRC is the void ratio of the coarse aggregate in the tamped state, V v is the design void ratio, and a, b, and h are the length, width, and thickness of the test piece or the pavement structure layer to be cast.

[0020] S3: the ratio k1 of the volume v3 deducted by the surface texture to the total volume v1 of the mortar to be filled is calculated according to the following formula:

[0021]

[0022] S4: the surface texture coefficient S c of the new type cast asphalt mixture mortar design considering the surface texture is calculated according to the following formula:

[0023]

[0024] S5: the new type cast mixture UHCA pavement structure with surface texture is obtained by reducing the design asphalt quality and the design filler quality according to the surface texture coefficient.

[0025] Preferably, the specific contents of the filling degree design of the new type cast asphalt mixture UHCA are as follows:

[0026] S1: define the filling degree Fd as the filling degree of the mortar in the mixture to the coarse skeleton gap, i.e. the ratio of the thickness of the dense part of the mixture to the total thickness of the mixture, Fd ranges from 0 to 1.

[0027] S2: control the amount of mortar by filling degree design to realize the layered design of the mixture, the actual asphalt amount and the actual filler amount considering the filling degree are equal to the design asphalt amount and the design filler amount multiplied by the filling degree, specifically as follows:

[0028]

[0029]

[0030] In the formula, The actual asphalt amount and the actual filler amount considering the filling degree are obtained.

[0031] A construction method of a new type of paving asphalt mixture, comprising the following steps:

[0032] First step: prepare the filler, coarse aggregate and asphalt, the heating temperature of the coarse aggregate, filler and asphalt is 230-260℃;

[0033] Second step: mix the asphalt mortar, add the filler and asphalt into the mixer for mixing, the mixing temperature is 220-240℃, and the mixing time is 3-5min;

[0034] Third step: use the Cooker vehicle to mix and transport the new type of paving asphalt mixture;

[0035] Fourth step: use the paver with a vibrating beam to pave the new type of paving asphalt mixture, the paving thickness is 2-10cm, and the paving temperature should not be lower than 200℃;

[0036] Fifth step: when the temperature of the new type of paving asphalt mixture decreases to about 130-160℃, use a small tonnage steel wheel roller to roll single time to flatten the coarse aggregate particles on the surface of the UHCA mixture, and form a hot rolling flat surface.

[0037] Preferably, in the third step, the mixture is kept at 220-240℃ during transportation, the Cooker should start the stirring function before adding the asphalt mortar, hot coarse aggregate should be added within 10min after adding the mortar, the coarse aggregate should be transported to the construction site immediately after being added, the stirring should be continued during transportation, the coarse aggregate should be mixed in the Cooker with asphalt mortar for 3min before paving, and the total mixing time after adding the coarse aggregate to before paving should not exceed 1h.

[0038] The application of a new type of paving asphalt mixture is used for bridge deck pavement, tunnel pavement, pavement structure layer, surface wearing layer, crack repair and pothole repair, etc.

[0039] (III) Beneficial Effects

[0040] Compared with the prior art, the application provides a design method and a construction method of a new type of paving asphalt mixture, which has the following beneficial effects:

[0041] 1. The design method and the construction method of the new type of paving asphalt mixture, the high-temperature stability of the mixture is obviously better than that of ordinary paving asphalt mixture, the anti-rutting capacity is excellent, the coordinated deformation capacity is strong, and the durability is good. Meanwhile, the problems of insufficient durability of ordinary asphalt mixture and poor high-temperature stability of paving asphalt mixture are solved.

[0042] 2. The design method and the construction method of the new type of paving asphalt mixture can accurately and efficiently design surface structures of different depths from the perspective of material design, and do not affect the road performance of the mixture, and can meet the diversified needs of the road surface function.

[0043] 3. The design method and the construction method of the new type of paving asphalt mixture, the new type of paving mixture has excellent fluidity, even if large-thickness paving, the new type of paving mixture can be self-compacted and formed into a skeleton structure without rolling, which simplifies the construction process, improves the construction quality and efficiency. Through the filling degree design, a large-thickness "upper transparent lower dense" layered pavement structure can be paved at one time, which can meet the functional needs of the multi-layer pavement structure and avoid the problem of low efficiency of layered construction, and the application scenarios are wide. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 It is a schematic diagram of surface structure effect;

[0045] Figure 2 It is a schematic diagram of the concept of upper transparent lower dense UHCA mixture;

[0046] Figure 3 It is a schematic diagram of the implementation effect of the upper transparent lower dense UHCA mixture. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0048] A design method of a new type of paving asphalt mixture, comprising the following steps:

[0049] The fine aggregate of 2.36 mm or 4.75 mm or above is exempted from grading, and the coarse aggregate forms a skeleton structure, and the asphalt mortar fills in the voids of the skeleton structure. The high-temperature stability of the mixture is improved by the skeleton effect of the coarse aggregate and the binding effect of the mortar, and the dynamic stability of the rut of the new paving asphalt mixture can reach more than 3000 times / mm. At the same time, the deformation coordination, fatigue resistance and binding performance of the mortar can be fully utilized, and the durability of the mixture is significantly improved.

[0050] (1) The fine aggregate of 2.36 mm or 4.75 mm or above is exempted from grading, and the coarse aggregate can have one, two or more grades, and the grading is designed according to the principle of maximum compaction.

[0051] (2) The powder-mortar ratio of the asphalt mortar is 0.6-1.5.

[0052] (3) The asphalt is high-viscosity modified asphalt.

[0053] (4) The mixture ratio of the new paving asphalt mixture is designed based on the volume method, and the steps are as follows:

[0054] S11. If the length, width and thickness of the test piece or the pavement structure layer to be paved are a, b and h respectively, the required coarse aggregate mass m1 is obtained according to formula 1:

[0055] m1=a×b×h×p SC (1)

[0056] In the formula, p SC is the bulk density of the coarse aggregate in the tamped state, which is determined according to the specification JTG E42-2005.

[0057] S12. The void volume of the coarse aggregate is v1, which is calculated according to formula 2:

[0058]

[0059] In the formula, VCA DRC is the air voids of the coarse aggregate in the tamped state, which is determined according to the specification JTG E42-2005, and V v is the design air voids.

[0060] S13. The volume v2 of the asphalt and filler, i.e. the asphalt mortar, is calculated according to formula 3:

[0061]

[0062] In the formula, p a is the density of the asphalt, p P is the density of the filler, m2 is the mass of the asphalt, and r is the powder-mortar ratio.

[0063] S14. The asphalt mortar fills in the coarse aggregate skeleton voids, and the mortar volume is equal to the volume of the coarse aggregate skeleton voids, i.e. v1=v2, combined with formula 2 and formula 3, the asphalt mass m2 and the mass of the filler m3 are calculated according to formula 4 and formula 5 respectively:

[0064]

[0065] m3=m2xr (5)

[0066] A surface structure design method of UHCA.

[0067] The application provides a surface structure design method of a new type of paving asphalt mixture UHCA.

[0068] In actual engineering, different road sections have different requirements for surface structure and skid resistance, which is a problem that must be considered in mixture design and construction. The existing GA or MA paving asphalt mixture design considers the performance of the mixture, and cannot control the surface structure of the mixture, so the surface structure of the mixture cannot be designed. Instead, after paving, 0.4-0.6 % of pre-mixed asphalt macadam with a particle size of 10-15 mm is scattered, and a light roller is used to press the asphalt macadam into the surface of the just-paved UHCA layer, so that a rough skid-resistant surface with large surface structure is formed after cooling. However, such a process is prone to particle loss and cannot restore the surface structure, and the surface function is easily lost and damaged. The new type of paving asphalt mixture UHCA does not contain fine aggregate, the particle size of the coarse aggregate is large, and the fluidity of the mortar is good, so the mortar can sink and fill in the skeleton voids during construction. Therefore, the surface structure of the mixture can be adjusted by designing the mortar dosage and the skeleton composition, that is, by deducting a certain amount of mortar, the fluidity of the mortar can be used to make the surface of the mixture after construction have a certain structure depth.

[0069] When the mortar design dosage is not enough to completely fill the voids of the main skeleton, because the new type of paving asphalt mixture UHCA has high construction temperature and good fluidity, the mortar can automatically sink and fill the lower voids, and the upper coarse aggregate macadam is exposed, so that a good integrated rough surface structure is formed. Meanwhile, the roughness of the surface structure can be flexibly adjusted by adjusting the composition and the maximum nominal particle size of the coarse aggregate. If the mixture is required to have a certain surface structure to meet the requirements of road skid resistance and other functions, the volume of the surface structure should be deducted from the volume of the mortar to be filled. In order to facilitate operation, the application provides a surface structure coefficient S c for the mortar dosage design of the new type of paving asphalt mixture UHCA considering the surface structure.

[0070] S1. Assuming that the UHCA test piece has uneven surface structure, wherein the area of the concave region is 1 / m of the total surface area of the test piece, and the surface structure depth is 1 / n of the maximum particle size (m and n are constants set according to the required surface structure), the volume v3 of the surface structure to be deducted is calculated according to formula 6:

[0071]

[0072] S2. According to formula 1 and formula 2, the total volume v1 of the mortar to be filled is obtained, as shown in formula 7:

[0073]

[0074] S3. Then, the volume ratio k1 of the volume of the surface structure to be deducted and the total volume of the mortar to be filled is calculated according to formula 8:

[0075]

[0076] S4. Then, the surface structure coefficient S of the new type of cast asphalt mixture mortar amount design considering the surface structure is calculated according to formula 9: c

[0077]

[0078] S c Physical meaning of the surface structure coefficient: the surface structure coefficient is related to the set surface structure depth, surface structure area, thickness of the test piece or pavement structure layer, maximum particle size of coarse aggregate, and void ratio of the coarse aggregate in the tamping state.

[0079] If the mixture surface needs to have a certain surface structure, the amount of asphalt and filler can be reduced according to the surface structure coefficient provided by the present application during the surface structure design, so as to obtain the new type of cast mixture UHCA pavement structure with surface structure.

[0080] Design of the filling degree of UHCA.

[0081] The present application provides a filling degree design method of the new type of cast asphalt mixture UHCA.

[0082] ​The new type of cast-in-place UHCA (Ultra-High Hybrid Carbonate) mix utilizes a cast-in-place process for self-compacting, with vibration-assisted compaction possible when necessary. It allows for one-time paving of large thicknesses. Due to the good fluidity of the binder slurry, it compacts from bottom to top within the mix, theoretically resulting in zero internal porosity, but in practice, it is typically below 1%. If the binder slurry dosage is too high, an overfilled UHCA pavement will form, with the surface entirely composed of binder slurry and the lower layer a dense skeleton, completely losing its structural depth. If the binder slurry dosage is appropriately reduced, a UHCA pavement with a certain surface texture and a dense lower layer will be formed. If the binder slurry dosage is even lower, a UHCA pavement with a dense lower layer and an open-graded upper layer will be formed. When used as a surface layer requiring drainage, the fill degree can be designed to create a "permeable top, dense bottom" layered structure, where the lower mix has a dense skeleton structure, while the mix within a certain height range on the surface has a porous skeleton structure, meeting surface drainage requirements. A conceptual diagram is attached. Figure 2 To facilitate operation, this invention proposes a novel filling degree F for cast-in-place asphalt mixtures. d And its application methods.

[0083] Fill factor F d F is defined as the degree to which the adhesive fills the voids in the coarse skeleton of the mixture, that is, the ratio of the thickness of the dense part of the mixture to the total thickness of the mixture. d The range is 0 to 1.

[0084] In mixture design, the amount of binder is controlled by the filler design, thereby achieving the layered design of the mixture. Specifically, the actual amount of binder (asphalt and filler) is equal to the amount of binder (asphalt and filler) without considering the filler, multiplied by the filler, as shown in Equations 10 and 11.

[0085]

[0086]

[0087] In the formula, Divided into actual asphalt usage considering filler content and filler usage, F d This refers to fill factor. Typically, F... d ≤1, determined according to surface function requirements.

[0088] A novel construction method for cast-in-place asphalt mixtures includes the following steps:

[0089] S1. Material preparation and heating.

[0090] Prepare filler, coarse aggregate and asphalt. The heating temperature of coarse aggregate, filler and asphalt is 230℃~260℃.

[0091] S2.UHCA asphalt mortar mixing.

[0092] The asphalt mortar is mixed in a mixing station, and the filler and asphalt are added into a mixer for mixing at a mixing temperature of 220-240°C for 3-5 minutes.

[0093] S3. Mixing and transporting of UHCA mixture

[0094] The mixed asphalt mortar is loaded into a Cooker vehicle with temperature control and stirring function, and then the coarse aggregate is added into the Cooker vehicle with the asphalt mortar for mixing. The temperature of the Cooker vehicle is 220-240°C, and the temperature control system should be started in advance for preheating before the asphalt mortar is added. The asphalt mortar is loaded into the Cooker vehicle after the temperature reaches the set temperature.

[0095] The stirring function of the Cooker should be started before the asphalt mortar is added, and the hot coarse aggregate should be added within 10 minutes after the asphalt mortar is added. The coarse aggregate should be transported to the construction site immediately after being added, and the stirring should be continued during the transportation. The coarse aggregate is mixed for 3 minutes in the Cooker with the asphalt mortar, and then paving is performed. The total mixing time after the coarse aggregate is added to the paving should not exceed 1 hour.

[0096] S4. Paving of UHCA mixture

[0097] The paving of the UHCA mixture can use the current paving technology, or can use the hot-mixed asphalt mixture paver. The paving machine with a vibrating beam is used to pave the new type of paving asphalt mixture UHCA, and the paving thickness can be 2-10 cm. The vibrating beam vibrates the surface to make the skeleton structure more compact. The paving temperature should not be lower than 200°C.

[0098] S5. Surface leveling of UHCA

[0099] When the surface temperature of the UHCA mixture decreases to about 130-160°C, a small-tonnage steel wheel roller is used for single-rolling to level the coarse aggregate particles on the surface of the UHCA mixture, and a hot-rolling flat surface is formed to reduce the traffic vibration and noise. For the upper open-graded UHCA with small filling degree, the auxiliary rolling can further compact the skeleton to improve the anti-rutting ability and durability.

[0100] S6. Inspection and adjustment of UHCA surface structure

[0101] The structure of the UHCA pavement surface is inspected to see whether it meets the requirements. If not, the F d parameters and the amount of mortar are adjusted in a timely manner.

[0102] S7. Open traffic

[0103] The traffic is opened after the road surface temperature decreases to the ambient temperature.

[0104] The application of a new type of paving asphalt mixture, the new type of paving asphalt mixture has good fluidity, free-rolling paving construction, and can form a skeleton structure by self-compaction, and the maximum paving thickness can reach 20 cm. The new type of paving asphalt mixture has excellent high-temperature stability, and the dynamic stability of rutting can reach more than 3000 times / mm, and has good deformation coordination performance and fatigue resistance. The new type of paving asphalt mixture has wide application scenarios, and can be used for bridge deck pavement, tunnel pavement, pavement structure layer, surface wear layer, crack repair and pit repair.

[0105] Case one:

[0106] A new type of paving asphalt mixture is designed. The new type of paving asphalt mixture designed by the method of the application is used for repairing after slotting at the crack of the asphalt pavement, and the surface of the new type of paving mixture after slotting and filling is not paved with a cover again, so the surface of the mixture is required to be designed with a certain surface structure.

[0107]

Mixture design

[0108] (1) The skeleton structure is free of fine aggregate below 4.75 mm, and two grades of coarse aggregate of 4.75 mm-9.5 mm and 9.5 mm-13.2 mm are designed for grading, and the grading is designed according to the principle of maximum density, and the mass ratio of the two grades of 4.75 mm-9.5 mm and 9.5 mm-13.2 mm is 62.7:37.3.

[0109] (2) The initial powder-glue ratio is 1.2.

[0110] (3) The asphalt is high-viscosity modified asphalt produced by Dongguan Taihe Asphalt Products Co., Ltd., and the dynamic viscosity at 60 DEG C is greater than 580000 Pa·s, and the density p of the asphalt is 1.03 g / cm a . The crushed stone is diabase produced by Guigang Stone Yard, and the bulk density p of the mixed crushed stone configured according to the design grading is 2.862 g / cm 3 , the packing density p in the rammed state is 1.883 g / cm b , and the calculated gap ratio VCA of the coarse aggregate in the rammed state is 34.2%. 3 Sc 3 DRC The filler is limestone powder produced by Yingde Changfeng Mine Stone Processing Factory, and the density p is 2.823 g / cm P , and the design void ratio is 0. 3

[0111] (4) The mixture ratio of the new type of paving asphalt mixture is designed based on the volume method, and the steps are as follows:

[0112] ​​​​①Preparation of rutting plate test piece, through indoor test design mixture ratio. Rutting plate test piece length, width, thickness are 30cm, 30cm, 5cm, according to formula 1, coarse aggregate amount is calculated, m1=a×b×h×ρ SC = 30×30×5cm×1.883g / cm 3 = 8473g.

[0113] ②According to formula 2, coarse aggregate void volume is calculated,

[0114] ③According to formula 3, asphalt and filler, namely asphalt mortar volume is calculated,

[0115] ④Mortar volume is equal to coarse aggregate skeleton void volume, combined with the above ② and ③, asphalt mass m2, filler mass m3 are obtained respectively:

[0116]

[0117] m3=m2×r=1469g

[0118] In summary, without considering the surface structure, the material amount required for a rutting plate test piece is: coarse aggregate 8473g, of which 4.75-9.5mm crushed stone 5313g, 9.5-13.2mm crushed stone 3160g; asphalt 1049g, mineral powder 1469g.

[0119] (5) Surface structure design

[0120] The material amount obtained by the above calculation is the material amount without setting surface structure, actual application requires that the surface of the mixture designed this time has a certain surface structure, therefore, surface texture coefficient needs to be calculated, and the mortar amount needs to be reduced accordingly.

[0121] ①Assume that the area of the recessed area in the test piece surface structure is 1 / 2 of the total surface area, and the surface structure depth is 1 / 5 (about 2.6mm) of the maximum particle size (13mm), according to formula 11, the mortar amount of the new type of paving asphalt mixture considering surface structure is calculated, surface texture coefficient S c :

[0122]

[0123] Therefore, when the specimen height is 5 cm and the maximum aggregate particle size is 13.2 mm, the surface texture coefficient of the mortar surface structure obtained according to the designed surface structure is 0.9485. At this time, the amount of material required for one rutting plate specimen is: 8473 g of coarse aggregate (5313 g of 4.75-9.5 mm crushed stone and 3160 g of 9.5-13.2 mm crushed stone), 1049 x 0.9485 = 995 g of asphalt, and 1469 x 0.9485 = 1393 g of mineral powder. The amount of asphalt is 9.16%.

[0124]

Mixture preparation and molding

[0125] The mixture preparation adopts a pouring process.

[0126]

Performance test

[0127] (1) Rutting test

[0128] The rutting test results of the new pouring asphalt mixture of Case One are shown in Table 1, and the test temperature is 60°C.

[0129] Table 1: Rutting test results

[0130] Test No. Rut depth (mm) Rut dynamic stability (times / mm) 1 2.2125 3957 2 2.2635 3898 3 2.1287 4021

[0131] As can be seen from the test results, the rutting dynamic stability of the new pouring asphalt mixture is greater than 3800 times / mm, and the high-temperature stability of the mixture is good.

[0132] (2) Surface structure

[0133] The surface structure of the specimen is shown in the attached Figure 1 figure. As can be seen from the figure, the coarse aggregate particles on the surface of the specimen are uniformly distributed, and the surface structure is good. The sand laying method is used to measure the surface texture depth TD b of the specimen, which is 2.21 mm, much larger than the anti-skid technical requirement of the expressway specified in the “Highway Asphalt Pavement Design Specification” (JTG D50-2017). The pendulum friction tester is used to measure the BPN 20 of the surface of the specimen, which is 75.13. This shows that the surface structure and anti-skid performance of the new pouring asphalt mixture obtained through surface structure design are good, and the design goal is achieved.

[0134] Case Two:

[0135] A new pouring asphalt mixture is designed for the upper layer of an expressway. The rainfall of this section is large, and in order to ensure driving safety, the surface needs to have a drainage function, so a 2 cm thick skeleton void type new pouring asphalt mixture is set on the surface.

[0136]

Mixture design

[0137] The same material as in Case 1 is used for design, so steps (1) to (4) are the same as in Example 1.

[0138] (5) Filling degree design.

[0139] The total height of the test piece is 5 cm, the thickness of the surface skeleton gap type mixture is 2 cm, and the thickness of the lower skeleton dense type mixture is 3 cm, so the mortar filling degree F is d = 3 / 5 = 0.6. According to the design results of Example 1, the asphalt content is 1049 g and the mineral powder content is 1469 g when the surface structure is not considered and the filling degree is 1. Therefore, the asphalt content and the mineral powder content are:

[0140]

[0141]

[0142] Therefore, when the test piece height is 5 cm and the maximum aggregate size is 13.2 mm, the total height of the test piece is 5 cm, the filling degree is 0.6, i.e. the lower part of the test piece is 3 cm of skeleton dense type mixture and the upper part is 2 cm of skeleton gap type mixture, the material content required for a rutting test piece is: coarse aggregate 8473 g (of which 4.75-9.5 mm crushed stone 5313 g, 9.5-13.2 mm crushed stone 3160 g), asphalt 629 g, mineral powder 881 g.

[0143]

Performance test

[0144] (1) The permeability coefficient of the mixture is measured by the permeability coefficient test of the drainage asphalt pavement design and construction technical specification (JTG / T 3350-03—2020), and the permeability coefficient of the test piece is 0.31 cm / s, which meets the technical requirements of the drainage asphalt mixture proportioning design (the permeability coefficient is not less than 0.20 cm / s).

[0145] (2) Filling degree test

[0146] The test piece after the water permeation test is cut open to check the filling degree. The test piece section is shown in the accompanying Figure 3 , and the design reference line of the filling degree is drawn. As can be seen from the figure, the mixture above the reference line contains a large number of voids, and the dense type mixture is below the reference line. The boundary between the dense part and the void part is basically consistent with the design reference line and parallel to the surface of the test piece.

[0147] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A design method of a new type of cast asphalt mixture, characterized in that, It comprises the following steps: First step: design the mix to get the mass of asphalt and the mass of filler ; The second step: based on the need of the use scene, the design of the surface structure coefficient of the new type of cast asphalt mixture UHCA or the design of the filling degree of the new type of cast asphalt mixture UHCA is used to optimize the design mixture; The design of the surface structure coefficient of the new type of cast asphalt mixture UHCA comprises the following contents: S1: Assuming that the UHCA surface requires a concave-convex surface structure, wherein the area of the concave region is 1 / m of the total surface area of the test piece, and the surface structure depth is 1 / n of the maximum particle diameter, the volume to be deducted from the surface structure v 3 is calculated according to the following formula: ； In the formula, d is the maximum particle size of the mixture, a and b are the length and width of the cast specimen or the pavement structure layer respectively, and m and n are constants of the surface structure design; S2: the coarse aggregate void volume v1 is obtained by substituting the coarse aggregate mass m1 into the coarse aggregate void volume v1, that is, the total volume of the mortar to be filled: ； wherein p SC is the bulk density of the coarse aggregate in the tamped state, VCA DRC is the air voids of the coarse aggregate in the tamped state, V v is the design air voids, wherein a, b, h are the length, width, and thickness of the test specimen or pavement structure layer of the mixture to be cast. S3: volume subtracted due to surface configuration v 3 and the total volume of the grout to be filled v The ratio k1 of 1 is calculated according to the following formula: ； S4: Surface texture coefficient S for the design of the amount of new type of paving asphalt mixture mortar considering surface texture c The following formula is used for calculation: ； S5: the new type of cast mixture UHCA pavement structure with surface structure is obtained by reducing the design asphalt mass and the design filler mass according to the surface structure coefficient.

2. A method of designing a new cast asphalt mixture as claimed in claim 1, characterized in that: The specific content of the design of the filling degree of the new type of cast asphalt mixture UHCA is as follows: S1: the filling degree Fd is defined as the filling degree of the mortar in the coarse skeleton void of the mixture, that is, the ratio of the thickness of the dense part of the mixture to the total thickness of the mixture, and the range of Fd is 0~1; S2: the amount of mortar is controlled by the design of the filling degree to realize the layered design of the mixture, and the actual asphalt amount and the actual filler amount considering the filling degree are equal to the design asphalt amount and the design filler amount multiplied by the filling degree, which is specifically as follows: ； ； In the formula, , The actual asphalt amount and the actual filler amount considering the filling degree are divided into ρ a is the asphalt density, ρ P is the filler density, and r is the powder-gum ratio.

3. A method for construction of a new cast asphalt mixture, based on the method for design of a new cast asphalt mixture according to any one of claims 1-2, characterized in that, It comprises the following steps: The first step: preparing the filler, coarse aggregate and asphalt, and the heating temperature of the coarse aggregate, filler and asphalt is 230~260 DEG C; The second step: mixing the asphalt mortar, the filler and asphalt are added into the mixer for mixing, the mixing temperature is 220~240 DEG C, and the mixing time is 3~5 min; The third step: using the Cooker vehicle to mix and transport the new type of cast asphalt mixture; The fourth step: using the paving machine with a vibrating beam to pave the new type of cast asphalt mixture, the paving thickness is 2~10 cm, and the paving temperature should not be lower than 200 DEG C; The fifth step: when the temperature of the new type of cast asphalt mixture decreases to about 130~160 DEG C, a small tonnage steel wheel roller is used for single rolling to flatten the coarse aggregate particles on the surface of the UHCA mixture, and a hot rolling flat surface is formed.

4. A method of construction of a novel cast asphalt mix as claimed in claim 3, wherein: In the third step, the mixture is kept at 220~240 DEG C during transportation, the Cooker should start the stirring function before the asphalt mortar is added, the hot coarse aggregate should be added within 10 min after the addition of the mortar, the coarse aggregate should be transported to the construction site immediately after being added, and the stirring should be continued during transportation. The coarse aggregate is added into the Cooker with asphalt mortar and mixed for 3 min before paving, and the total mixing time after the addition of the coarse aggregate should not exceed 1 hour.

5. A method of construction of a novel cast asphalt mix as claimed in claim 3, wherein: The new type of cast asphalt mixture is used for bridge deck pavement, tunnel pavement, pavement structure layer, surface wearing layer, crack repair and pit repair.

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