End splicing method after separated paving of CRC structure on old cement concrete pavement

Abstract

The present invention discloses a construction method for end splicing after separating and paving a CRC structure on an old cement concrete pavement, which includes: Step S1: Determine the pavement length of the transition section and remove the old road slabs in the transition section; determine the pavement length of the transition section according to the elevation difference at the joint between the old road and the newly built pavement and the allowable maximum longitudinal slope; Step S2: By determining the design parameters of each structural layer in the transition section, install formwork in the transition section and arrange steel mesh; Step S3: Construction at the joint between the transition section and the old road; Set a transverse expansion joint with an appropriate width at one end where the transition section is connected to the old road, and set a longitudinal construction joint during separate construction; Step S4: Second-phase construction of the transition section; According to the designed thickness of each structural layer of the pavement in the transition section, pour cement concrete with the corresponding thickness in the formwork, and after curing, pave an asphalt functional layer. The present invention has the advantages of simple principle, easy construction, low cost, short construction period, good environmental protection, etc.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of road engineering, and particularly refers to a construction method for end splicing after a separated CRC structure is overlaid on an old cement concrete pavement. Background Art

[0002] In the field of pavement facilities in modern construction projects, there are a certain number of cement concrete pavements. With the rapid development of the regional economy, the traffic volume is also increasing rapidly, the traffic flow and overweight vehicles are gradually increasing, and the erosion of natural disasters such as rainwater and floods has led to continuous road diseases. The pavement structure of traditional cement concrete pavements has been severely damaged, and the service performance of some sections has seriously declined, thus affecting vehicle driving. Therefore, it is necessary to repair and transform the old cement pavement.

[0003] Through research and analysis of the above-mentioned traditional cement concrete pavements (original old cement concrete pavements), it can be seen that the deflection detection of the original old cement concrete pavement slabs in the vast majority of sections is small, indicating that the overall structure strength of the old road is still acceptable and has utilization value. If the pavement is completely re-laid, it will require a high cost, and the entire construction period is relatively long, and the road closure time is long, which directly affects the traffic smoothness of the surrounding area. Furthermore, there will be a certain environmental impact on the construction site and its surroundings during the entire construction process. Summary of the Invention

[0004] The technical problem to be solved by the present invention lies in: aiming at the technical problems existing in the prior art, the present invention provides a construction method for end splicing after a separated CRC structure is overlaid on an old cement concrete pavement, which has a simple principle, is easy to construct, has a low cost, a short construction period, and good environmental protection.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An end splicing method after a separated CRC structure is overlaid on an old cement concrete pavement, which includes:

[0007] Step S1: Determine the pavement length of the transition section and remove the old road slabs in the transition section; determine the pavement length of the transition section according to the elevation difference between the old road and the newly built pavement joint and the allowable maximum longitudinal slope;

[0008] Step S2: Construction in the first stage of the transition section; by determining the design parameters of each structural layer in the transition section, install formwork in the transition section and arrange the steel mesh; the steel mesh includes transverse steel bars and longitudinal steel bars;

[0009] Step S3: Construction at the connection between the transition section and the old road; set a transverse expansion joint with an appropriate width at one end where the transition section is connected to the old road, and set a longitudinal construction joint when constructing in sections;

[0010] Step S4: Construction of the second stage of the transition section; according to the designed thickness of each structural layer of the road surface in the transition section, pour cement concrete with the corresponding thickness in the formwork, and lay an asphalt functional layer after curing.

[0011] As a further improvement of the method of the present invention: the process of step S1 includes:

[0012] Step S101: Obtain the allowable maximum longitudinal slope value α;

[0013] Step S102: Obtain the shortest length L of the transition section road surface min ; Considering the original longitudinal slope α0 of the old road at the joint and the elevation difference H between the old road and the newly built road surface, calculate the shortest length L of the transition section road surface min :

[0014] α' = α ± α0

[0015] L min = H / α'

[0016] Wherein, when it is an uphill section from the old road to the newly built road surface, take the "-" sign, and when it is a downhill section, take the "+" sign;

[0017] Step S103: Adjust the length L of the old cement road slab in the transition section to be broken and excavated;

[0018] Step S104: After excavating the old slab, tamp and level the base course.

[0019] As a further improvement of the method of the present invention: the following conditions are met in step S103:

[0020] (1) It is required that the length of the old road slab to be excavated is not less than the calculated shortest length L of the transition section road surface min ;

[0021] (2) When there are transverse joints in the old cement road surface, the excavated old cement road slab is appropriately extended, and the edge is taken at the original transverse joint of the old road, so as to excavate the whole slab without increasing the number of transverse joints.

[0022] As a further improvement of the method of the present invention: in step S2, the designed road surface structure of the transition section 12 includes: a CRC structural layer with variable thickness; extending the steel mesh of the variable slope CRC section to the transition section after the old road is excavated; integrally pouring concrete for the transition section road surface and the CRC section; forming a CRC structure with variable thickness in the transition section; and integrally laying an asphalt functional layer.

[0023] As a further improvement of the method of the present invention: the process in step S2 includes:

[0024] Step S201: Install the formwork; the heights at both ends of the formwork are taken according to the elevation of the concrete layer to be poured;

[0025] Step S202: Extend the steel mesh of the variable slope CRC section to the transition section after the old road is excavated.

[0026] As a further improvement of the method of the present invention: Among the heights at both ends of the formwork, the height L1 at the end connected to the old road is the thickness of the excavated old road slab minus the thickness of the asphalt functional layer to be overlaid; the height L2 at the end connected to the repair and overlay structure is the thickness of the excavated old road slab plus the thickness of the newly overlaid structure, and then minus the thickness of the asphalt functional layer to be overlaid.

[0027] As a further improvement of the method of the present invention: In step S2, the spacing, diameter and grade of the transverse steel bars and longitudinal steel bars, and the same reinforcement design parameters of CRC are adopted. The depth of the steel mesh from the road surface remains unchanged, and it is arranged parallel to the road surface of the transition section, with the height decreasing from high to low, and the height of the steel mesh is controlled by the erection steel bars.

[0028] As a further improvement of the method of the present invention: In step S3, load transfer bars are arranged at the transverse expansion joints. Drill holes on one side of the old cement pavement, and the drilling depth is flush with the longitudinal steel bars, and the spacing is the same as the spacing of the longitudinal steel bars. The section of the load transfer bar buried in the old concrete is coated with epoxy glue.

[0029] As a further improvement of the method of the present invention: In step S3, the setting of the longitudinal construction joint is consistent with the construction of the CRC pavement. The tie bars are replaced by the extension of the transverse steel bars, so the aperture and spacing in the middle of the formwork are determined according to the diameter and spacing of the transverse steel bars.

[0030] As a further improvement of the method of the present invention: The process of step S4 includes:

[0031] Step S401: Control the pouring thickness when re-pouring cement in the formwork, and the reserved thickness is the same as the thickness of the asphalt functional layer on the CRC structure;

[0032] Step S402: According to the designed newly overlaid structure, spread the asphalt functional layer with the corresponding thickness. The asphalt functional layer has good adhesion with the transition slab and the lateral sides of the old road slab, and the joints at both ends are smoothly connected.

[0033] Compared with the prior art, the advantages of the present invention are as follows:

[0034] 1. The end splicing construction method for the separated overlay of the CRC structure on the old cement concrete pavement of the present invention has a simple principle, easy construction, low cost, short construction period and good environmental protection. Based on the idea of making full use of the structural strength of the old road, the CRC pavement structure is overlaid on the old cement pavement. The repaired pavement structure has good adaptability to heavy traffic, convenient and low-cost later maintenance and repair, and the old cement pavement does not need to be crushed and treated, extending the service life of the in-service cement pavement. It is a relatively reasonable and feasible life extension and repair plan.

[0035] 2. The end splicing construction method of the separated CRC overlay structure on the old cement concrete pavement of the present invention effectively solves the technical problem when the elevation of the original old cement pavement at the end of the overlay structure and the joint is inconsistent; this end treatment and construction method is simple and practical, and can solve the problem that the elevation of the CRC structure at the joint exceeds the elevation of the original old road structure after extension and repair, and the problem of setting expansion joints at the end of the CRC slab, thereby improving driving safety and comfort.

[0036] 3. The end splicing construction method of the separated CRC overlay structure on the old cement concrete pavement of the present invention extends the steel mesh of the CRC by changing the slope to the transition section pavement, and the transition section pavement and the CRC section are integrally cast with concrete to form a CRC structure with a changing thickness in the transition section. The pavement end not only plays an anchoring role but also connects naturally, safely and reliably. The steel mesh is set in the transition section to ensure the bearing capacity of the end structure, and load transfer bars are set at the transverse expansion joints connected to the old road to ensure the load transfer capacity of the pavement and the overall deformation coordination. The pavement structure parameters at the splicing location are taken according to the design parameters of the newly built CRC overlay structure, making full use of the existing road construction materials. Compared with the existing technology, the construction procedures and techniques are simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the flow schematic diagram of the method of the present invention in a specific application example.

[0038] Figure 2 is the schematic diagram of the structure principle of the separated CRC pavement overlay on the old cement pavement in a specific application example of the present invention.

[0039] Figure 3 is the schematic diagram of the structure principle of the transition section pavement in a specific application example of the present invention.

[0040] Figure 4 is the schematic diagram of formwork installation, steel bar layout and expansion joint setting in a specific application example of the present invention.

[0041] Figure 5 is the schematic diagram of the structure principle after concrete pouring in a specific application example of the present invention.

[0042] LEGEND DESCRIPTION:

[0043] 1. Transverse steel bar; 2. Longitudinal steel bar; 3. Fine-grained modified asphalt concrete surface layer; 4. SBS modified asphalt synchronous crushed stone seal coat; 5. Continuously reinforced concrete slab; 6. Fine-grained modified asphalt concrete bottom layer; 7. Original cement concrete pavement; 8. Load transfer bar; 9. Transverse expansion joint; 10. Formwork; 11. Formwork for the newly built CRC section; 12. Transition section. DETAILED DESCRIPTION OF THE INVENTION

[0044] The present invention will be further described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0045] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present application.

[0046] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0047] In the present application, unless otherwise clearly specified and defined, the terms "assembled", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0048] A method for end splicing construction after separating and overlaying a CRC structure on an old cement concrete pavement of the present invention is mainly applicable to the renovation and upgrading of traditional cement concrete pavements (original old cement concrete pavements), and specifically discloses an end splicing and construction method for using a separated overlay CRC pavement structure.

[0049] As Figures 1 - 5 shown, the process of the present invention includes:

[0050] Step S1: Determine the pavement length of the transition section 12 and remove the old road slab of the transition section 12;

[0051] Determine the pavement length of the transition section 12 according to the elevation difference between the old road and the newly built pavement joint and the allowable maximum longitudinal slope, and excavate the old road slab of the transition section 12; the old road specifically refers to the original old cement concrete pavement, hereinafter referred to as the "old road";

[0052] Step S2: Construction of the first stage of the transition section 12; By determining the design parameters of each structural layer of the transition section 12, install formwork 10 in the transition section and arrange the steel mesh; The steel mesh includes transverse steel bars 1 and longitudinal steel bars 2;

[0053] Step S3: Construction at the connection between the transition section 12 and the old road; Set a transverse expansion joint 9 with an appropriate width at one end of the transition section 12 where it connects to the old road, and set longitudinal construction joints when constructing in sections;

[0054] Step S4: Construction of the second stage of the transition section 12; According to the designed thickness of each structural layer of the road surface of the transition section 12, pour cement concrete with the corresponding thickness in the formwork 10, and lay an asphalt functional layer after curing.

[0055] In a specific application example, when the transition section 12 has a certain slope, a new CRC section formwork 11 and a steel mesh are provided above the old road at the elevated end.

[0056] In a specific application example, according to the actual application needs, the process of step S1 may include:

[0057] Step S101: Obtain the allowable maximum longitudinal slope value;

[0058] By referring to the current specification "Technical Standards for Highway Engineering" (JTG B01-2014), according to the design speed v in the technical indicators listed in the road surface construction drawing design document, obtain the allowable maximum longitudinal slope value α;

[0059] Step S102: Obtain the shortest length L of the transition section road surface min ;

[0060] Considering the original longitudinal slope α0 of the old road at the joint and the elevation difference H between the old road and the new road surface connection, calculate the shortest length L of the transition section road surface min :

[0061] α' = α ± α0

[0062] L min = H / α'

[0063] Where, when it is an uphill section from the old road to the new road surface, take the "-" sign, and when it is a downhill section, take the "+" sign;

[0064] Step S103: Adjust the length L of the old cement concrete road slab of the transition section 12 to be broken and removed;

[0065] Step S104: After removing the old slab, compact and level the base course.

[0066] Furthermore, as an optimized solution, the following conditions need to be met in step S103:

[0067] (1) It is required that the length of the old road slab to be excavated is not less than the calculated pavement length L of the shortest transition section 12. min ;

[0068] (2) When there are transverse joints in the old cement pavement, the excavated old cement road slab is appropriately extended, and the edge is taken at the original old road transverse joint, and try to excavate the whole slab to avoid increasing the number of transverse joints.

[0069] In a specific application example, according to the actual application needs, in step S2, the pavement design structure of the transition section 12 is: a CRC structural layer with variable thickness; the steel mesh of the variable slope extended CRC section is extended to the transition section 12 after the old road is excavated. The pavement of the transition section 12 and the CRC section are integrally cast with concrete to form a CRC structure with variable thickness in the transition section, and finally an asphalt functional layer is paved as a whole.

[0070] As a preferred solution, in specific applications, the detailed process of step S2 may include:

[0071] Step S201: Install the formwork 10;

[0072] Install the formwork 10 according to the specific dimensions of the cement concrete layer in the pavement structure design drawing. The heights at both ends of the formwork 10 are determined according to the elevation of the concrete layer to be poured;

[0073] Among them, the height L1 at one end connected to the old road is the thickness of the excavated old road slab minus the thickness of the asphalt functional layer to be paved;

[0074] Among them, the height L2 at one end connected to the repair and paving structure is the thickness of the excavated old road slab plus the thickness of the newly paved structure, and then minus the thickness of the asphalt functional layer to be paved.

[0075] The formwork 10 must have sufficient stiffness and should be accurately installed according to the measured elevation, and installed firmly and securely. After installation, any disturbance is prohibited, especially during paving, any collision and vibration are strictly prohibited.

[0076] Step S202: Extend the steel mesh of the variable slope extended CRC section to the transition section 12 after the old road is excavated.

[0077] In the above process, the spacing, diameter and steel bar grade of the transverse steel bar 1 and the longitudinal steel bar 2 all adopt the same reinforcement design parameters of CRC. The depth of the steel mesh from the road surface remains unchanged, and it is arranged parallel to the road surface of the transition section 12, and the height decreases from high to low, and the height of the steel mesh is controlled by the erection steel bar.

[0078] In a specific application example, according to the actual application needs, in step S3, the setting of the transverse expansion joint 9 should meet:

[0079] The width of the transverse expansion joint 9 can be taken as 2 cm according to actual needs, and the expansion joint material is rubber foam board.

[0080] A dowel bar 8 can be further arranged at the transverse expansion joint 9. Drill holes on one side of the old cement pavement. The drilling depth is flush with the longitudinal steel bar 2, and the spacing is the same as that of the longitudinal steel bar 2. The hole diameter is 28 mm and the depth is 35 cm. The dowel bar 8 can be 28 mm in diameter and 70 cm in length according to actual needs. One section of the dowel bar 8 buried in the old concrete is coated with epoxy glue, and the buried depth is 35 cm according to actual needs.

[0081] The setting of the longitudinal construction joint is consistent with the CRC pavement construction. The tie bar is generally replaced by the extension of the transverse steel bar. Therefore, the hole diameter and spacing in the middle of the formwork 10 should be determined according to the diameter and spacing of the transverse steel bar 1.

[0082] In a specific application example, according to the actual application needs, in step S4, the second-stage construction of the transition section 12 includes the paving of a cement concrete layer and an asphalt functional layer, which specifically includes:

[0083] Step S401: Control the pouring thickness when re-pouring cement in the formwork 10. The reserved thickness is the same as the thickness of the asphalt functional layer on the CRC structure.

[0084] Step S402: Pave the asphalt functional layer with the corresponding thickness according to the designed new paving structure. The asphalt functional layer should be well bonded to the transition board and the transverse side of the old road board, and the two ends should be smoothly connected.

[0085] The following will further illustrate the present invention in detail with a specific application example.

[0086] In this embodiment, the specific calculation parameters for the overlay of CRC structure on the old cement concrete pavement are as follows: Design speed: 60 km / h (40 km / h in the town section), road width 10.5 m, the old cement concrete pavement 7 is a 30-cm C35 cement concrete panel, and the pavement structure form after life extension and repair: old cement pavement 7 + 3-cm AC-10 fine-grained modified asphalt concrete lower layer 6 + 18-cm continuously reinforced concrete 5 + 1-cm SBS modified asphalt synchronous crushed stone seal coat 4 + 5-cm AC-13 fine-grained modified asphalt concrete lower layer 3. The old cement pavement overlay with CRC + AC pavement structure is as Figure 2 shown. The pavement elevation after life extension and repair has increased by 27 cm. Improper treatment will affect driving comfort and driving safety. The detailed steps of the end treatment method for the separated overlay of CRC structure on the old cement pavement in this embodiment are as follows:

[0087] Step S1000: According to the design speed v = 60 km / h (40 km / h in the market town section) listed in the technical indicators in the road surface construction drawing document, referring to the current specification "Technical Standard for Highway Engineering" (JTG B01 - 2014), since the road section at the joint is not in the market town section, the maximum longitudinal slope α = 7% is determined; from the on - site measurement data, the original longitudinal slope of the old road at the joint α0 = 1%, and the slope rises along the driving direction.

[0088] Step S2000: Substitute the original longitudinal slope α0 of the old road at the joint and the CRC structure thickness H = 27 cm in the road surface overlay structure design drawing (see Figure 2 ) into the following formula to obtain the length L of the transition section 12 road surface min :

[0089] α' = α ± α0

[0090] L min = H / α'

[0091] Where, when it is an uphill section from the old road to the new road surface, take the "-" sign, and when it is a downhill section, take the "+" sign;

[0092] After calculation, L min = 450 cm.

[0093] Step S3000: Appropriately extend the length of the old road slab to be excavated. The edge of the old cement road slab in the transition section 12 to be excavated is adjusted at the nearest transverse joint, and try to excavate the whole slab without increasing the number of transverse joints. After adjustment, the length of the old road slab in the transition section 12 to be excavated is L = 500 cm, and both sides of the old road slab to be excavated are old road transverse joints. After excavating the old slab, compact and level the base course.

[0094] Step S4000: Refer to the new CRC + AC section road surface structure to determine the design parameters of each structural layer of the transition section 12 road surface. The road surface structure of the transition section 12 is a compacted base course, a continuously reinforced concrete layer 5 with variable thickness (24 - 33 cm), a 1 - cm - thick SBS modified asphalt synchronous chip seal layer 4, and a 5 - cm - thick AC - 13 fine - grained modified asphalt concrete surface layer 3, as Figure 3 shown.

[0095] Step S5000: As Figure 4As shown in the installation template 10, the height L1 of the template 10 at one end connected to the old road is the thickness of the removed old road slab, which is 30 cm, minus the thickness of the asphalt functional layer to be overlaid, which is 6 cm (1 cm of synchronous crushed stone layer + 5 cm of AC-13). L1 is taken as 24 cm. The height L2 of the template 10 at one end connected to the newly built CRC structure is the thickness of the removed old road slab, which is 30 cm, plus the thickness of the newly overlaid CRC structure, which is 21 cm (3 cm of AC-10 fine-grained modified asphalt concrete bottom layer 6 + 18 cm of continuously reinforced concrete 5). L2 is taken as 51 cm. The template 10 must have sufficient stiffness and should be accurately installed according to the measured elevation, and be installed firmly and securely. After installation, disturbance is prohibited, especially during paving, collision and vibration are strictly prohibited.

[0096] Step S6000: Extend the steel bar mesh of the CRC section to the transition section 12. The spacing, diameter and steel bar grade of the transverse steel bars 1 and longitudinal steel bars 2 adopt the same reinforcement design parameters as those of the newly built CRC section. For example, the longitudinal steel bar 2 is φ16@18.5, the transverse steel bar 1 is φ12@62, and the steel bar grade is HRB335. The steel bar mesh is arranged parallel to the road surface of the transition section 12 at a depth of 9 cm from the surface of the cement concrete, and the height is from high to low, and the height of the steel bar mesh is controlled by the erection steel bars.

[0097] Step S7000: Set a transverse expansion joint 9 with an appropriate width at one end of the transition section 12 connected to the old road. The width of the expansion joint is taken as 2 cm, and the expansion joint material is selected as rubber foam board. A load transfer bar 8 is set at the expansion joint. Drill holes on the side of the old cement pavement, the drilling depth is 18 cm, the spacing is the same as the spacing of the longitudinal steel bars 2, which is 18.5 cm, the hole diameter is 28 mm, and the depth is 35 cm. The load transfer bar 8 has a diameter of 28 mm and a length of 70 cm. The section of the load transfer bar 8 buried in the old concrete is coated with epoxy glue, and the buried depth is 35 cm.

[0098] Set longitudinal construction joints. The setting of the longitudinal construction joints is the same as that of the CRC pavement construction. The tie bars are replaced by the extension of the transverse steel bars 1. According to the diameter and spacing of the transverse steel bars 1, the diameter of the hole in the middle of the template 10 is determined to be 12 mm, and the spacing is 62 cm. [[ID=]]

[0099] Step S8000: As Figure 5 shown, pour concrete. Pour the cement concrete with the designed thickness in the installed template 10. The transition section 12 and the CRC section are poured integrally, and a CRC structure with a changing thickness is formed in the transition section 12. No additional transverse joints are provided between the transition section 12 and the CRC section; after curing for 28 days, according to the designed CRC structure, the corresponding thickness of the asphalt functional layer is integrally overlaid. The asphalt functional layer includes 1 cm of SBS modified asphalt synchronous crushed stone layer 4 and 5 cm of AC-13 fine-grained modified asphalt concrete surface layer 3, so that the joints at both ends are smoothly connected.

[0100] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.

Claims

1. A method for end splicing after separating and overlaying a CRC structure on an old cement concrete pavement, characterized in that, Including: Step S1: Determine the pavement length of the transition section and remove the old road slabs of the transition section; determine the pavement length of the transition section according to the elevation difference at the joint between the old road and the newly built pavement and the allowable maximum longitudinal slope; Step S2: Construction in the first stage of the transition section; by determining the design parameters of each structural layer of the transition section, install formwork in the transition section and arrange the steel mesh; the steel mesh includes transverse steel bars and longitudinal steel bars; Step S3: Construction at the joint between the transition section and the old road; set a transverse expansion joint with an appropriate width at one end where the transition section is connected to the old road, and set longitudinal construction joints when constructing in sections; Step S4: Construction in the second stage of the transition section; according to the designed thickness of each structural layer of the pavement in the transition section, pour cement concrete with the corresponding thickness in the formwork, and lay an asphalt functional layer after curing; The process of the said Step S1 includes: Step S101: Obtain the allowable maximum longitudinal slope value α; Step S102: Obtain the shortest length of the transition section pavement L min ; Considering the longitudinal slope α0 of the original old road at the joint and the elevation difference H between the old road and the new pavement at the splicing location, calculate the shortest length of the transition section pavement L min : Wherein, when it is an uphill section from the old road to the newly built pavement, take the "-" sign, and when it is a downhill section, take the "+" sign; Step S103: Adjust and break and remove the length L of the old cement road slab in the transition section; Step S104: After removing the old slab, tamp and level the base course.

2. The end splicing method after separating and overlaying CRC structure on the old cement concrete pavement according to claim 1, characterized in that, In the said Step S103, the following conditions are met: (1) It is required that the length of the old road slab to be dug out is not less than the pavement length of the calculated shortest transition section. L min ; (2) When there are transverse joints in the old cement pavement, the removed old cement road slab is appropriately extended, and the edge is taken at the original transverse joint of the old road, so as to remove the whole slab without increasing the number of transverse joints.

3. The end splicing method after separating and overlaying the CRC structure on the old cement concrete pavement according to claim 1 or 2, characterized in that, In the said Step S2, the designed pavement structure of the transition section includes: a CRC structural layer with variable thickness; extend the steel mesh of the CRC section with variable slope to the transition section after the old road is removed; pour concrete integrally for the pavement of the transition section and the CRC section; form a CRC structure with variable thickness in the transition section; lay an asphalt functional layer integrally.

4. The end splicing method after separating and overlaying the CRC structure on the old cement concrete pavement according to claim 1 or 2, characterized in that, The process in the said Step S2 includes: Step S201: Install formwork; the heights at both ends of the formwork are taken according to the elevation of the concrete layer to be poured; Step S202: Extend the steel mesh of the CRC section with variable slope to the transition section after the old road is removed.

5. The end splicing method after the separated overlay of CRC structure on the old cement concrete pavement according to claim 4, characterized in that, Among the heights at both ends of the formwork, the height L1 at the end connected to the old road is the thickness of the removed old road slab minus the thickness of the asphalt functional layer to be laid; the height L2 at the end connected to the repair and overlay structure is the thickness of the removed old road slab plus the thickness of the newly laid structure, and then minus the thickness of the asphalt functional layer to be laid.

6. The end splicing method after separating and overlaying CRC structure on the old cement concrete pavement according to claim 1 or 2, characterized in that, In the said Step S2, the spacing, diameter and steel bar grade of the transverse steel bars and longitudinal steel bars all adopt the same reinforcement design parameters of CRC. The depth of the steel mesh from the road surface remains unchanged, and it is arranged parallel to the road surface of the transition section. The height decreases from high to low, and the height of the steel mesh is controlled by the erection steel bars.

7. The end splicing method after separating and paving the CRC structure on the old cement concrete pavement according to claim 1 or 2, characterized in that, In the said Step S3, load transfer bars are set at the transverse expansion joint, drill holes on one side of the old cement pavement, the drilling depth is flush with the longitudinal steel bars, and the spacing is kept consistent with the spacing of the longitudinal steel bars. The section of the load transfer bar buried in the old concrete is coated with epoxy glue.

8. The end splicing method after separating and overlaying the CRC structure on the old cement concrete pavement according to claim 1 or 2, characterized in that, In the said Step S3, the setting of the longitudinal construction joint is consistent with the construction of the CRC pavement. The tie bars are replaced by the extension of the transverse steel bars, so the hole diameter and spacing in the middle of the formwork are determined according to the diameter and spacing of the transverse steel bars.

9. The end splicing method after separating and overlaying CRC structure on the old cement concrete pavement according to claim 1 or 2, characterized in that, The process of the said Step S4 includes: Step S401: Control the pouring thickness when re-pouring cement in the template, and the reserved thickness is the same as the thickness of the asphalt functional layer on the CRC structure; Step S402: According to the designed newly paved structure, pave the asphalt functional layer with the corresponding thickness. The asphalt functional layer has good adhesion with the transition plate and the lateral sides of the old road plate, and the joints at both ends are smooth and natural.

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