CN106436525B - A kind of old concrete road surface inhibits the composite construction and remodeling method of reflection crack - Google Patents

Abstract

The invention discloses a composite structure for suppressing reflection cracks on old cement concrete pavement, which comprises a base, an old cement face plate laid on the base, and an asphalt concrete overlay layer laid on the old cement face; The multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer between the face plate and the asphalt concrete overlay; the asphalt concrete overlay includes medium-grain asphalt concrete underlayer, modified emulsified asphalt bonded layer laid in sequence from bottom to top layer and the upper layer of asphalt mastic macadam; also discloses a reconstruction method for the composite structure of the old cement concrete pavement suppressing reflective cracks, including locally constrained steel bar molding, planting bars, and completing multi-scale hybrid fiber reinforced epoxy asphalt macadam Sealing layer, the invention can improve the overall bearing capacity of the pavement reformed by using the old cement face layer, effectively improve the good interlayer bonding force between the old cement face layer and the asphalt concrete overlay layer, and suppress the generation of reflection cracks and the addition of asphalt concrete. Layer extension.

Description

A Composite Structure for Restraining Reflective Cracks on Old Cement Concrete Pavement and Its Reform Method

technical field

The invention belongs to the technical field of road and traffic engineering, and in particular relates to a composite structure for suppressing reflection cracks on an old cement concrete pavement and a reconstruction method.

Background technique

Since the 1990s, China has built a large number of cement concrete roads. With the rapid development of national economic construction, the load and density of vehicles on urban roads and national highways are increasing, and heavy loads and overloading are common, resulting in increasingly serious damage to cement concrete pavements. At present, most cement concrete pavements are in the period of overhaul. Adding asphalt concrete pavement on the old cement concrete pavement is the main form of old cement pavement reconstruction, but this kind of composite pavement structure is very easy to cause stress concentration in the asphalt concrete overlay layer above the joint between the old cement concrete pavement slabs. Create reflective cracks.

Existing studies have shown that the occurrence of reflective cracks is inevitable and cannot be completely eliminated, and only measures can be taken to delay or inhibit its development. Temperature stress, traffic load and their coupling effects are important causes of cracking of asphalt concrete overlay. The traffic load mainly causes the shear reflection cracks of the overlay layer. Under the action of the wheel load, the deflection difference on both sides of the old cement concrete slab joint is too large, which causes the shear failure of the asphalt overlay layer and gradually expands upward. Formation of load-type reflective cracks. The temperature change mainly causes the open reflective cracks in the asphalt overlay. The temperature change causes two deformations in the pavement structure. One is that the asphalt overlay and the old cement concrete panels at the joints shrink due to the temperature drop, which causes open reflective cracks. The other is that there is a temperature gradient in each structural layer due to the temperature difference between day and night, and different materials have different thermal expansion coefficients, which cause the shrinkage and warping of the old cement concrete pavement and asphalt overlay, which causes reflection cracks in the asphalt overlay.

Most of the existing technical measures to prevent reflective cracks focus on the design of the asphalt overlay structure, including: (1) increasing the thickness of the asphalt overlay; (2) adding geogrid or geotextile as a waterproof layer; (3) Utilize the bonding and interlocking effect of the reinforced material to add mesh reinforcing ribs; (4) Add a stress absorbing layer, such as setting a stress absorbing layer of open-graded large-size asphalt macadam; (5) Add cement concrete crushed stone Pave asphalt concrete surface, etc. Schemes (1) and (4) can effectively reduce the maximum principal tensile stress and maximum shear stress at the bottom of the asphalt concrete overlay structure by increasing the thickness of the asphalt concrete overlay, but cannot effectively slow down the crack propagation speed and prevent reflection cracks production and development. At the same time, the method of increasing the thickness of the asphalt overlay layer is difficult to meet the restrictions on the elevation of the urban road surface, and also increases the total cost of the road surface, and in the case of high temperature in summer, the high temperature creep of the asphalt mixture is easy to produce ruts, and it is lost due to the old cement concrete. The advantage of the strong base and thin surface produced by using the board as the base. The application results of schemes (2) and (3) show that the effect on load-type reflective cracks is limited, and it is not conducive to the interlayer shear resistance, bonding and waterproofing of the overlay composite structure. Option (5) is noisy, which is not conducive to the repair and reconstruction of urban roads.

The purpose of setting joints between cement concrete pavement blocks is to eliminate the temperature stress caused by temperature changes and prevent pavement damage caused by temperature changes. However, from the point of view of the load bearing of the cement concrete road slab, the existence of the joint between the slabs weakens the integrity of the concrete slab. The more obvious the stress concentration of the cement panel block, the more serious the reflective crack disease is.

As far as the composite structure of the old cement concrete pavement is paved with asphalt pavement, the occurrence of reflection cracks is inevitable, and measures can only be taken to delay or inhibit its development and reduce its damage. The results of numerical calculation and analysis show that under the repeated action of environmental factors and traffic loads, the relative vertical displacement difference (deflection difference) of the two sides of the old cement concrete slab joint is too large, which not only leads to excessive stress on the bottom surface of the asphalt layer And cracking, and cause the shear stress between the old concrete pavement and the asphalt overlay layer to increase rapidly, resulting in the failure of the bonding layer. Once the cracks are formed, the cracks quickly expand to the surroundings, and the water penetrates into the base layer through the cracks, causing damage to the base material under repeated driving loads, which in turn causes diseases such as mud turning, mud pumping, and subsidence. Therefore, strictly controlling the deflection difference at the joints of the old cement pavement and increasing the shear resistance of the interface between the original cement board and the asphalt overlay are effective measures to prevent and reduce the reflection cracks. At the same time, the waterproof ability of the bonding layer between the original cement slab surface and the asphalt overlay surface is enhanced to prevent water from penetrating into the base layer through cracks and causing further crack expansion.

Chinese Patent No. CN201510077194.X discloses a joint construction method to prevent asphalt reflection cracks on old cement pavement. First, the deflection difference between the old concrete panels that need joint reinforcement is measured. Cut strip-shaped grooves at equal intervals across the joints of the concrete panels, and then use a percussion drill to vertically drill the ends of the strip-shaped grooves; , to complete the forming of the horseshoe tendon; after implanting the horseshoe-shaped steel bar in the strip groove and the vertical hole at the end, pour epoxy resin planting glue into the drilled hole after cleaning the hole; and mix cement and gravel concrete pouring, It is poured into the groove to form a protective layer of planting bars; several layers of protective coverings are laid on the upper layers of the two old concrete panels from bottom to top. The invention has the advantages of preventing the generation and development of reflection cracks by reducing the relative vertical displacement on both sides of the old slab seam, thereby reducing or preventing the occurrence of reflection cracks in the asphalt surface layer added to the old cement road surface. However, the planting bars connecting the cracks between the cement concrete slabs are isolated, and the horizontal direction has not formed a "network". The effect of lateral vertical displacement difference. The toughness of the old cement pavement transformed by this joint construction method is not strong enough, the overall shear resistance and overall tensile strength are relatively poor, the effect of inhibiting reflective cracks is not good, the waterproof performance is poor, and the formation of reflective cracks is easy to cause water damage.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art, and now provide a composite structure and a transformation method for suppressing reflection cracks on old cement concrete pavement, so as to solve the problem that the toughness of the road surface is not strong enough, the overall shear resistance and the overall tensile strength are relatively poor, and the inhibition The effect of reflective cracks is not good, and the waterproof performance is poor. After the formation of reflective cracks, it is easy to cause water damage.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a composite structure for suppressing reflective cracks on an old cement concrete pavement, comprising a base, an old cement face layer and an asphalt concrete overlay laid on the cement face layer; The old cement panel layer includes several old cement panel units; the old cement panel unit includes old cement panels arranged in double rows and double columns; A multi-scale hybrid fiber reinforced epoxy asphalt macadam seal layer; the asphalt concrete overlay layer includes a medium-grain asphalt concrete underlayer, a modified emulsified asphalt adhesive layer and an asphalt mastic macadam top layer laid in sequence from bottom to top layer; the horizontally arranged old cement panels are provided with inter-board transverse joints, and the longitudinally arranged old cement panels are provided with inter-board longitudinal joints; The seam is connected with the longitudinal joint between the boards; the old cement panel layer is engraved with a broken line groove; the broken line shaped groove is arranged at the transverse joint between the boards, and runs through the entire old cement panel layer longitudinally; The zigzag groove is provided with a zigzag local restraint steel bar matched with it.

Further, the zigzag-shaped local restraint steel bar is a threaded steel bar with a diameter of 25-35 mm; the zigzag-shaped local restraint steel bar is set in the shape of a trapezoidal wave, including being arranged on the left and right sides of the transverse joint between the plates respectively, with the same shape, and Trapezoid whose bottom edge is continuously connected successively along the direction of the transverse joint between the slabs; the lateral width of the left and right sides of the folded line-shaped local restraint reinforcement is 2*a+d ⁰ , wherein the d ⁰ is the transverse joint between the cement slabs Width, the range of a is 400-500mm; the outermost width of the broken-line locally constrained reinforcement trapezoidal wave protrusion is 2*b+z ⁰ , where z ⁰ is the width of the longitudinal joint between plates, The range of b is 300-400mm; the width of one cycle of the trapezoidal wave of the zigzag locally constrained reinforcement is 3*c+b, wherein the range of c is 500-600 mm.

The technical scheme also adopted in the present invention is: a transformation method for suppressing reflection cracks on old cement concrete pavement, and its innovative point is that it includes the following steps:

(1) Forming of broken-line locally restrained steel bars: select threaded steel bars, bend the threaded steel bars into the required broken-line shape according to the width of the transverse joint between the plates and the width of the longitudinal joint between the plates, and complete the described Broken-line local restraint reinforcement forming;

(2) Deflection pretreatment of old cement panels: measure deflection difference between panels for old cement panels that need joint reinforcement, and select old cement panels with measured deflection difference ≤ 0.06mm;

(3) Reinforcement pretreatment: For the selected old cement panels whose measured deflection difference is ≤0.06mm, perform pretreatment of rebar planting, and the additional stress concentration area of the vehicle load at the transverse joint between the panels of the old cement panels , that is, at the range of 400-500mm on both sides of the transverse joint between the plates, a broken-line groove is cut across the joint. The depth is 50-70mm, and the zigzag groove is set as the planting bar; use a blower to purge the zigzag groove;

(4) Fabrication of planting bars and planting bar protection layer: implant local restraint steel bars into the broken line groove; use the mixed crushed stone concrete filler to pour into the remaining space between the inner side of the broken line shaped groove and the local restraint steel bar;

(5) Epoxy asphalt spraying: Use a special epoxy asphalt supply vehicle to transport the epoxy asphalt to the construction site for epoxy asphalt spraying, spray evenly, and manually spray the unsprayed areas;

(6) Preparation of gravel containing multi-scale mixed fibers: select basalt gravel with equal particle size, fine fibers for crack resistance and thick fibers for reinforcement; dry mix the selected materials until the fine fibers for crack resistance and reinforcement Mix coarse fiber and gravel evenly;

(7) Spreading gravel containing multi-scale hybrid fibers: use a spreader to evenly spread gravel containing multi-scale hybrid fibers on the epoxy asphalt; the step (5), the step (6) and the Step (7) completing the laying of the multi-scale hybrid fiber-reinforced epoxy asphalt gravel seal;

(8) Lay the lower layer: use medium-grained asphalt concrete, and lay the lower layer of medium-sized asphalt concrete within 24h-48h of the multi-scale hybrid fiber-reinforced epoxy asphalt crushed stone seal layer spraying;

(9) Laying the adhesive layer: use modified emulsified asphalt, and lay the modified emulsified asphalt adhesive layer on the lower layer;

(10) Laying the upper layer: use asphalt mastic macadam, and lay the upper layer of asphalt mastic macadam on the bonding layer.

Further, after the measurement of the deflection difference between the panels in the step (2), the old cement panel with a measured value of the deflection difference > 0.06, before performing the step (3), the old cement panel is grouted; the grouting treatment The grouting material is cement mortar, and the ratio of cement mortar is: 1.0:5.

Further, in the step (5), the spraying amount of the epoxy asphalt is 0.7-0.8kg/㎡, and the temperature of the epoxy asphalt is 120°C.

Further, in the step (6), the crack-resistant fine fibers are set to one or more of polyvinyl alcohol fibers, polyacrylonitrile or polyester fibers; the diameter of the crack-resistant fine fibers is 0.02-0.04mm, the length is 6-12mm, and the volume ratio of fine fibers is 2%-3%; the thick fiber for reinforcement is set as a circular section polypropylene monofilament; the diameter of the thick fiber for reinforcement is 0.15-0.30 mm, the length is 10-20mm, the density is 0.91g/cm ³ , the volume ratio of crude fiber is 1%-2%; the dry mixing speed is 1200r/min, and the dry mixing time is 30s.

Further, in the step (6), the size of the selected basalt gravel is 4.75-9.5mm, and the dosage is 6kg/m ² ; Coverage > 70%.

Further, the thickness of the multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer is 0.8cm; the medium-grain asphalt concrete lower layer is AC-16C medium-grain asphalt concrete with a thickness of 6cm; The upper layer of asphalt mastic macadam is SMA-13 type of asphalt mastic macadam with a thickness of 4cm; the modified emulsified asphalt bonding layer is used to bond the lower layer of medium-grained asphalt concrete and asphalt mastic The top layer of gravel.

Further, in the step (4), the strength grade of the gravel concrete filler is C20-C40.

The beneficial effects of the present invention are as follows:

1. The present invention makes full use of the remaining strength of the old cement panel layer by setting local restraint structural steel bars, reduces the value of the deflection difference on both sides of the transverse joint between the panels of the old cement panel and blocks the reflection cracks between the panels to the upper asphalt concrete The channel for overlay expansion; through the different diameter fiber reinforcement, toughening and crack resistance of thick fibers for reinforcement and fine fibers for crack resistance, the overall shear strength of the interface between the old cement face plate layer and the asphalt concrete overlay layer is improved and waterproof performance, prevent and delay the generation and development of reflective cracks, and then reduce or prevent the occurrence of reflective cracks on the asphalt concrete overlay; The old cement panel layer and the asphalt concrete overlay layer have good interlayer bonding force, which inhibits the generation and expansion of reflective cracks.

2. The present invention implements local restraint between the plates by setting broken-line local restraint steel bars at the transverse joints between the old cement panels, so that the stress redistribution and coordinated deformation between the old cement panels under the action of traffic load and temperature , improve the overall shear capacity and the overall tensile strength of the composite structure of the old cement face layer plus the concrete overlay layer, and give full play to the remaining strength of the old cement face layer. A "bolt-lock" effect is formed between the locally restrained steel bars and the old cement panel layer, which reduces the width of the cracks formed by the longitudinal joints and transverse joints between the panels of the old cement panel due to the driving load and temperature, and The passage of reflective cracks between the old cement panels to the upper asphalt overlay was blocked.

3. In the old cement panel layer in the present invention, under the action of traffic load and temperature, the affected area of the reflective crack at the transverse joint between the panels of the old cement panel is embedded with local restraint structural steel bars, which reduces the temperature shrinkage horizontal stress of the old cement panel , the vertical stress and warping deformation of the driving load, and make full use of the remaining strength of the old cement panel layer to block the launch channel of the reflective cracks between the old cement panels.

4. The present invention designs a multi-scale hybrid fiber-reinforced epoxy asphalt gravel seal between the old cement face plate and the asphalt concrete overlay. The multi-scale hybrid fiber-reinforced epoxy asphalt macadam sealant not only has interlayer interface bonding ability, but also has good waterproof performance, which can avoid water damage caused by the formation of reflective cracks. In the multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal, the multi-scale hybrid fibers play the role of bridging and crack resistance of fibers with different diameters, and further inhibit the failure of interlaminar shear stress caused by reflective cracks.

5. The multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer in the present invention, the crushed stone is mixed with an appropriate amount of thick fiber for reinforcement and fine fiber for crack resistance, and the macadam containing multi-scale hybrid fiber is formed to form 2 roads of anti-corrosion. Crack prevention line, which effectively improves the interlayer shear and fracture performance of multi-scale hybrid fiber reinforced epoxy asphalt macadam seal, and improves the waterproof ability between the old cement face layer and the asphalt overlay layer, preventing shear reflection Cracks and water damage to the base.

Description of drawings

Fig. 1 is a schematic diagram of the planar arrangement position of the locally constrained reinforcement in the present invention.

Fig. 2 is a schematic diagram of the structural layout of the transverse joints between the old cement panel boards in the present invention.

Detailed ways

The implementation of the present invention will be illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

As shown in Figures 1 and 2, the present invention discloses a composite structure for suppressing reflective cracks on an old cement concrete pavement, including a base layer 6, an old cement panel layer 5 laid on the base layer 6, and an old cement panel layer laid on the old cement panel layer. Asphalt concrete overlay; the old cement panel layer 5 includes several old cement panel units; the old cement panel unit includes old cement panels 11 arranged in double rows and double columns; also includes laying between the old cement panel layer 5 and the asphalt concrete overlay layer The multi-scale hybrid fiber reinforced epoxy asphalt macadam seal layer 4 between them; the asphalt concrete overlay layer includes medium-grain asphalt concrete underlayer 3, modified emulsified asphalt adhesive layer 2 and asphalt mastic laid in sequence from bottom to top The upper layer 1 of gravel; the horizontal joints 7 are arranged between the old cement panels 11 arranged horizontally, and the longitudinal joints 10 are arranged between the old cement panels 11 arranged vertically; the old cement panel units pass through the board The horizontal joint 7 between the boards is connected with the longitudinal joint 10 between the boards; the old cement panel layer 5 is engraved with a broken line groove 8; The panel layer 5; the zigzag-shaped local restraint steel bar 9 matching it is arranged in the zigzag groove 8 .

The broken-line local restraint steel bar 9 is a threaded steel bar with a diameter of 25-35mm; the broken-line local restraint steel bar 9 is set in the shape of a trapezoidal wave, including being arranged on the left and right sides of the transverse joint 7 between the plates respectively, with the same shape, and the bottom edge of the trapezoidal plate Trapezoids connected continuously in the direction of the transverse joint 7; the lateral width of the left and right sides of the broken-line local restraint reinforcement 9, that is, the distance from the upper bottom of the left trapezoid to the upper bottom of the right trapezoid is 2*a+d ⁰ , where, The d ⁰ is the width of the transverse joint 7 between the cement boards, and the range of a is 400-500mm; the width of the outermost side of the folded-line local restraint reinforcing bar 9 trapezoidal wave bulge, that is, the width of the upper bottom of the trapezoid is 2*b+z ⁰ , where z ⁰ is the width of the longitudinal joint 10 between the plates, and the range of b is 300-400mm; the width of one period of the trapezoidal wave of the broken-line local restraint reinforcement 9, that is, the sum of the lower bottoms of the two trapezoids is 3*c+ b, where the range of c is 500-600 mm.

Example 1

A reconstruction method for suppressing reflective cracks on an old cement concrete pavement, comprising the following steps:

(1) Forming of broken-line local restraint steel bar 9: select threaded steel bar, bend the threaded steel bar into the required broken-line shape according to the width of the transverse joint 7 between the plates and the width of the longitudinal joint 10 between the plates, Complete the forming of the zigzag locally constrained steel bar 9;

(2) Deflection pretreatment of old cement panels 11: measure deflection difference between panels for old cement panels 11 that need joint reinforcement, and select old cement panels 11 with measured deflection difference ≤ 0.06mm;

(3) Reinforcement pretreatment: For the selected old cement panels 11 whose measured value of deflection difference is less than or equal to 0.06mm, perform pretreatment of rebar planting, and the additional stress concentration area of the vehicle load at the joints of the old cement panels 11, namely At the range of 400-500mm on both sides of the transverse joint 7 between the panels, a broken-line groove 8 is cut across the joint. The depth of the groove 8 is 50-70mm, and the zigzag groove 8 is set as the bar planting part; the zigzag groove is purged with a blower;

(4) Production of rebar planting and rebar planting protection layer: implant local restraint steel bar 9 into broken line groove 8; use crushed stone concrete filler that has been stirred to pour between the inner side of broken line shape groove 8 and local restraint steel bar 9 In the remaining space; the strength grade of crushed stone concrete filler is C20-C40.

In the present invention, local restraint between the plates is provided by providing broken line-shaped local restraint steel bars 9 at the transverse joints 7 between the old cement panels 11, so that the stress redistribution between the plates of the old cement panels 11 under the action of traffic load and temperature And coordinated deformation, improve the overall shear capacity and overall tensile strength of the composite structure of the old cement face layer 5 overlaying the asphalt concrete overlay layer, and give full play to the remaining strength of the old cement face layer 5. A "bolt lock" effect is formed between the locally restrained steel bars 9 and the old cement panel layer 5, which reduces the width of the crack 7 at the longitudinal joint 10 and the transverse joint between the panels of the old cement panel 5, and blocks the Channels where reflective cracks between panels of old cement panels 11 propagate toward the upper asphalt overlay. In the old cement panel layer 5, under the action of traffic load and temperature, the affected area of the reflective crack at the inter-board transverse joint 7 of the old cement panel is embedded with local restraint steel bars 9, which reduces the temperature shrinkage horizontal stress and traffic load of the old cement panel 11 vertical stress and warping deformation, and make full use of the remaining strength of the old cement panel layer 5 to block the launch channel of the reflective cracks between the old cement panels 11 .

(5) Spray epoxy asphalt: Use a special epoxy asphalt supply vehicle to transport the epoxy asphalt to the construction site for epoxy asphalt spraying, spray evenly, and artificially spray the unsprayed areas; the spraying amount of epoxy asphalt is 0.7-0.8kg/㎡, the temperature of epoxy asphalt is 120℃.

(6) Preparation of gravel containing multi-scale mixed fibers: select basalt gravel with equal particle size, fine fibers for crack resistance and thick fibers for reinforcement; dry mix the selected materials until the fine fibers for crack resistance and reinforcement Mix coarse fiber with crushed stone evenly; the size of the selected basalt crushed stone is 4.75-9.5mm, and the dosage is 6kg/m ² . The fine fiber for crack resistance is one or more of polyvinyl alcohol fiber, polyacrylonitrile or polyester fiber; the diameter of the fine fiber for crack resistance is 0.02-0.04mm, the length is 6-12mm, and the volume ratio of the fine fiber is 2%-3%; the thick fiber for reinforcement is polypropylene monofilament with circular cross-section; the diameter of the thick fiber for reinforcement is 0.15-0.30mm, the length is 10-20mm, the density is 0.91g/cm ³ , the volume of the thick fiber The rate is 1%-2%; the speed of dry mixing is 1200r/min, and the time of dry mixing is 30s.

(7) Spreading gravel containing multi-scale hybrid fibers: Use a spreader to evenly spread gravel containing multi-scale hybrid fibers on the epoxy asphalt; the coverage rate of gravel containing multi-scale hybrid fibers is >70%; steps (5), step (6) and step (7) complete the laying of the multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer 4 .

(8) Lay the lower layer: choose medium-grain asphalt concrete, and lay the medium-grain asphalt concrete lower layer 3 within 24h-48h of the multi-scale hybrid fiber-reinforced epoxy asphalt crushed stone seal layer spraying and forming;

(9) Laying the adhesive layer: use modified emulsified asphalt, and lay the modified emulsified asphalt adhesive layer 2 on the lower layer;

(10) Laying the upper layer: use asphalt mastic macadam, and lay the upper layer 1 of asphalt mastic macadam on the bonding layer. The thickness of the multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer 4 is 0.8cm; the medium-grained asphalt concrete lower layer 3 is AC-16C medium-grained asphalt concrete with a thickness of 6cm; the asphalt mastic Asphalt mastic macadam of SMA-13 type is selected as the upper layer 1 of the fat macadam, and the thickness is 4cm; the modified emulsified asphalt bonding layer 2 is used to bond the lower layer 3 of the medium-grained asphalt concrete and the asphalt mastic Layer 1 above gravel.

The present invention designs a multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer 4 between the old cement face plate layer 5 and the asphalt concrete overlay layer. The multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer 4 not only has interlayer interface bonding ability, but also has good waterproof performance, which can avoid water damage caused by the formation of reflective cracks. The multi-scale hybrid fibers in the multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer 4 play the role of bridging and crack resistance of fibers with different diameters, and further suppress the failure of interlaminar shear stress caused by reflective cracks. In the multi-scale hybrid fiber-reinforced epoxy asphalt macadam seal layer 4 in the present invention, an appropriate amount of thick fibers for reinforcement and fine fibers for crack resistance are mixed into the crushed stones to form two crack-resistant cracks containing multi-scale hybrid fibers. The defense line effectively improves the interlayer shear and fracture performance of the multi-scale hybrid fiber reinforced epoxy asphalt macadam seal, and improves the waterproof ability between the old cement panel layer 5 and the asphalt overlay layer, preventing shear reflection Cracks and water damage to the base.

Example 2

The difference between Example 2 and Example 1 is that after the deflection difference between panels is measured in step (2), the old cement panel 11 whose measured value of deflection difference is > 0.06, before step (3). Cement panel 11 grouting treatment; the grouting material of the grouting treatment is cement mortar, the proportion of cement mortar is: 1.0:5, compressive strength ≥ 15Mpa, and based on the total mass of cement mortar, add 0.001wt% of aluminum powder, Early strength agent 0.01wt%. Through grouting treatment and adding aluminum powder early strength agent, etc., the deflection difference between the boards is reduced to less than 0.06mm, which reduces the additional stress caused by the void at the bottom of the board, and prevents the deflection difference between the boards from being too large, resulting in reflections on the road surface after renovation crack phenomenon.

The present invention makes full use of the residual strength of the old cement panel layer by arranging local restraint structural steel bars 9, reduces the deflection difference on both sides of the transverse joint 7 between the old cement panels 11, and blocks the reflective cracks between the panels to add asphalt concrete to the upper part The channel of layer expansion; through the reinforcement, toughening and anti-cracking effect of different diameter fibers of thick fibers and crack-resistance fine fibers, the shear strength of the interface between the old cement panel layer 5 and the asphalt concrete overlay layer is improved, and waterproof performance, preventing and delaying the generation and development of reflective cracks, and then reducing or preventing the occurrence of reflective cracks in asphalt concrete overlays; The panel layer 5 and the asphalt concrete overlay layer have good interlayer bonding force, which suppresses the generation and expansion of reflective cracks.

working principle:

The mechanism of action of the locally restrained steel bar 9: the stiffness of the locally restrained steel bar 9 is greater than that of the cement concrete, and a small vertical displacement difference is generated at the transverse joint 7 between the panels of the old cement panel 11, that is, the deflection difference between the panels. When the measured value of the deflection difference exceeds a certain limit (>0.04mm), the locally restrained steel bar 9 between the plates has the function of transmitting bending moment and shear force at the transverse joint 7 between the plates and the longitudinal joint 10 between the plates, improving the inter-plate Coordinated work ability helps reduce deformation and additional stress on board edges. The local restraint steel bars 9 connect the longitudinal front and rear adjacent plates together, so that the stress redistribution and coordinated deformation between the local restraint steel bars 9 between the plates and the old cement panel 11 are carried out, and the old cement panel layer 5 is paved with asphalt overlay. The overall shear capacity and overall tensile strength of the structure. The locally restrained steel bars 9 between the panels can be closely bonded to the old cement panel 11 in the horizontal plane to form a "bolt lock" effect, which can control the width of cracks at the transverse joint 7 between the panels of the old cement panel 11 and effectively restrain the gap between the panels. The crack propagates toward the upper asphalt concrete overlay, preventing reflective cracks from forming on the surface of the asphalt concrete overlay.

The locally restrained steel bars 9 pass through the continuous broken-line steel bars, so that the cracks connecting the horizontal joints 7 of the old cement panels 11 form a "network" from the isolated planted bars, and each planted bar can be evenly stressed, effectively ensuring that each planted bar All can exert its function of resisting the vertical displacement difference on both sides of the transverse joint 7 between the plates, that is, the deflection difference between the plates.

If the deflection difference between the boards is more than 0.06mm, the old board should be grouted to adjust the deflection difference between the boards to less than 0.06mm, so as to reduce the additional stress caused by the void at the bottom of the board.

The results of reflective crack disease research and finite element analysis show that reflective cracks appear near the edge area of the old cement panel (about 1/10 of the short side width of the old cement panel 11) under the action of traffic load, and the local restraint steel bar 9 is set in this area The anti-reflection crack performance of the pavement composite structure formed by adding the asphalt concrete overlay layer to the old cement panel layer 5 can be better enhanced.

Mechanism of multi-scale hybrid fiber reinforced epoxy asphalt macadam layer 4: Epoxy asphalt has good bonding and waterproof properties, etc., and can inhibit shear reflection cracks and water damage caused by traffic loads. Adding an appropriate amount of mixed fine fibers for crack resistance and coarse fibers for reinforcement with different diameters in the crushed stone helps to improve and enhance the interlayer shear and fracture performance of the multi-scale hybrid fiber-reinforced epoxy asphalt macadam layer 4 . The fine fiber used for crack resistance has higher elastic modulus and shorter length, and its own deformation is small under the action of tensile stress. , as the deformation continues to increase, most of the thin fibers are pulled out, and the contribution to the toughening in the large deformation stage is small. As the deformation of the specimen increases, the thick fiber and the matrix slip, and finally the thick polyolefin fiber is pulled out and broken. Due to the long thick fibers, more energy is consumed in the process of pulling out and breaking, which makes a great contribution to improving the toughness of the multi-scale hybrid fiber reinforced epoxy asphalt macadam seal layer 4 under large deformation. The good synergistic effect between fibers with different diameters and complementary advantages play a role in strengthening, toughening and crack resistance at different levels. Its strengthening and toughening mechanism can be described as "two lines of defense against cracking".

In addition, since the fine fibers for crack resistance are extremely fine, after being mixed with the thick polypropylene fibers for reinforcement, a "fiber chain" mechanism is formed with the thick fibers during the stirring process, making it more difficult for the fibers in the reflective cracks to be pulled out, which further plays an important role. Enhance toughening effect.

The above-described embodiments are only preferred embodiments of the present invention, and are not limitations to the technical solutions of the present invention. As long as they are technical solutions that can be realized on the basis of the above-mentioned embodiments without creative work, they should be regarded as falling into the scope of the patent of the present invention. within the scope of protection of rights.

Claims (9)

1. a kind of old concrete road surface inhibits the composite construction of reflection crack, including base, old cement panel layer and it is laid on water Asphalt Concrete Overlay on mud panel layer；The old cement panel layer includes several Geju City cement panel units；It is described old Cement panel unit includes the old cement panel of duplicate rows biserial setting；It is characterized in that：Further include being laid on old cement panel layer Multi-dimension mixing fibre enhancement epoxy bitumen macadam seal coat between Asphalt Concrete Overlay；The bituminous concrete overlays Layer includes middle grain formula bitumen concrete cutting optimal, modified emulsified asphalt adhesive layer and the asphalt-mastic-broken stone being laid with successively from bottom to up Upper layer；It is provided with transverse joint between plate between the old cement panel being laterally arranged, is set between longitudinally disposed old cement panel It is equipped with longitudinal seam between plate；By the way that longitudinal seam is connected between transverse joint and plate between plate between the old cement panel unit； It is carved with broken line connected in star on the old cement panel layer；The broken line connected in star is arranged between plate at transverse joint, and longitudinal direction is passed through Wear entire old cement panel layer；The fold-line-shaped local restriction reinforcing bar to match with it is provided in the broken line connected in star.

2. a kind of old concrete road surface as described in claim 1 inhibits the composite construction of reflection crack, it is characterised in that：It is described Fold-line-shaped local restriction reinforcing bar is the spiral of diameter 25-35mm；The fold-line-shaped local restriction steel-bar arrangement is trapezoidal wave Shape, including be separately positioned between plate at left and right sides of transverse joint, shape is consistent, and transverse joint side between trapezoidal bottom edge plate It is trapezoidal to what is uninterruptedly connected successively；The left and right sides transverse width of the fold-line-shaped local restriction reinforcing bar is 2*a+d⁰, wherein The d⁰The transverse joint width between cement plate, the ranging from 400-500mm of a；The fold-line-shaped local restriction steel bar ladder The outermost width of shape wave protrusion is 2*b+z⁰, wherein the z⁰The longitudinal seam width between plate, the ranging from 300- of the b 400mm；The width of the trapezoidal wave a cycle of the fold-line-shaped local restriction reinforcing bar is 3*c+b, wherein the c is ranging from 500-600 mm。

3. a kind of old concrete road surface as claimed in claim 1 or 2 inhibits the remodeling method of the composite construction of reflection crack, It is characterized in that：Include the following steps：

（1）Fold-line-shaped local restriction formed reinforcing steel bars：Spiral is selected, according to the width of transverse joint between the plate and the plate Between longitudinal seam width, spiral is bent into required fold-line-shaped, complete the fold-line-shaped local restriction reinforcing bar at Type；

（2）The flexure of old cement panel pre-processes：The old cement panel for needing seam to reinforce is measured into flexure difference andante, is chosen Select the old cement panel of flexure difference measured value≤0.06mm；

（3）Bar planting pre-processes：To the old cement panel of the flexure difference measured value≤0.06mm picked out, bar planting pretreatment is carried out, Vehicle Load additional stress concentrated area between the plate of old cement panel at transverse joint, i.e., transverse joint both sides between plate At 400-500mm ranges, trapezoidal groove, length, width and the angle of the broken line connected in star and fold-line-shaped office are cut into across seam Portion's constraint rebar sizes match, and the depth of broken line connected in star is 50-70mm, and broken line connected in star is set as bar planting position； It is purged using hair-dryer doubling linear groove；

（4）Bar planting and bar planting protective layer make：Local restriction reinforcing bar is implanted into broken line connected in star；Use the rubble being stirred Concrete fill is poured into remaining space between broken line connected in star inside and local restriction reinforcing bar；

（5）Spray bituminous epoxy：Bituminous epoxy is transported to construction site using special bituminous epoxy resupply vehicle and carries out bituminous epoxy Sprinkling, sprinkling is uniform, and the place not being sprayed onto carries out artificial mend and spills；

（6）Prepare the rubble of the fiber containing multi-dimension mixing：The basaltic broken stone of the grain sizes such as selection, resistance are split to be used with fine fibre and enhancing Crude fibre；Selected materials are subjected to dry mixing, are uniformly mixed with crude fibre with rubble with fine fibre and enhancing until will hinder to split；

（7）Dispense the rubble of the fiber containing multi-dimension mixing：Using truck spreader, on bituminous epoxy, uniformly dispense containing multiple dimensioned mixed The rubble of miscellaneous fiber；The step（5）, the step（6）With the step（7）Complete the multi-dimension mixing fiber reinforcement ring The laying of oxygen bitumen macadam seal coat；

（8）It is laid with cutting optimal：Grain formula bitumen concrete in selection is sprayed in the crushed stone sealing of multi-dimension mixing fibre enhancement epoxy pitch It is molded in -48h for 24 hours, grain formula bitumen concrete cutting optimal in laying；

（9）It is laid with adhesive layer：Modified emulsifying asphalt is selected, modified emulsified asphalt adhesive layer is laid on subsurface；

（10）It is laid with upper layer：Asphalt-mastic-broken stone is selected, asphalt-mastic-broken stone upper layer is laid on adhesive layer.

4. a kind of old concrete road surface as claimed in claim 3 inhibits the remodeling method of the composite construction of reflection crack, special Sign is：The step（2）After flexure difference measures between middle plate, the old cement panel of flexure difference measured value ＞ 0.06 is being walked Suddenly（3）Before, first carry out old cement panel grouting treatment；The grouting material of the grouting treatment selects cement mortar, cement mortar Proportioning be：1.0:5.

5. a kind of old concrete road surface as claimed in claim 3 inhibits the remodeling method of the composite construction of reflection crack, special Sign is：The step（5）The fountain height of middle sprinkling bituminous epoxy is 0.7-0.8kg/ ㎡, and the temperature of bituminous epoxy is 120 DEG C.

6. a kind of old concrete road surface as claimed in claim 3 inhibits the remodeling method of the composite construction of reflection crack, special Sign is：The step（6）In, the resistance, which is split, to be set as with fine fibre in vinal, polyacrylonitrile or polyester fiber It is one or more；A diameter of 0.02-0.04mm with fine fibre, length 6-12mm are split in the resistance, and fine fibre volume fraction is 2%-3%；The enhancing is provided in round section polypropylene monofilament with crude fibre；The coarse-fibred a diameter of 0.15- of the enhancing 0.30mm, length 10-20mm, density 0.91g/cm³, crude fibre volume fraction is 1%-2%；The rate of the dry mixing is 1200r/min, dry mixing time are 30s.

7. a kind of old concrete road surface as claimed in claim 3 inhibits the remodeling method of the composite construction of reflection crack, special Sign is：The step（6）In, the specification of selected basaltic broken stone is 4.75-9.5mm, dosage 6kg/m²；The step Suddenly（7）In, dispense the coverage rate ＞ 70% of the rubble of the fiber containing multi-dimension mixing.

8. a kind of old concrete road surface as claimed in claim 3 inhibits the remodeling method of the composite construction of reflection crack, special Sign is：The thickness of the multi-dimension mixing fibre enhancement epoxy bitumen macadam seal coat is 0.8cm；Under the middle grain formula bitumen concrete The middle grain formula bitumen concrete of face layer choosing AC-16C models, thickness 6cm；The asphalt-mastic-broken stone upper layer selects SMA-13 The asphalt-mastic-broken stone of model, thickness 4cm；During the modified emulsified asphalt adhesive layer is used to bond below grain formula bitumen concrete Layer and asphalt-mastic-broken stone upper layer.

9. a kind of old concrete road surface as claimed in claim 3 inhibits the remodeling method of the composite construction of reflection crack, special Sign is：The step（4）In, the strength grade of the crushed stone concrete filler is C20-C40.