Bridge floor base milling and polishing precision treatment construction method

Abstract

The invention relates to the technical field of bridge floor base treatment, in particular to a bridge floor base milling and polishing precision treatment construction method which comprises the following steps: preparation before construction; debugging the milling machine in place; carrying out milling operation; checking the milling quality; sweeping a bridge floor; and treating bridge floor defects. The bridge concrete pavement layer interface finish milling planer can thoroughly remove a laitance layer on a bridge tunnel structure interface, so that the concrete surface texture is uniform and fine, the roughness is enhanced, better technical indexes such as the exposed bone rate and the construction depth are achieved, and the interlayer bonding capacity of bridge deck cement concrete and asphalt concrete is enhanced. According to the method, the problem of miss-milling local areas caused by poor flatness of the bridge deck pavement layer can be solved by using sand blasting and shot blasting operation after finish milling, the advantage of high speed of finish milling is fully utilized, the characteristics of flexibility and convenience of small-area operation of a shot blasting machine are also played, and meanwhile, the characteristics of small interference of shot blasting operation, low cost and the like are reflected. And a protection effect is achieved on weak points of a concrete pavement surface.

Description

Technical Field

[0001] The invention relates to the technical field of bridge deck base treatment, in particular to a bridge deck base milling and polishing treatment construction method. Background Art

[0002] With the rapid development of my country's transportation industry, bridge engineering has become an important part of national infrastructure. As an important part of the bridge driving system, bridge deck pavement is an extension of the functional requirements of highway pavement on the bridge. Due to water damage and incomplete bridge base surface treatment, the bridge deck pavement of many bridges in my country has suffered different types of damage after opening to traffic. Some of them even suffered serious damage, cracking, potholes, bulges, slippage and other diseases in a very short time, which directly affected the normal use of the road surface. It not only hindered normal traffic and affected the beauty of the bridge deck, but also made it more likely to cause traffic accidents. At the same time, it also brought great difficulties to the maintenance of the bridge and increased the cost of the later maintenance and operation of the bridge. Summary of the invention

[0003] The purpose of the present invention is to provide a bridge deck base milling and polishing treatment construction method in view of the problems existing in the prior art.

[0004] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0005] The bridge deck base milling and polishing treatment construction method is characterized by comprising the following steps:

[0006] Step 1: Preparation before construction;

[0007] Step 2: Debug the milling machine in place;

[0008] Step 3: Milling operation;

[0009] Step 4: Milling quality inspection;

[0010] Step 5: Clean the bridge deck;

[0011] Step 6: Bridge deck defect treatment.

[0012] Preferably, in step 1, the pre-construction preparation includes the following steps:

[0013] Step (1), in order to prevent the occurrence of missed milling, before the bridge deck milling operation, a skid loader is first used to thoroughly clean the entire bridge deck, and pre-cleaning work is performed on the local protrusions on the cement concrete surface of the bridge deck or individual exposed steel bars, that is, the protruding blocks on the bridge deck and the exposed steel bars on the bridge deck are removed by manual chiseling, and an angle grinder or electric welder is used to remove them;

[0014] Step (2), then deal with the temporary expansion joints, and temporarily deal with the expansion joints with the solution of "square wood + geotextile filling + fine aggregate filling 10 cm away from the pavement surface + concrete backfill to the bridge pavement surface" to ensure the continuous operation of the milling machine;

[0015] Step (3), finally, the smoothness of the pre-cleaned bridge deck is tested, and the data is recorded in sections as a basis for determining the milling depth control during the fine milling of the section.

[0016] Preferably, in step 2, the in-situ debugging of the milling machine includes the following steps:

[0017] Step (1) Before starting the milling machine, first check the looseness of the screws and fasteners in various parts. If any looseness is found, tighten them. Check whether the steering system and brake system are flexible and reliable. Check whether there is any leakage in the hydraulic system and whether the hydraulic oil is sufficient. Check whether the milling drum tools are complete, intact and firmly installed. The milling drum safety cover should be well installed, complete and effective.

[0018] Step (2), make preparations and start the engine; when starting, put the throttle in a small or medium position, and gradually increase the throttle to the maximum position to work, let the engine idle and warm up at any time, check the display values ​​of each instrument and the engine operation status, and when the water temperature of the engine reaches 60°C, the milling machine can start and drive to the work site before working;

[0019] Step (3), before the operation, three indicators should be selected. First, the milling depth. Set the milling depth of 3-5mm on the milling machine operation panel to ensure that the bridge deck pavement layer is not damaged; second, the operating speed. Start slowly and smoothly. After the start is normal, control the speed to 8-12m. The milling machine operating speed can be adjusted according to the new and old milling machine cutter heads; third, the overlap width of the milling machine. To determine these three parameters, the exposure degree and surface roughness of the aggregate should be tested during the trial milling process. According to the test results, the parameters should be adjusted repeatedly to determine the above three key parameters for formal construction.

[0020] Preferably, in step three, the milling operation includes the following steps:

[0021] Step (1): Selection of milling machine model

[0022] Pre-select a large milling machine with a working width of 2m or more and equipped with a milling drum equipped with a fine milling cutter head, an operating speed of 10-15m / min, a vehicle-mounted vacuum sandblasting and shot blasting machine, a working width of 40cm, an operating speed of 8-12m / min, and a small hand-push milling machine, a milling width of 20cm, and a speed of 2.5m / min;

[0023] During the construction process, according to the specific characteristics of the project and construction needs, timely and reasonable equipment selection is carried out. The milling machine can work alone or in pairs. In order to ensure the flatness of the surface after milling and prevent defects such as misalignment or missed milling, the overlap length between the two construction work surfaces of the milling machine is 5-10 cm; the hand-push milling machine and vacuum shot blasting machine are used to fill the gaps that are not milled by the large milling machine during construction to ensure full coverage of the corners.

[0024] Step (2), milling and polishing operation, specifically comprises the following steps:

[0025] ① Main interface milling and polishing: A large milling machine with an operating width of not less than 2m is used, and a precision milling drum with more than 672 cutter heads is equipped, and an extended balance beam with automatic leveling is equipped. The machine is heavy, stable, and has a wide milling path. The whole section of the bridge deck is milled, and the overlap width of each milling is preferably 5-10cm to ensure the control of the transverse flatness. The precision milling heads and the precision milling drum can ensure the flatness and structural depth. The balance beam can ensure a large range of leveling and make secondary corrections to the flatness of the bridge deck.

[0026] ② After full-section milling with a large milling machine at a depth of 3-5 mm, some parts were missed due to poor control of the bridge deck flatness. A hand-pushed vacuum sandblasting and shot blasting machine was used for local polishing to ensure that the concrete pavement layer of the bridge deck was not damaged and the interlayer bonding strength was guaranteed;

[0027] ③ Edge milling: Due to the technological limitations of large-scale precision milling equipment, the edge of the bridge deck anti-collision guardrail and the guardrail base cannot be milled within 200mm. A small milling machine is used to mill the edge of 200mm to ensure the quality of the bridge deck side milling and the whole section is processed without dead angles;

[0028] ④ For the drainage holes on the bridge deck, a hand-push milling machine is used to perform multiple milling to form a 3-5mm height difference between the bridge pavement interface and the drainage holes on the bridge deck after the initial milling, forming a fan-shaped waterway outlet with an arc length of 42cm (60 degrees of central angle) and a radius of 40cm at each drainage hole, which effectively solves the problem of smooth drainage between layers;

[0029] ⑤ The waste generated during the milling process is transported to the waste dump by dump trucks for storage.

[0030] Preferably, in step 4, the milling quality inspection includes the following steps:

[0031] During the milling process of the bridge deck, the speed of the milling machine is strictly controlled, and a full-time quality inspector will track and observe the whole process. The milling effect is judged by visual inspection, GPS reference board and other methods until the surface slurry is completely removed to ensure that the construction requirements are met. The selection of construction parameters for bridge and tunnel surface milling is based on the premise of meeting the quality requirements of bridge deck treatment. If there are design requirements, they will be implemented according to the design. If there are no clear design requirements, they will be controlled according to the following indicators:

[0032] In order to further analyze the influence of bridge deck treatment methods on interlayer adhesion, a comparative test of asphalt layer-by-layer pull-out on-site was conducted to compare the test data of roughened bridge deck concrete, ordinary milled bridge deck, and finely treated bridge deck (fine milling with shot blasting machine and small milling machine).

[0033] After multiple test comparisons and summaries, the refined test data reached the following average indicators.

[0034] (1) The structural depth TD is less than 5 mm, measured by manual sand laying method;

[0035] (2) The aggregate exposure rate is visually greater than 70%, and generally should be able to reach more than 80%;

[0036] (3) The friction coefficient is greater than 50BPN;

[0037] (4) Surface roughness Rz, 50-100.

[0038] Preferably, in step five, after the bridge deck is milled, it is first cleaned with a skid loader, and a hair dryer or air compressor is used in conjunction with manual labor to completely remove the dust and waste left on the bridge deck; for sections that are difficult to clean, a high-pressure water gun is used to rinse them until they are completely clean.

[0039] Preferably, in step six, the bridge deck defect treatment includes: the defects exposed after the bridge deck is milled are mainly cracks on the concrete surface, including both obvious shrinkage cracks that appear after the construction is completed, and micro cracks caused by stress release on the concrete surface after the strength is formed. Such cracks are generally within 3-5mm on the concrete surface. Although they will not directly affect the use function of the bridge deck, they will damage the bridge deck pavement layer due to the intrusion of water, reducing the service life of the bridge deck pavement; the specific treatment method is to use a powerful hair dryer to remove the floating dust on the surface, and use a synchronous sealing vehicle to spray modified emulsified asphalt along the route direction (the spraying amount is 0.25L / m 2 ) and spread machine-made sand; then use a synchronous sealing vehicle to spray modified emulsified asphalt in the opposite direction of the route (spraying volume is 0.25L / m 2) and spread machine-made sand; apply the sprayed emulsified asphalt four times (two straight lines and two diagonal lines) at a time to "squeeze" the emulsified asphalt into the concrete cracks and repair the defects of the pavement base surface. After the emulsion is broken, the hot-melt SBS modified asphalt gravel seal is constructed as required, and finally a 3-5 mm thick waterproof layer is formed on the bridge deck.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The fine milling of the bridge concrete pavement interface of the present invention can completely remove the floating slurry layer at the interface of the bridge and tunnel structure, making the concrete surface texture uniform and fine, and enhancing the roughness, achieving better technical indicators such as exposed rate and structural depth, and enhancing the interlayer bonding ability of the bridge deck cement concrete and asphalt concrete.

[0042] 2. The present invention uses sandblasting and shot blasting after fine milling to solve the problem of local areas that are missed due to poor flatness of the bridge deck pavement layer. It fully utilizes the advantage of fast fine milling speed and the flexible and convenient small-area operation of the shot blasting machine. At the same time, it reflects that the shot blasting operation has little interference and protects the weak points of the concrete pavement surface.

[0043] 3. The present invention uses a hand-push small milling machine and a vacuum sandblasting and shot blasting machine to work together, which completely solves the problem that the 15-20cm area at the edge of the bridge deck anti-collision guardrail base and the edge of the anti-collision wall cannot be milled due to the limited working width of the milling equipment. The hand-push milling machine is used to perform multiple milling on the 3-5mm height difference formed between the bridge pavement interface and the bridge deck drainage hole after the initial milling, and a fan-shaped waterway outlet with an arc length of 42cm (60 degrees central angle) and a radius of 40cm is formed at each drainage hole, which effectively solves the problem of smooth drainage between layers; no dead angles are left on the bridge deck, which improves the integrity of the bridge deck pavement layer, effectively improves the shear resistance of the bridge deck pavement structure layer, and enhances the durability of the bridge deck.

[0044] 4. The present invention relies on the equipment's own transverse slope and longitudinal slope leveling instruments to synchronously correct the flatness of the bridge concrete pavement layer, which can better ensure the flatness and thickness of the asphalt surface layer while solving the long-standing problems of uneven thickness and "jumping" of the asphalt surface layer of bridges and tunnels.

[0045] 5. The process of the present invention is simple and easy to operate; it has a high degree of mechanization, is not dependent on the construction level of workers, and has high efficiency and fast speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of the construction method of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] The bridge deck base milling and polishing treatment construction method includes the following steps:

[0050] 1. Preparation before construction

[0051] In order to prevent the occurrence of missed milling and other phenomena, before the milling operation of the bridge deck, a skid loader is used to thoroughly clean the entire bridge deck, and pre-clean the local protrusions on the cement concrete surface of the bridge deck or individual exposed steel bars, that is, the protruding blocks on the bridge deck and the exposed steel bars on the bridge deck (the steel bars must not be bent and laid down) are removed by angle grinders or electric welders by manual chiseling. Temporary expansion joints are first handled, and the expansion joints are temporarily handled with the scheme of "square wood + geotextile filling + fine aggregate filling 10cm away from the pavement surface + concrete (asphalt mixture) backfilling to the bridge pavement surface" to ensure the continuous operation of the milling machine. The flatness of the pre-cleaned bridge deck is tested, and the data is recorded in sections as a basis for determining the milling depth control (3mm or 5mm) during the fine milling of this section.

[0052] 2. Milling machine in place and debugging

[0053] (1) Before starting the milling machine, first check the looseness of the screws and fasteners in various parts. If any looseness is found, tighten them. Check whether the steering system and braking system are flexible and reliable. Check whether there is any leakage in the hydraulic system and whether the hydraulic oil is sufficient. Check whether the milling drum tools are complete, intact and firmly installed. The milling drum safety cover should be well installed, complete and effective.

[0054] (2) Make preparations and start the engine. When starting, put the throttle in a small or medium position, and gradually increase the throttle to the maximum position to work. Keep the engine idling and warming up at any time, and check the display values ​​of each instrument and the engine operation. When the water temperature of the engine reaches 60℃, the milling machine can start and drive to the work site before working.

[0055] (3) Before the operation, three indicators should be selected. First, the milling depth. Set the milling depth of 3-5mm on the milling machine operation panel to ensure that the bridge deck pavement layer is not damaged. Second, the operating speed. Start slowly and smoothly. After the start is normal, the speed should be controlled at 8-12m. The milling machine speed can be adjusted according to the new and old milling machine heads. Third, the overlap width of the milling machine. To determine these three parameters, the degree of aggregate exposure and surface roughness should be tested during the trial milling process. According to the test results, the parameters are adjusted repeatedly to determine the above three key parameters for formal construction.

[0056] 3. Milling operation

[0057] (1) Selection of milling machine models

[0058] Pre-select a large milling machine with an operating width of 2m or more and equipped with a milling drum equipped with a fine milling cutter head, an operating speed of 10-15m / min, a vehicle-mounted vacuum sand blasting and shot blasting machine, an operating width of 40cm, an operating speed of 8-12m / min, and a small hand-push milling machine, a milling width of 20cm, and a speed of 2.5m / min.

[0059] During the construction process, equipment should be selected in a timely and reasonable manner according to the specific characteristics of the project and construction needs. Milling machines can work alone or in pairs. In order to ensure the flatness of the surface after milling and prevent defects such as misalignment or missed milling, the overlap length between the two construction surfaces of the milling machine is 5-10 cm. The hand-push milling machine and vacuum shot blasting machine will fill the gaps that are not milled by the large milling machine during construction to ensure full coverage of the corners.

[0060] (2) Milling and polishing

[0061] ① Main interface milling and polishing: Use a large milling machine with an operating width of no less than 2m, equipped with a precision milling drum with 672 (or more) cutter heads, and equipped with an extended balance beam for automatic leveling. Taking advantage of the heavy machine body, high stability, and wide milling path, milling is performed on the entire cross-section of the bridge deck. The overlap width of each milling is preferably 5-10cm to ensure the control of the lateral flatness; the use of multiple precision milling heads and precision milling drums can ensure flatness and structural depth; the use of a balance beam can ensure leveling over a large range and make secondary corrections to the flatness of the bridge deck.

[0062] ② After full-section milling with a large milling machine at a depth of 3-5 mm, some parts were missed due to poor control of the bridge deck flatness. A hand-push vacuum sandblasting shot blasting machine was used for local polishing to ensure that the concrete pavement layer of the bridge deck was not damaged and to ensure the interlayer adhesion.

[0063] ③ Edge milling: Due to the technological limitations of large-scale precision milling equipment, the bridge deck anti-collision guardrail and the edge of the guardrail base cannot be milled within 200mm.

[0064] A small milling machine is used to mill the edge of 200mm, thereby ensuring the quality of the milling of the bridge deck sides and processing the entire section without dead corners.

[0065] ④ For the drainage holes on the bridge deck, a hand-push milling machine is used to perform multiple milling to create a height difference of 3-5㎜ between the interface of the bridge pavement layer and the drainage holes on the bridge deck after the initial milling. A fan-shaped waterway outlet with an arc length of 42㎝ (central angle of 60 degrees) and a radius of 40㎝ is formed at each drainage hole, which effectively solves the problem of smooth drainage between layers.

[0066] ⑤ The waste generated during the milling process is transported to the waste dump by dump trucks for storage.

[0067] (3) Technical requirements for milling operations

[0068] ① When operating the milling machine, the clutch should be disengaged first, and then engaged after the milling machine is in gear.

[0069] ② When driving at first speed or parking, slowly lower the milling drum to the milling depth.

[0070] ③The maximum cutting depth of the concrete surface in one milling operation shall not exceed the specified value of the machine.

[0071] ④ It is strictly forbidden to use the milling machine at high speed to avoid damaging the cutter head.

[0072] ⑤ It is strictly forbidden to change gears during milling operations. The main oil pump control lever should be placed in the "neutral position" when changing gears.

[0073] ⑥ During the operation of the milling machine, attention should be paid to the working conditions of various indicator lights and instruments at any time. The operator must not leave the driving position, otherwise the milling drum must be lifted in advance.

[0074] 4. Milling quality inspection

[0075] During the milling process of the bridge deck, the speed of the milling machine is strictly controlled. Full-time quality inspectors will track and observe the whole process, and use visual inspection, GPS control board and other methods to judge the milling effect until the surface slurry is completely removed to ensure that the construction requirements are met. The selection of construction parameters for bridge and tunnel surface milling is based on the premise of meeting the quality requirements of bridge deck treatment. If there are design requirements, they will be implemented according to the design. If there are no clear design requirements, they will be controlled according to the following indicators:

[0076] In order to further analyze the influence of bridge deck treatment methods on interlayer adhesion, a comparative test of asphalt layer-by-layer pull-out on-site was conducted to compare the test data of roughened bridge deck concrete, ordinary milled bridge deck, and finely treated bridge deck (fine milling with shot blasting machine and small milling machine).

[0077] The pull-out test data and failure positions at different positions are shown in Table 1

[0078] Table 1 Pull-out test data and failure position

[0079]

[0080] After multiple test comparisons and summaries, the refined test data reached the following average indicators.

[0081] (1) The structural depth TD is less than 5 mm, measured by manual sand laying method;

[0082] (2) The aggregate exposure rate is visually greater than 70%, and generally should be able to reach more than 80%;

[0083] (3) The friction coefficient is greater than 50BPN;

[0084] (4) Surface roughness Rz, 50-100.

[0085] 5. Bridge surface cleaning

[0086] After milling, use a skid loader to clean first, and use a blower or air compressor to remove the dust and waste left on the bridge deck. For sections that are difficult to clean, use a high-pressure water gun to rinse until they are completely clean.

[0087] 6. Bridge Deck Defect Treatment

[0088] The defects exposed after the bridge deck was milled were mainly cracks on the concrete surface. There were obvious shrinkage cracks that appeared after the construction was completed, and micro cracks caused by stress release on the concrete surface after the strength was formed. These cracks were generally within 3-5mm on the concrete surface.

[0089] Although it will not directly affect the use of the bridge deck, the intrusion of water will damage the bridge deck pavement and reduce the service life of the bridge deck pavement. The specific treatment method is to use a strong hair dryer to remove the floating dust on the surface, and use a synchronous sealing vehicle to spray modified emulsified asphalt along the route (spraying amount is 0.25L / m 2 ) and spread machine-made sand; then use a synchronous sealing vehicle to spray modified emulsified asphalt in the opposite direction of the route (spraying volume is 0.25L / m 2 ) and spread machine-made sand. Apply the sprayed emulsified asphalt four times (two straight lines and two diagonal lines) at a time to "squeeze" the emulsified asphalt into the concrete cracks and repair the defects of the pavement base surface. After the emulsion is broken, the hot-melt SBS modified asphalt gravel seal is constructed as required, and finally a 3-5 mm thick waterproof layer is formed on the bridge deck.

[0090] Example 2: Benefit Analysis

[0091] 1. Social Benefits

[0092] The construction method of fine treatment of the bridge deck base surface ensures the bonding ability between the bridge deck cement concrete pavement and the asphalt mixture pavement, greatly prevents moisture from entering the bridge deck cement concrete layer, protects the steel bars in the pavement layer from rusting and the concrete from being damaged, thereby improving the overall quality and service life of the bridge. A comparison of several commonly used bridge deck treatment construction methods is shown in Table 2.

[0093] Table 2 Comparison of bridge deck treatment construction methods

[0094]

[0095]

[0096] From the analysis of Table 2, it can be seen that the fine milling construction process is simple, fast, easy to operate, and low in cost, but it cannot completely remove the floating slurry on the bridge deck. Although the quality of sandblasting is not affected by the flatness of the bridge deck itself, and the bridge surface after shot blasting has uniform roughness and good cleanliness, the interface layer is easily invalidated due to the small structural depth, shallow texture, and small structural depth formed on the interface surface. The bridge deck fine treatment construction technology (fine milling and matching shot blasting machine, small milling machine) can completely treat the bridge deck in all directions and without dead ends. The macroscopic structural depth of the interface formed is large, the interface edges are clearer, the groove depth is more uniform, the bridge surface is rough, the texture is uniform, and the treatment effect is good. Although the cost is relatively higher than that of fine milling and shot blasting, it is more scientific and reasonable than the other two construction technologies, and the existing defects are repaired more thoroughly, so that the waterproof performance of the bridge deck is guaranteed. The construction efficiency has been greatly improved, the service life has been extended, and the cost of later maintenance and repair has been reduced. The requirements of the national transportation industry for saving, low-carbon and sustainable development have been achieved, and it has good social benefits.

[0097] 2. Economic Benefits

[0098] 1. Comparison of construction period

[0099] Taking the fourth section of Weiwu road surface as an example, the project's bridge deck base surface treatment area is 341,000 square meters.

[0100] (1) Fine milling takes 71 days (calculated based on 8 hours of normal work per day)

[0101] (2) Shot blasting requires 355 days (calculated based on 8 hours of normal work per day)

[0102] (3) Fine milling combined with shot blasting: From February 25, 2019 to March 1, 2019, the milling drum of the milling machine was upgraded to a fine milling drum. Construction began on March 2, 2019, and the milling was basically completed on May 10, 2019. The shot blasting machine entered the site and started construction on April 18, 2019. By May 21, 2019, 280,000 square meters had been completed. According to the actual construction time of Weiwu pavement, it was 81 days (rainy days and abnormal construction obstacles were not counted).

[0103] 2. Cost comparison

[0104] Table 3 Comparison of costs of bridge deck treatment construction methods

[0105] project Fine milling Vacuum shot blasting Fine milling and shot blasting Construction efficiency About 600㎡ / h About 120㎡ / h About 500㎡ / h Cost Comparison 5 yuan / m2 10 yuan / m2 6 yuan / m2

[0106] Embodiment 3, application example

[0107] 1. Application Example 1

[0108] 1.1 Project Name: Shiyan to Tianshui National Highway Gansu Section Huixian (Dashibei) to Tianshui Highway Pavement Project STLM03 Contract Section

[0109] 1.2 Project location: Xihe County, Longnan City, Gansu Province

[0110] 1.3 Project Overview: The starting pile number of the contract section is K625+100, the end pile number is K653+915.955, and the total length of the route is 28.813 km. One bridge is 132.6 m long, four middle bridges are 210 m long, a separated overpass is 806 m long, and a shot blasted bridge deck is 230,332 m long. 2 .

[0111] 1.4 Construction start and completion dates: Construction started on April 16, 2014, and passed the acceptance inspection on September 23, 2015.

[0112] 2. Application Example 2

[0113] 2.1 Project Name: Lanzhou to Haikou National Expressway Weiyuan to Wudu Section Pavement Engineering Fourth Contract Section

[0114] 2.2 Project location: Dangchang County, Longnan City, Gansu Province

[0115] 2.3 Project Overview: The total length of the contract section is 31.91 km. There are 14 large bridges, 19 medium bridges, 1 flyover, and 341,310 m of shot blasted bridge deck. 2 .

[0116] 2.4 Construction start date: Construction started on October 20, 2017, and the project was completed, accepted and opened to traffic on December 25, 2019.

[0117] 3. Application effect

[0118] This method has been applied in the third standard of Shitian pavement and the fourth standard of Weiwu pavement. Since its use, the bridge deck has no displacement, no rutting, and no damage, and the effect is good. The bridge deck base surface fine treatment construction method ensures the quality of bridge deck pavement construction, improves the durability of the bridge deck pavement layer, extends the service life of the bridge, reduces the later maintenance costs of the bridge, and improves the safety and comfort of vehicles driving on the bridge. The bridge deck base surface fine treatment construction method has a high degree of mechanization, simple and easy equipment to operate and promote, and has little dependence on the technical level of workers. It has positive significance for the development of engineering equipment and the promotion and application of the "four new technologies". The environmental benefits, economic benefits and social benefits are significant, and it is of great promotion value.

[0119] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. The bridge deck base milling and polishing treatment construction method is characterized by: The steps include: Step 1: Preparation before construction; Step 2: Debug the milling machine in place; Step 3: Milling operation; Step 4: Milling quality inspection; Step 5: Clean the bridge deck; Step 6: Bridge deck defect treatment.

2. The bridge deck base milling and polishing construction method according to claim 1 is characterized in that: In step 1, the pre-construction preparation includes the following steps: Step (1), in order to prevent the occurrence of missed milling, before the bridge deck milling operation, a skid loader is first used to thoroughly clean the entire bridge deck, and pre-cleaning work is performed on the local protrusions on the cement concrete surface of the bridge deck or individual exposed steel bars, that is, the protruding blocks on the bridge deck and the exposed steel bars on the bridge deck are removed by manual chiseling, and an angle grinder or electric welder is used to remove them; Step (2), then deal with the temporary expansion joints, and temporarily deal with the expansion joints with the solution of "square wood + geotextile filling + fine aggregate filling 10 cm away from the pavement surface + concrete backfill to the bridge pavement surface" to ensure the continuous operation of the milling machine; Step (3), finally, the smoothness of the pre-cleaned bridge deck is tested, and the data is recorded in sections as a basis for determining the milling depth control during the fine milling of the section.

3. The bridge deck base milling and polishing construction method according to claim 1 is characterized in that: In step 2, the in-situ debugging of the milling machine includes the following steps: Step (1) Before starting the milling machine, first check the looseness of the screws and fasteners in various parts. If any looseness is found, tighten them. Check whether the steering system and brake system are flexible and reliable. Check whether there is any leakage in the hydraulic system and whether the hydraulic oil is sufficient. Check whether the milling drum tools are complete, intact and firmly installed. The milling drum safety cover should be well installed, complete and effective. Step (2), make preparations and start the engine; when starting, put the throttle in a small or medium position, and gradually increase the throttle to the maximum position to work, let the engine idle and warm up at any time, check the display values ​​of each instrument and the engine operation status, and when the water temperature of the engine reaches 60°C, the milling machine can start and drive to the work site before working; Step (3), before the operation, three indicators should be selected: first, the milling depth. Set the milling depth of 3-5mm on the milling machine operation panel to ensure that the bridge deck pavement is not damaged; second, the operating speed. Start slowly and smoothly. After the start is normal, control the speed to 8-12m. The milling machine operating speed can be adjusted according to the new and old milling machine cutter heads; Third, the overlap width of the milling machine. To determine these three parameters, the degree of aggregate exposure and surface roughness must be tested during the trial milling process. Based on the test results, the parameters must be adjusted repeatedly to determine the above three key parameters for formal construction.

4. The bridge deck base milling and polishing construction method according to claim 1 is characterized in that: In step three, the milling operation includes the following steps: Step (1): Selection of milling machine model Pre-select a large milling machine with a working width of 2m or more and equipped with a milling drum equipped with a fine milling cutter head, an operating speed of 10-15m / min, a vehicle-mounted vacuum sandblasting and shot blasting machine, a working width of 40cm, an operating speed of 8-12m / min, and a small hand-push milling machine, a milling width of 20cm, and a speed of 2.5m / min; During the construction process, according to the specific characteristics of the project and construction needs, timely and reasonable equipment selection is carried out. The milling machine can work alone or in pairs. In order to ensure the flatness of the surface after milling and prevent defects such as misalignment or missed milling, the overlap length between the two construction work surfaces of the milling machine is 5-10 cm; the hand-push milling machine and vacuum shot blasting machine are used to fill the gaps that are not milled by the large milling machine during construction to ensure full coverage of the corners. Step (2), milling and polishing operation, specifically comprises the following steps: ① Main interface milling and polishing: A large milling machine with an operating width of not less than 2m is used, and a precision milling drum with more than 672 cutter heads is equipped, and an extended balance beam with automatic leveling is equipped. The machine is heavy, stable, and has a wide milling path. The whole section of the bridge deck is milled, and the overlap width of each milling is preferably 5-10cm to ensure the control of the transverse flatness. The precision milling heads and the precision milling drum can ensure the flatness and structural depth. The balance beam can ensure a large range of leveling and make secondary corrections to the flatness of the bridge deck. ② After full-section milling with a large milling machine at a depth of 3-5 mm, some parts were missed due to poor control of the bridge deck flatness. A hand-pushed vacuum sandblasting and shot blasting machine was used for local polishing to ensure that the concrete pavement layer of the bridge deck was not damaged and the interlayer bonding strength was guaranteed; ③ Edge milling: Due to the technological limitations of large-scale precision milling equipment, the edge of the bridge deck anti-collision guardrail and the guardrail base cannot be milled within 200mm. A small milling machine is used to mill the edge of 200mm to ensure the quality of the bridge deck side milling and the whole section is processed without dead angles; ④ For the drainage holes on the bridge deck, a hand-push milling machine is used to perform multiple milling to form a 3-5mm height difference between the bridge pavement interface and the drainage holes on the bridge deck after the initial milling, forming a fan-shaped waterway outlet with an arc length of 42cm (60 degrees of central angle) and a radius of 40cm at each drainage hole, which effectively solves the problem of smooth drainage between layers; ⑤ The waste generated during the milling process is transported to the waste dump by dump trucks for storage.

5. The bridge deck base milling and polishing construction method according to claim 1 is characterized in that: In step 4, the milling quality inspection includes the following steps: During the bridge deck milling process, the speed of the milling machine is strictly controlled, and full-time quality inspectors track and observe the whole process. Visual inspection, GPS control board and other methods are used to judge the milling effect until the surface slurry is completely removed to ensure that the construction requirements are met. The selection of bridge and tunnel surface milling construction parameters is based on the premise of meeting the bridge deck treatment quality requirements. The design requirements are implemented according to the design. If the design does not have clear requirements, the following indicators are used for control: In order to further analyze the impact of bridge deck treatment methods on interlayer adhesion, through on-site asphalt layer-by-layer pull-out comparison tests, test data comparisons were made for the roughened bridge deck concrete, the ordinary milled bridge deck, and the finely treated bridge deck.

6. The bridge deck base milling and polishing construction method according to claim 5 is characterized in that: After multiple test comparisons and summaries, the processed test data averagely reached the following indicators: (1) The structural depth TD is less than 5 mm, measured by manual sand laying method; (2) The aggregate exposure rate is visually greater than 70% and can reach more than 80%; (3) The friction coefficient is greater than 50BPN; (4) Surface roughness Rz, 50-100.

7. The bridge deck base milling and polishing construction method according to claim 1 is characterized in that: In step five, after the bridge deck is milled, it is first cleaned with a skid loader, and a blower or air compressor is used in conjunction with manual labor to completely remove the dust and waste left on the bridge deck; for sections that are difficult to clean, a high-pressure water gun is used to rinse until they are completely clean.

8. The bridge deck base milling and polishing construction method according to claim 1 is characterized in that: In step six, the bridge deck defect treatment includes: the defects exposed after the bridge deck is milled are mainly cracks on the concrete surface, including both obvious shrinkage cracks that appear after the construction is completed, and micro cracks caused by the release of stress on the concrete surface after the strength is formed. Such cracks are generally within the range of 3-5mm on the concrete surface. Although they will not directly affect the use function of the bridge deck, they will damage the bridge deck pavement layer due to the intrusion of water, reducing the service life of the bridge deck pavement; the specific treatment method is to use a powerful hair dryer to remove the dust on the surface, and use a synchronous sealing vehicle to spray modified emulsified asphalt along the route direction, with a spraying amount of 0.25L / m 2 , and spread machine-made sand; then use a synchronous sealing vehicle to spray modified emulsified asphalt in the opposite direction of the route, with a spreading amount of 0.25L / m 2 , and spread machine-made sand; apply the sprayed emulsified asphalt four times at a time, twice in a straight line and twice in a diagonal line, "squeeze" the emulsified asphalt into the concrete cracks, repair and renovate the defects of the pavement base surface, and after demulsification, carry out the construction of hot-melt SBS modified asphalt gravel seal as required, and finally form a 3-5 mm thick waterproof layer on the bridge deck.

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