CONSTRUCTION PROCESS FOR QUICKLY AND INTEGRALLY REPLACING DAMAGED PAVEMENT SLAB WITHOUT SUSPENDING FLIGHTS OF CIVIL AVIATION

Abstract

A construction process for quickly and integrally replacing a damaged pavement slab without suspending flights of civil aviation is provided according to embodiments of the present application, including: a first stage: reinforcing a foundation of a damaged pavement slab by grouting; and a second stage: integrally replacing the damaged slab with early-strength and quick-drying concrete. The construction process of fast overall replacement of a damaged pavement slab in civil aviation non-suspend construction provided by the embodiments of the present application solves the limitations of the traditional pavement slab repair process well. The present application first reinforces the damaged pavement slab foundation through grouting construction to solve the problems of slab bottom vacancy, foundation settlement, and insufficient bearing capacity of the base layer; then uses the early-strength rapid-curing concrete suitable for rapid overall slab replacement of the pavement to carry out overall replacement construction for the damaged pavement slab.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of international application of PCT application No. PCT/CN2021/105043 filed on Jul. 7, 2021, which claims the priority benefit of China application No. 202110052087.7 filed on Jan. 15, 2021. The entirety of the above-mentioned patent applications is incorporated herein by reference and made a part of this specification.

TECHNICAL FIELD

The present application relates to the technical field of airport runway construction, in particular to a construction process of fast overall replacement of a damaged pavement slab in civil aviation non-suspend construction.

DESCRIPTION OF RELATED ART

With the rapid development of the domestic aviation industry and the updating of models, the traffic volume and the passenger flow volume are greatly increased, the operation pressure of a hub airport is gradually increased, and many airport runways which has not reached the design life has shown varying degrees of damage. In addition, in recent years, a considerable portion of airport runways have come to the design life, concrete pavement slabs are void, and the stress pattern changes. These hidden dangers not only influence normal transportation, but also directly threaten flight safety. Therefore, maintenance and repair of airport pavement for some time in the future has become an important task in airport field work.

The runway is the main place for aircraft to take off and land. Due to a slow growth of the strength of ordinary cement concrete, the use of ordinary cement concrete to stop the runway for maintenance needs to wait until the concrete coagulation strength has increased to the design strength (usually 28 days) before the traffic can be opened, which has a greater impact on the airport operation. Therefore, damaged pavement slabs of the airport runway are often repaired by non-suspend construction, that is, the flight area is temporarily closed for a few hours in the early morning of the night, and the damaged area is quickly repaired with rapid-curing high-strength repair materials, and the open traffic condition can be achieved through short maintenance after the repairing is finished.

Non-suspend construction has extremely high requirements on the performance of pavement repair materials and construction process. In the past, the treatment of damaged slabs was mainly to use epoxy resin mortar to partially repair damaged slabs. This repairing method has certain limitations: 1. Only the damaged surface layer is repaired, while the base layer below the damaged surface layer is not treated. That is, the symptoms are addressed instead of the cause. 2. Large shrinkage can easily lead to the formation of disadvantages such as joints and dislocations between the repaired area and the slab. 3. Due to the difference in strength between the repaired area and adjacent slabs, the damage of the repaired area and the adjacent slabs will be accelerated. 4. Normal temperature epoxy resin curing agents are generally toxic and have a greater impact on construction personnel and the environment. 5. When the temperature is low, the epoxy resin mortar will harden, and needs to be heated with a torch during the construction process, which leads to the construction cumbersome and dangerous. 6. The durability is poor, and it is easy to aging and peeling after exposure to sunlight and rain, which will affect the safety of airport operation.

SUMMARY

Embodiment of the present application provides a construction process for quickly and integrally replacing a damaged pavement slab without suspending flights of civil aviation, which well solves the limitations of the traditional pavement slab repairing process in engineering practice.

In order to achieve the above objective, the present application adopts the following technical solutions.

A construction process for quickly and integrally replacing a damaged pavement slab without suspending flights of civil aviation includes:

• a first stage: reinforcing a foundation of a damaged pavement slab by grouting; and
• a second stage: integrally replacing the damaged slab with early-strength and quick-drying concrete.

Preferably, the first stage includes:

• (1) positioning of a slab to be grouted: positioning and marking the damaged slab and adjacent slabs thereof;
• (2) positioning of grout holes: arranging the grout holes according to an effective diffusion radius of slurry, and shape and size of the pavement slab;
• (3) drilling and blowing holes: drilling holes on the pavement to penetrate a base layer into a soil subgrade, and blowing the holes to clean dust in the holes after the drilling is completed, wherein the grouting is performed after the blowing is completed;
• (4) preparing of slurry: preparing slurry while positioning the grout holes in the site;
• (5) grouting: grouting the slurry into the grout holes;
• (6) pressure relief and sealing holes: after the grouting is completed, pulling out a grouting tube when a grouting pressure is dissipated; and after the grouting tube is pulled out, sealing the holes with a quick-drying cement mortar;
• (7) testing of grouting effect: performing HWD deflection test on the grouted reinforcement area 28 days later after the grouting is completed, to determine whether slab edge deflection/slab interior deflection<2 and slab corner deflection/slab interior deflection<3, which indicate a good status of the foundation, and if yes, performing a next stage of replacement construction; and if not, performing the above steps (1) to (6) until the test results meet the above requirements.

Preferably, the second phase includes:

• (1) selecting of quick-drying concrete and performing of performance test: selecting a slab replacement material and performing laboratory mixing test to the selected material before construction in the site, and performing construction on a test section in the site to detect and familiarize with construction performance of the selected material;
• (2) preparing of material and calibrating of a concrete mixing vehicle: before construction in the site, loading materials required for construction into corresponding silos of a concrete mixing vehicle and weighing the concrete mixing vehicle, wherein the concrete mixing vehicle has an integrated function of mixing, transporting and pouring; calibrating a metering equipment of the concrete mixing vehicle after the loading is completed, mixing a small amount of concrete for test, and determining a construction mixture ratio for the current day according to state of the concrete;
• (3) entering site and positioning of slab to be replaced: determining a position where a slab is required to be quickly replaced according to design requirements;
• (4) construction preparation before breaking of the slab: before breaking the slab, removing navigation aid lamps on the damaged slab, laying geotextiles on adjacent slabs, and manually trimming out edges of the damaged slab along joints of the damaged slab with an electric pick;
• (5) breaking of the slab with a breaker: using breaking the damaged slab with a breaker from middle position of the slab, taking out the broken concrete blocks after the middle portion of the slab is broken, and breaking the slab toward the slab edge in turn, wherein the slab edge of the damaged slab is reserved for manual breaking;
• (6) removing concrete blocks and manual cleaning: after the breaking of the damaged slab is completed, removing concrete blocks, and manually clearing up fragments at the bottom of base layer until a dense and flat base layer is obtained;
• (7) Laying of geotextiles and wetting the bottom by sprinkling: after the cleaning, laying the geotextiles, and wetting the bottom by sprinkling the water;
• (8) pouring a first layer of concrete with the concrete mixing vehicle in place;
• (9) laying steel meshes: after pouring of the first layer of concrete is completed, installing steel meshes for reinforcement;
• (10) pouring a second layer of concrete: after the installation of the reinforcement steel meshes is completed, immediately pouring a second layer of concrete in a sequence from one side of the slab to the other, and during pouring, performing processes of leveling and mud extracting on concrete surface with a double steel tube vibrating beam;
• (11) exact leveling and surface finishing: after the processes of leveling and mud extracting with the double steel tube vibrating beam is completed, scraping the concrete surface with an aluminum alloy scraper, wherein cement slurry at the slab edge of adjacent slabs is cleaned up before the scraping, and during scraping, the bug holes are filled with concrete aggregate and excessive material are shoveled away with a shovel; and performing surface finishing after the scraping;
• (12) Curing: carrying out a process of a water spray curing;
• (13) slitting and grooving: performing processes of slitting and grooving according to performance of the quick-drying concrete used; and
• (14) sealing crack and recovering maker lines.

Preferably, in drilling and blowing holes, a drill bit of a drilling rig used for drilling holes on the pavement is not greater than 60 mm; the drilling holes penetrates the base layer into the soil subgrade by 10 cm; after reaching a design depth, an air compressor is used to blow the holes, and the blowing time is not less than 10 s.

Preferably, technical indicators to be controlled during the grouting process include: 1. grouting pressure: when grouting on airport pavement, a grouting pressure is not greater than 1.0 MPa; when the grouting pressure is maintained at a certain value and the amount of grouting is no longer increased during the grouting, the grouting is stopped; 2. slab surface elevation: an allowable elevation of the pavement slab during the grouting is no more than 5 mm, a final allowable elevation of the pavement slab after stabilization is not greater than 3 mm, and when the slab elevation is greater than 5 mm, the grouting is stopped; and 3. slurry overflowing situation around the slab: the grouting is stopped when a large of slurry overflows around the pavement slab during the grouting, and the overflowing slurry is cleaned up in time.

Preferably, in the construction preparation before breaking of the slab, manually trimming out, by using an electric pick, a protective layer with a width of not less than 15 cm and a depth of not less than 10 cm along joint of the damaged slab to prevent damage to adjacent slabs when the slab is broken by a large machine.

Preferably, in the breaking of the slab with a breaker, a region with width of 15 cm at the slab edge of the damaged slab is reserved for manual breaking.

Preferably, when the thickness of a concrete slab is 40 cm, pouring thickness of the first layer is 15 cm, and the thickness of the second layer is 25 cm; the pouring of the second layer of concrete is completed before initial setting of the first layer of concrete to prevent cold joints.

Preferably, in pouring of concrete on two adjacent slabs at the same time, in order to prevent formation of a cold joint between the two layers when the two slabs are simultaneously poured in a layered manner, arranging a half-height molding board in middle of gap between the two adjacent slabs, wherein height of the half-height molding board is ½ of thickness of a slab; pouring concrete on the two adjacent slabs in a layered manner separately, wherein a sequence for pouring is: erecting the half-height molding board→pouring a first layer of a first slab→pouring a second layer of the first slab→removing the half-height molding board→pouring a first layer of a second slab→pouring a second layer of the second slab.

Preferably, the water spray curing comprises: when hands cannot press into concrete surface and the concrete surface starts to heat up, performing the curing by sprinkling water with a sprayer, wherein a nozzle of the sprayer faces upwards during the early of the curing so that water mist fall on the concrete surface; it is ensure that the concrete surface is moist during the curing and the curing time is not less than 3 hours.

It can be seen from the technical solutions provided in the above embodiments of the present application that the construction process of fast overall replacement of a damaged pavement slab in civil aviation non-suspend construction provided by the embodiments of the present application has the following advantages.

• (1) scope of application of the process: the present application adopts a two-stage construction. The first stage is to reinforce a foundation of a pavement through a grouting method. This process technology is simple without a large mechanical equipment. It is convenient to enter and exit the field, the construction speed is fast, and it does not affect the flight safety of the pavement. It does not destroy the existing structural layer of the pavement, but also can effectively solve the problem of voiding at the bottom of the pavement slab, and can improve the density, strength and ground reaction modulus of the foundation. The second stage uses a quick-drying and early-strength concrete to quickly and integrally replace the damaged slab. Through the application of the new equipment of the concrete intelligent all-in-one vehicle and the improvement of concrete construction process of the traditional pavement, the construction time has been greatly shortened and the investment of equipment and personnel has been reduced. This process is very suitable for projects with limited space or projects that are not suitable for investing a large amount of machinery due to other reasons but with high engineering quality requirements and tight schedules, especially suitable for airport non-suspend construction;
• (2) In terms of equipment efficiency: the process personnel and equipment have a clear division of labor, and the construction process is arranged compactly. Especially when the foundation reinforcement or replacement construction are performed on multiple slabs, various construction equipment forms a benign cycle state, which effectively reduces the idle rate of equipment and increases the utilization;
• (3) In terms of construction quality: reinforcing the foundation of the pavement by the grouting method can effectively improve the bearing capacity of the foundation of the pavement, thereby improving the durability of the pavement slab. The optimization and improvement of the ordinary pavement concrete construction process ensures the construction quality of the concrete, and at the same time the adoption of the quick-drying and early-strength concrete can meet the intensity requirements of open traffic in a very short time;
• (4) In terms of construction progress: this process can effectively resolve the contradiction between construction schedule and construction quality, and accelerate the progress of the project;
• (5) In terms of engineering cost: the process uses the concrete intelligent all-in-one vehicle to complete the concrete mixing work with only 2 people, which not only improves the mixing quality, but also greatly reduces the labor and the investment of transportation machinery and equipment, effectively saving the cost.

The additional aspects and advantages of the present application will be partly given in the following description, which will become apparent from the following description, or learned through the practice of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to explain the technical solutions of the embodiments of the present application more clearly, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative work, other drawings can be obtained based on these drawings.

FIG. 1 is a schematic flow diagram of a construction process for quickly and integrally replacing a damaged pavement slab without suspending flights of civil aviation according to an embodiment of the present application;

FIG. 2 is a schematic flow diagram of a process (first stage) of reinforcing a foundation of a damaged pavement slab by grouting construction according to an embodiment of the present application;

FIG. 3 is a schematic layout diagram of grouting holes according to an embodiment of the present application;

FIG. 4 is a schematic flow diagram of a process (second stage) of integrally replacing a damaged pavement slab with the early-strength and quick-drying concrete according to an embodiment of the present application.

DESCRIPTION OF THE EMBODIMENTS

The following describes the implementation of the present application in detail. Examples of the implementation are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions. The following reference is made to the accompanying drawings. The described implementation is exemplary, and is only used to explain the present application, but cannot be interpreted as a restriction on the present application.

Those skilled in the art can understand that, unless specifically stated, the singular forms “a”, “an”, “the” and “this” used herein may also include plural forms. It should be further understood that the term “comprising” used in the description of the present application refers to the presence of the described features, integers, steps, operations, elements, and/or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or the combination thereof. It should be understood that when we say that an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the “connected” or “coupled” used herein may include wireless connection or coupling. The term “and/or” as used herein includes any unit and all combinations of one or more associated listed items.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as the general understanding of the ordinary skilled in the art to which the present application belongs. It should also be understood that, terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and unless defined as here, they will not be interpreted with idealized or overly formal meanings.

In order to facilitate the understanding of the embodiments of the present application, several specific embodiments will be used as examples for further explanation and description in conjunction with the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present application.

As shown in FIG. 1, a construction process for quickly and integrally replacing damaged pavement slab without suspending flights of civil aviation according to an embodiment of the present application includes the following steps.

In a first stage, a foundation of the damaged pavement slab is reinforced by grouting. In the first stage, a layout surveying is performed to position grout holes, and then the holes are drilled and meanwhile the grouting liquid is prepared. The drilling depth is required to be able to penetrate into the soil subgrade. After the above operations are completed, a grouting construction will be performed. The grouting construction is performed until the grouting pressure or the slab elevation reaches a critical value. After stopping the grouting, a grouting tube is pulled out after the grouting pressure is dissipated, and then the holes are sealed with a quick-drying mortar. After the grouting fluid reaches a design time, a HWD deflection test is performed on the grouted area to test a grouting effect. If the foundation bearing capacity meets the specification requirements, a next stage of replacement construction can be performed.

In a second stage, the damaged slab is replaced integrally with an early-strength and quick-drying concrete, which includes: breaking and removing positioning of the slab, laying geotextiles on the adjacent slabs, removing lamps, manually trimming the edge with an electric pick, breaking the slab from the middle position with a breaker in place, transporting concrete blocks, manually cleaning the edge and bottom with an electric pick, checking and accepting the base layer, laying geotextiles, wetting the base layer by sprinkling water, putting the concrete mixing vehicle in place and starting concrete pouring construction for two layers, in which a reinforced mesh is laid for reinforcement after pouring a first layer of concrete and then pouring a second layer of concrete; then performing operations of leveling and extracting by a vibrating beam of double steel tube, surface troweling, maintenance, joint-cutting and grooving and the like in order. The process of expanding and filling joints and recovery of the maker line is to be performed on the next day in the site.

The two-stage construction process is specifically described as follows.

• As shown in FIG. 2, in the first stage, the foundation of the replacement area is reinforced by grouting.
• (1) Positioning of slabs to be grouted
• In order to ensure the quality of the replacement process, not only the slab foundation of the replacement area is reinforced by grouting, but also the foundation of a slab adjacent to the replacement area is also reinforced by grouting. Before starting the grouting process, the slabs to be grouted shall be positioned and marked.
• (2) Positioning of grout holes
• Under the premise of ensuring the construction effect and uniformity, the layout of grout holes should take the following two important factors into account. The first factor is an effective diffusion radius of the slurry. For a foundation with larger gaps, the effective diffusion radius of the slurry is generally 1.5 m. The second factor is a shape and a size of the concrete pavement slab. It should be ensured that each part of the slab is stressed uniformly as much as possible. According to the shape and the size of the pavement slab, the layout of grout holes is shown in FIG. 3.
• (3) Drilling and blowing holes
• A suitable drilling rig should be used for drilling on the pavement with a drill bit not greater than 60 mm for example. The drilling depth is required to be able to penetrate the base layer to 10cm into the soil subgrade. Taking a second runway of Chongqing Jiangbei Airport as an example, the drilling hole depth=40 cm of pavement slab+36 cm of cement stabilized gravel+10 cm of the soil subgrade=86 cm. After drilling to a design depth, an air compressor should be used to blow the hole. The blowing time should not be less than 10 s to ensure that the dust in the holes should be blown out. The grouting should be carried out after the blowing process is completed.
• (4) Preparing of slurry
• The preparing of slurry should be carried out while positioning the holes in the site. The construction mix ratio is measured in strict accordance with the design requirements, and operations of adding and feeding materials are carried out according to the procedures to ensure the timely preparation and supply of the slurry. The proportion of the cement slurry should be detected in time with a slurry specific gravity detection recorder.
• (5) Grouting
• A grouting gun is inserted into the formed grout hole of the pavement slab to an appropriate depth, a seal rubber ring of the grouting gun is tighten, and a grouting pump is activated for slurry injection. The grouting amount is carefully recorded with a grouting automatic recorder. To ensure the quality of grouting and the flatness of the pavement, there are three main technical indicators to be controlled in the grouting process. 1. Grouting pressure: when grouting the airport pavement, a grouting pressure should be not greater than 1.0 MPa, preferably 0.3 Mpa-0.5 Mpa. When the grouting pressure is maintained at a certain value and the amount of grouting is no longer increased during the grouting, the grouting may be stopped. 2. Slab surface elevation: the allowable elevation of the pavement slab during the grouting is generally required to be no more than 5 mm, the final allowable elevation of the pavement slab after stabilization is required to be no greater than 3 mm, and when the slab elevation (elevation of non-settlement plate) is greater than 5 mm, the grouting should be stopped. 3. Slurry overflowing situation around the slab: the grouting should be stopped when a large of slurry overflows around the pavement slab during the grouting, and the overflowing slurry should be cleaned up in time.
• (6) Pressure relief and sealing holes
• After the grouting is completed, the grouting tube should not be pulled out immediately to prevent the slurry from leaking. With letting stand for 5-10 minutes or installing a pressure relief valve on the grouting tube, the grouting tube can be pulled out after the grouting pressure is relieved. After pulling out the grouting tube, the holes are sealed with a quick-drying cement mortar.
• (7) Testing of grouting effect
• HWD deflection test is performed on the grouted reinforcement area 28 days later after the grouting is completed. The situations of void beneath slab edge and void beneath slab corner are determined based on a ratio of “slab edge/slab interior” and “slab corner/slab interior” deflection, and the criterion follows the technical standards recommended in the “Technical Specifications for the Evaluation and Management of Civil Airport Pavements”. That is, “slab edge deflection/slab interior deflection<2” and “slab corner deflection/slab interior deflection<3” indicate a good status of the foundation, and then a next stage of replacement construction can be performed; and if the above requirements are not met, the above steps (1) to (6) are performed until the test results meet the requirements.

As shown in FIG. 4, the second stage in which the damaged slab is quickly replaced will be described below.

• (1) Selecting of quick-drying concrete and performing of performance test
• The present application mainly aims at the replacing of the damaged pavement slabs without suspending flights. Short construction time and high-quality requirements are the most important characteristics of non-suspend construction. Therefore, before construction in the site, it is necessary to carefully select the replacement materials, and a laboratory test of mixing is performed on the selected materials and on-site construction is carried out on a test section to detect and familiarize with its construction performance, thereby ensuring that the formal construction in the filed can proceed smoothly.
• (2) Preparing of materials and calibrating of a concrete mixing vehicle
• The concrete mixing vehicle in the present application is a new equipment with an integrated function of mixing, transporting and pouring the concrete. This equipment can effectively solve the problem that the quick-drying concrete used in construction has a short coagulation time and is not suitable for long-distance transportation. Also, it has the advantages of ready-to-use and cast-in-place, convenient and fast, accurate measurement, and fast discharge. Before construction in the site, the quick-drying cement, gravel, water and other materials required for construction are loaded in corresponding silos of the concrete mixing vehicle, and are weighed at the same time to ensure that the concrete mixing volume of the current day can be met. The amount of material feeding must exceed the design demand of the current day by 20% to prevent insufficient material feeding due to loss and other factors. After the material feeding is completed, each silo of the all-in-one vehicle shall be closed and covered to prevent spilling. A metering equipment of the concrete mixing vehicle is calibrated after the material feeding is completed, and at the same time a small amount of concrete is mixed for test, and a construction mix ratio of the current day is determined according to the state of the concrete.
• (3) Entering the site and positioning the slab to be replaced
• The position where the slab needs to be quickly replaced is determined according to the design requirements.
• (4) Construction preparation before breaking the slab
• Before breaking the slab, the navigation aid lamps on the damaged slab are removed, and geotextiles are laid on the adjacent slabs at the same time to prevent the broken concrete blocks from falling on and hurting adjacent slabs. Before breaking the slab, an electric pick may be used to manually trim out a protective layer with a width of not less than 15 cm and a depth of not less than 10 cm along the joint of the damaged slab to prevent damage to adjacent slabs when the slab is broken by a large machine.
• (5) Breaking the slab with a breaker
• A breaker is used to break the slab from the middle position. After the middle portion of the slab is broken, the broken concrete blocks are taken out to release the stress in the slab interior so as to prevent the broken slab from pressing and damaging the adjacent slabs, and then the breaking is carried out toward the slab edge in turn. The region with width of 15 cm at the slab edge of the damaged slab is reserved for manual breaking.
• (6) Removing concrete blocks and manual cleaning
• After breaking of the slab is completed, the concrete blocks are removed with an excavator, and fragments at the bottom are manually cleared up until a dense and flat base layer is obtained.
• (7) Laying of geotextiles and wetting the bottom by sprinkling
• After the cleaning, the geotextiles are laid, and the bottom is wet by sprinkling the water.
• (8) Pouring a first layer of concrete with the concrete mixing vehicle in place
• Due to the construction performance of the quick-drying concrete used in this process, the concrete pouring construction adopts two-layered pouring. When the thickness of a concrete slab is 40 cm, the pouring thickness of the first layer is preferably 15 cm, and the thickness of the second layer is preferably 25 cm. The pouring of the second layer of concrete is required to be completed before the initial setting of the first layer of concrete to prevent cold joints. During the pouring process, two high-frequency insertion vibrators are used to vibrate at a discharge port while pouring.
• (9) Laying steel meshes
• After pouring the first layer of concrete with 15 cm thick is completed, steel meshes are installed for reinforcement.
• (10) Pouring a second layer of concrete
• After the installation of the reinforcement steel meshes is completed, a second layer of concrete is immediately poured in a sequence from one side of the slab to the other. During pouring, leveling and mud extracting are performed on the concrete surface with a double steel tube vibrating beam.
• When the pouring concrete on two adjacent slabs at the same time, in order to prevent the formation of a cold joint between the two layers when the two slabs are simultaneously poured in a layered manner, a half-height molding board is arranged in the middle of the gap between the two adjacent slabs, that is, the height of the half-height molding board is ½ of the thickness of the slab; then the two adjacent slabs are poured in a layered manner separately. The sequence for pouring is: erecting the half-height molding board→pouring a first layer of a first slab→pouring a second layer of the first slab→removing the half-height molding board→pouring a first layer of a second slab→pouring a second layer of the second slab.
• (11) Exact leveling and surface finishing
• After the leveling and mud extracting with the double steel tube vibrating beam is completed, the concrete surface is scraped with an aluminum alloy scraper. The cement slurry at the slab edge of the adjacent slabs must be cleaned up before scraping. During scraping, the bug holes are filled with concrete aggregate, while excessive material are shoveled away with a shovel. After the scraping, the surface finishing is performed with a plastic trowel for twice and an iron trowel for twice.
• (12) Curing
• When hands cannot press into the concrete surface and the concrete surface starts to heat up, a curing is performed by sprinkling water with a sprayer. During the early of the curing, instead of aim the nozzle of the sprayer directly at the concrete surface, the nozzle should face upwards so that the water mist can naturally fall on the concrete surface. It should ensure that the concrete surface is moist during the curing and the curing time should not be less than 3 hours.
• (13) Slitting and grooving
• According to the performance of the quick-drying concrete used in this process, processes of slitting and grooving are carried out 1.5 hours after the pouring is completed.
• (14) crack sealing and recovery of the maker line
• Since the concrete curing, slitting and grooving are wet operations, processes of crack sealing and recovery of the maker line cannot be carried out. Thus, processes of crack sealing and recovery of the maker line may be conducted on the next day.

In sum, the embodiments of the present application provide a construction process of fast overall replacement of a damaged pavement slab in civil aviation non-suspend construction, which solves the limitations of the traditional pavement slab repair process. The present application first reinforces the damaged pavement slab foundation through grouting construction to solve the problems of slab bottom vacancy, foundation settlement, and insufficient bearing capacity of the base; then uses the early-strength rapid-curing concrete suitable for rapid overall slab replacement of the pavement to carry out overall replacement construction for the damaged pavement slab. The present application effectively solves the contradiction between construction period and construction quality, and has the advantages of significantly shortening construction period, improving construction quality, reducing equipment and labor input, etc., and can achieve good economy benefits and social benefits.

Those of ordinary skill in the art can understand that the drawings are only schematic diagrams of an embodiment, and the modules or processes in the drawings are not necessary for implementing the present application.

The above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or modifications within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A construction process for quickly and integrally replacing a damaged pavement slab without suspending flights of civil aviation, comprising:

a first stage: reinforcing a foundation of a damaged pavement slab by grouting; and

a second stage: integrally replacing the damaged slab with early-strength and quick-drying concrete.

2. The construction process according to claim 1, wherein the first stage comprises:

(1) positioning of a slab to be grouted: positioning and marking the damaged slab and adjacent slabs thereof;

(2) positioning of grout holes: arranging the grout holes according to an effective diffusion radius of slurry, and shape and size of the pavement slab;

(3) drilling and blowing holes: drilling holes on the pavement to penetrate a base layer into a soil subgrade, and blowing the holes to clean dust in the holes after the drilling is completed, wherein the grouting is performed after the blowing is completed;

(4) preparing of slurry: preparing slurry while positioning the grout holes in the site;

(5) grouting: grouting the slurry into the grout holes;

(6) pressure relief and sealing holes: after the grouting is completed, pulling out a grouting tube when a grouting pressure is dissipated; and after the grouting tube is pulled out, sealing the holes with a quick-drying cement mortar;

(7) testing of grouting effect: performing HWD deflection test on the grouted reinforcement area 28 days later after the grouting is completed, to determine whether slab edge deflection/slab interior deflection<2 and slab corner deflection/slab interior deflection<3, which indicate a good status of the foundation, and if yes, performing a next stage of replacement construction; and if not, performing the above steps (1) to (6) until the test results meet the above requirements.

3. The construction process according to claim 1, wherein the second stage comprises:

(1) selecting of quick-drying concrete and performing of performance test: selecting a slab replacement material and performing laboratory mixing test to the selected material before construction in the site, and performing construction on a test section in the site to detect and familiarize with construction performance of the selected material;

(2) preparing of material and calibrating of a concrete mixing vehicle: before construction in the site, loading materials required for construction into corresponding silos of a concrete mixing vehicle and weighing the concrete mixing vehicle, wherein the concrete mixing vehicle has an integrated function of mixing, transporting and pouring; calibrating a metering equipment of the concrete mixing vehicle after the loading is completed, mixing a small amount of concrete for test, and determining a construction mixture ratio for the current day according to state of the concrete;

(3) entering site and positioning of slab to be replaced: determining a position where a slab is required to be quickly replaced according to design requirements;

(4) construction preparation before breaking of the slab: before breaking the slab, removing navigation aid lamps on the damaged slab, laying geotextiles on adjacent slabs, and manually trimming out edges of the damaged slab along joints of the damaged slab with an electric pick;

(5) breaking of the slab with a breaker: using breaking the damaged slab with a breaker from middle position of the slab, taking out the broken concrete blocks after the middle portion of the slab is broken, and breaking the slab toward the slab edge in turn, wherein the slab edge of the damaged slab is reserved for manual breaking;

(6) removing concrete blocks and manual cleaning: after the breaking of the damaged slab is completed, removing concrete blocks, and manually clearing up fragments at the bottom of base layer until a dense and flat base layer is obtained;

(7) Laying of geotextiles and wetting the bottom by sprinkling: after the cleaning, laying the geotextiles, and wetting the bottom by sprinkling the water;

(8) pouring a first layer of concrete with the concrete mixing vehicle in place;

(9) laying steel meshes: after pouring of the first layer of concrete is completed, installing steel meshes for reinforcement;

(10) pouring a second layer of concrete: after the installation of the reinforcement steel meshes is completed, immediately pouring a second layer of concrete in a sequence from one side of the slab to the other, and during pouring, performing processes of leveling and mud extracting on concrete surface with a double steel tube vibrating beam;

(11) exact leveling and surface finishing: after the processes of leveling and mud extracting with the double steel tube vibrating beam is completed, scraping the concrete surface with an aluminum alloy scraper, wherein cement slurry at the slab edge of adjacent slabs is cleaned up before the scraping, and during scraping, the bug holes are filled with concrete aggregate and excessive material are shoveled away with a shovel; and performing surface finishing after the scraping;

(12) Curing: carrying out a process of a water spray curing;

(13) slitting and grooving: performing processes of slitting and grooving according to performance of the quick-drying concrete used; and

(14) sealing crack and recovering maker lines.

4. The process according to claim 2, wherein in drilling and blowing holes, a drill bit of a drilling rig used for drilling holes on the pavement is not greater than 60 mm; the drilling holes penetrates the base layer into the soil subgrade by 10 cm; after reaching a design depth, an air compressor is used to blow the holes, and the blowing time is not less than 10 s.

5. The construction process according to claim 2, wherein technical indicators to be controlled during the grouting process comprise:

(1). grouting pressure: when grouting on airport pavement, a grouting pressure is not greater than 1.0 MPa; when the grouting pressure is maintained at a certain value and the amount of grouting is no longer increased during the grouting, the grouting is stopped;

(2). slab surface elevation: an allowable elevation of the pavement slab during the grouting is no more than 5 mm, a final allowable elevation of the pavement slab after stabilization is not greater than 3 mm, and when the slab elevation is greater than 5 mm, the grouting is stopped; and

(3). slurry overflowing situation around the slab: the grouting is stopped when a large of slurry overflows around the pavement slab during the grouting, and the overflowing slurry is cleaned up in time.

6. The construction process according to claim 3, wherein in the construction preparation before breaking of the slab, manually trimming out, by using an electric pick, a protective layer with a width of not less than 15 cm and a depth of not less than 10 cm along joint of the damaged slab to prevent damage to adjacent slabs when the slab is broken by a large machine.

7. The construction process according to claim 3, wherein in the breaking of the slab with a breaker, a region with width of 15 cm at the slab edge of the damaged slab is reserved for manual breaking.

8. The construction process according to claim 3, wherein when the thickness of a concrete slab is 40 cm, pouring thickness of the first layer is 15 cm, and the thickness of the second layer is 25 cm; the pouring of the second layer of concrete is completed before initial setting of the first layer of concrete to prevent cold joints.

9. The process according to claim 3, wherein in pouring of concrete on two adjacent slabs at the same time, in order to prevent formation of a cold joint between the two layers when the two slabs are simultaneously poured in a layered manner, arranging a half-height molding board in middle of gap between the two adjacent slabs, wherein height of the half-height molding board is ½ of thickness of a slab; pouring concrete on the two adjacent slabs in a layered manner separately, wherein a sequence for pouring is: erecting the half-height molding board→pouring a first layer of a first slab→pouring a second layer of the first slab→removing the half-height molding board→pouring a first layer of a second slab→pouring a second layer of the second slab.

10. The construction process according to claim 3, wherein the water spray curing comprises: when hands cannot press into concrete surface and the concrete surface starts to heat up, performing the curing by sprinkling water with a sprayer, wherein a nozzle of the sprayer faces upwards during the early of the curing so that water mist fall on the concrete surface; it is ensure that the concrete surface is moist during the curing and the curing time is not less than 3 hours.