Splicing construction method for new road and old road of cement-stabilized base

Abstract

The invention discloses a cement-stabilized base new and old road splicing construction method which comprises the following steps: milling old road steps on one side, close to a new road, of the old road according to the structure of a new road cement-stabilized base; the lap joint faces of the old road steps are cleaned; before paving, spraying wet cement paste on the lapped surface of the steps of the old road, and smearing thickened cement paste on a roadbed 8-12m in front of a paver; paving is conducted in an abutted seam attaching mode, and in the paving process, drip irrigation cement paste is poured into the abutted seam position formed by splicing of the new road and the old road; after paving is completed, initial pressing, re-pressing, final pressing and curing are conducted in sequence, and splicing construction of the new road and the old road of the water-stabilized base is completed; wherein after initial pressing and before re-pressing, cement paste is poured and filled in the abutted seam position formed by splicing of the new road and the old road. According to the invention, close combination between the new and old road water-stable base layers can be improved, horizontal shear force and vertical pressure in the vehicle driving process can be resisted together, and the road structure can be kept stable in long-term use.

Description

Technical Field

[0001] The invention relates to the technical field of expansion engineering, and in particular to a construction method for splicing a new road with an old road on a water-stable base. Background Art

[0002] With the development of the economy, the traffic volume in many areas has shown a trend of continuous growth. The traffic carrying capacity considered in the design of the original roads can no longer meet the current needs. For example, some roads around cities may only serve a small number of local vehicles in the early stage of construction, but with the acceleration of urbanization and the development of surrounding areas, a large number of commuter vehicles and freight vehicles began to use these roads, resulting in road congestion and increased road damage. In order to improve the traffic capacity of the road, road expansion has become an inevitable choice. During the expansion process, how to deal with the splicing of the new and old roads, especially the splicing of the water-stable base, is a key link in ensuring the overall quality of the road.

[0003] However, the existing technology has the following main disadvantages when splicing the new and old roads on the water-stable base:

[0004] At the junction of the new and old roads, if the shear strength is insufficient, interlayer sliding is likely to occur between the newly paved water-stable base and the old road base under the influence of vehicle loads and temperature stress.

[0005] The new and old roadbeds may have different deformations due to factors such as material properties and construction time. Under temperature changes, humidity changes, and long-term loads, their deformation amounts and deformation rates may be different.

[0006] When vehicles are driving on the road, they exert vertical pressure on the road surface. At the joint of the new and old roads, this pressure needs to be borne by the newly paved water-stable base and the old road base. If the compressive strength of the joint is not greater than the design value, the joint will be easily crushed under the load of the vehicle, resulting in road dents and other defects.

[0007] In view of this, the present invention is proposed. Summary of the invention

[0008] The purpose of the invention is to provide a construction method for splicing a new and old road with a water-stable base, so as to improve the compressive strength and shear strength of the joint position.

[0009] The present invention is achieved in that:

[0010] In a first aspect, the present invention provides a construction method for splicing a new and old road with a water-stable base, comprising:

[0011] Step 1: According to the structure of the new road water-stable base, mill the old road steps on the side of the old road close to the new road, so that each layer of the new road water-stable base can overlap the corresponding position of the old road steps;

[0012] Step 2: Clean the overlapping surface of the old road steps;

[0013] Step 3: Before paving, spray wet cement slurry on the overlapping surface of the old road steps, and apply thickened cement slurry on the roadbed 8-12m in front of the paver;

[0014] Step 4: Pave the road by pasting the joints, and during the paving process, pour drip irrigation cement slurry into the joints formed by the new and old roads;

[0015] Step 5: After paving is completed, initial compaction, re-compacting, final compaction and curing are carried out in sequence to complete the splicing construction of the new and old roads of the water-stable base; wherein, after the initial compaction and before the re-compacting, cement slurry is poured into the joints formed by the splicing of the new and old roads.

[0016] In an optional implementation, in step 1, the width of each layer of the old road steps is ≥ 20 cm.

[0017] In an optional embodiment, in step 2, a high-pressure water gun combined with a wire brush is used to clean loose objects, pollutants and moss on the step overlap surface.

[0018] In an optional embodiment, the water-cement ratio of the wet cement slurry is 2-3.

[0019] In an optional embodiment, the water-cement ratio of the thickened cement slurry is 0.2-1;

[0020] And / or, the thickened cement slurry has a coating thickness of 0.5-1 cm;

[0021] In an optional embodiment, the water-cement ratio of the drip irrigation cement slurry is 1.5-2.5;

[0022] In an optional embodiment, the device for drip-irrigating the drip irrigation cement slurry moves synchronously with the paver, and the drip irrigation rate of the drip irrigation cement slurry is 150-250 mL / min.

[0023] In an optional embodiment, the water-cement ratio of the filling cement slurry is 1.5-2.5;

[0024] And / or, the filling cement slurry is poured into a long strip area with a width of 15 cm along the joint direction.

[0025] In an optional embodiment, the old road steps and the mixture on the top surface of the formwork are cleaned before re-pressing.

[0026] In an optional embodiment, after seven days of curing, the shear test result of the core sampling across the seam is ≥0.4MPa, or the compression test result of the seam is ≥the design value.

[0027] The present invention has the following beneficial effects:

[0028] The construction method for splicing the new and old roads with the water-stable base provided by the present invention can improve the close connection between the new and old water-stable bases, jointly resist the horizontal shear force during vehicle driving, and ensure that the road structure remains stable during long-term use; since different base materials and construction times will cause the new and old road bases to have different deformation trends under the influence of load and environmental factors, the present application can better coordinate such deformation differences.

[0029] The construction method for splicing a new and old road with a water-stable base provided by the present invention can improve the close connection between the new and old road water-stable bases, so that the joint parts can withstand greater vertical pressure, ensuring that the joint parts remain stable under heavy load conditions, which is beneficial to improving the overall bearing capacity of the road structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a schematic diagram of the new and old road splicing structure in Example 1 of the present application;

[0032] Figure 2 This is a schematic diagram of the new and old road splicing structure in Example 2 of the present application;

[0033] Figure 3 This is a picture of the cross-seam core sampling sample in Example 1. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0035] The embodiment of the present invention provides a construction method for splicing a new and old road with a water-stable base, comprising:

[0036] Step 1: According to the structure of the new road water-stable base, mill the old road steps on the side of the old road close to the new road, so that each layer of the new road water-stable base can overlap the corresponding position of the old road steps;

[0037] The steps of the old road are milled according to the thickness of the new road water-stable base layer, in order to ensure the connection of the new and old road structural layers in height; in some preferred implementations, the width of each layer of the old road steps is ≥20cm, and the sufficient width can provide a larger splicing area and enhance the connection stability between the new and old road base layers; for example, if the new road water-stable base layer has three layers, namely, the first water-stable base layer, the second water-stable base layer and the third water-stable base layer from top to bottom, and the water-stable base layer of the old road can be adapted to the water-stable base layer of the new road, then the milled old road steps are as follows Figure 1 As shown in the figure, ensure that the bottom surfaces of the new and old road bases are on the same horizontal plane, which is conducive to the uniform transfer of stress; if the new and old road water-stable bases cannot be adapted, the milled old road steps are as follows Figure 2 shown.

[0038] When milling old road steps, a small milling machine can be used to mill the old road. The small milling machine is small in size and flexible in operation. It is suitable for situations where the milling width and depth requirements are relatively small. When milling old road steps in some narrow areas, its milling width is generally between 30-60cm, and the milling depth can reach 5-10cm or even more; the power source of the milling machine is mostly a small internal combustion engine, and the small milling machine driven by the internal combustion engine has good maneuverability and does not need to rely on an external power supply; when the milling width of the old road steps is required not to exceed 60cm, for example, in the splicing projects of new and old roads in some branch roads or community roads, the small milling machine can accurately mill out steps that meet the requirements.

[0039] Step 2: Clean the overlapping surface of the old road steps;

[0040] Cleaning the overlapping surface of the old road steps includes cleaning loose objects, pollutants and moss. Loose objects will affect the adhesion between the new and old base layers. If they are not cleaned, cracks will easily occur in these weak parts when the new and old base layers are subjected to force; pollutants such as oil stains will hinder the adhesion of cement slurry to the surface of the base layer, and the presence of moss will also reduce the adhesion effect; for example, oil stains on the road are generally caused by leakage from passing vehicles, and moss is caused by the long-term humid environment of the old road. They will form an isolation layer between the new and old base layers; in some implementation methods, when cleaning the overlapping surface of the old road steps, a high-pressure water gun and a wire brush are used in combination. The high-pressure water gun can effectively flush away loose objects and moss. For stubborn pollutants, a wire brush is used for further cleaning to ensure that the overlapping surface is clean and tidy.

[0041] Step 3: Before paving, spray wet cement slurry on the overlapping surface of the old road steps, and apply thickened cement slurry on the roadbed 8-12m in front of the paver;

[0042] The wet cement slurry is spread on the step overlap surface, the main purpose of which is to moisten the base overlap surface in preparation for subsequent paving and bonding; in some embodiments, the water-cement ratio of the wet cement slurry is 2-3, preferably 2.5, and the larger water-cement ratio allows the cement slurry to have better fluidity and be able to fully penetrate into the pores on the surface of the base; for example, on the dry base surface, the cement slurry fills the tiny pores, and when the new water-stabilized mixture is spread, it can better bond with the base; for the spraying amount of wet cement slurry, at least the surface of the old road step overlap surface needs to be fully moistened.

[0043] In addition, the thickened cement slurry is applied within 8-12m, preferably 10 meters in front of the paver because paving is about to be carried out in this area. The thicker cement slurry can form a certain bonding strength in a short time, providing better initial bonding for the newly paved water-stabilized base layer. In some embodiments, the water-cement ratio of the thickened cement slurry is 0.2-1, preferably 0.5, and the application thickness of the thickened cement slurry is 0.5-1cm. The thickened cement slurry is used in combination with the wet cement slurry, which can not only ensure the early wet penetration, but also provide a better bonding effect during paving.

[0044] Step 4: Pave the road by pasting the joints, and during the paving process, pour drip irrigation cement slurry into the joints formed by the new and old roads;

[0045] Paving along the joints and spreading the mixture through the paver screed to avoid segregation are the keys to ensuring the quality of the joints between the new and old roads. Paving along the joints can make the newly paved mixture fit closely with the old road base and reduce the gaps at the joints. The vibration and ironing functions of the paver screed can evenly distribute the mixture and avoid segregation. Compared with rolling along the joints, rolling along the joints can more effectively transfer the pressure of the roller to the joints, which is beneficial to improve the density and strength of the joints.

[0046] Drip irrigation cement slurry has moderate fluidity and adhesion. It drips continuously during the paving process to continuously replenish the bonding materials at the joints of the new and old base layers, ensuring that the new and old base layers always maintain a good bonding state during the continuous filling and compaction of the mixture. For example, as the paver moves forward, the newly laid mixture will exert a certain amount of extrusion on the joints, and the drip irrigation cement slurry can fill the gaps that appear.

[0047] In some embodiments, the water-cement ratio of the drip irrigation cement slurry is 1.5-2.5, preferably 2.0. This cement slurry with good fluidity makes it easier to diffuse in the gap during drip irrigation; in some embodiments, the device for drip irrigation of the drip irrigation cement slurry moves synchronously with the paver, and the drip irrigation rate of the drip irrigation cement slurry is 150-250mL / min. If the drip irrigation rate is too fast, the cement slurry will overflow from the joints, which will affect the construction.

[0048] It should be noted that, in some embodiments, the device for drip irrigating the drip irrigation cement slurry may include a drip irrigation cement slurry storage tank. In order to prevent cement in the drip irrigation cement slurry from settling and clogging the pipeline, a stirring structure may be provided in the drip irrigation cement slurry storage tank.

[0049] Step 5: After paving is completed, initial compaction, re-compacting, final compaction and curing are carried out in sequence to complete the splicing construction of the new and old roads of the water-stable base; wherein, after the initial compaction and before the re-compacting, cement slurry is poured into the joints formed by the splicing of the new and old roads.

[0050] After the initial compaction, the base layer has been initially compacted, but there are still some tiny gaps in the joints. Pouring cement slurry is conducive to further filling these gaps and enhancing the bonding force of the joints. Pouring is carried out before re-compacting because the vibration and pressure of the roller during the re-compacting process will make the cement slurry better combine with the base layer and the mixture, thereby improving the overall strength of the joints.

[0051] In some embodiments, the water-cement ratio of the filling cement slurry is 1.5-2.5, preferably 2; in some embodiments, the filling cement slurry is poured into a long strip area with a width of 15 cm along the joint direction; for a joint with a length of 1 meter, the amount of filling cement slurry is about 5-10 liters.

[0052] In some embodiments, the old road steps and the mixture on the top surface of the formwork are cleaned before re-pressing;

[0053] And / or, compared with the non-joint positions of the new road, the joint positions are pressed more than twice.

[0054] Cleaning the mixture on the steps and the top surface of the template before re-compacting is to ensure the effect of joint-filling rolling. If there is excess mixture on the steps and the top surface of the template, it will affect the compaction effect of the roller on the joints during rolling, resulting in insufficient compaction at the joints. For example, excess mixture will cause the roller to produce a local padding phenomenon during rolling, making it impossible to fully compact the joints. Therefore, the joints can be re-compacted more than 2 times. Joint-filling rolling can ensure the compaction of the joints between the new and old bases, so that the new and old bases are better combined into a whole, which is conducive to improving the density and strength of the joints.

[0055] In an optional embodiment, after seven days of curing, the shear test result of the core sampling across the seam is ≥0.4MPa, or the compression test result of the seam is ≥the design value.

[0056] like Figure 1In the situation shown, the new road after construction can be subjected to cross-seam core shear test. The cross-seam core shear test result is ≥0.4MPa, which can ensure that the joints of the new and old road bases can remain stable when subjected to horizontal shear force. For example, during vehicle driving, especially when the vehicle brakes or accelerates, horizontal force will be generated on the road surface. The joints of the new and old road bases must have sufficient shear strength to resist this force and prevent shear damage at the joints.

[0057] like Figure 2 In the situation shown, the new road after construction can be tested for joint compression. The joint compression strength greater than the design value ensures that the joint of the new and old road base can withstand the vertical pressure from the road surface. If the compressive strength is insufficient, dents will appear at the joint under the action of vehicle loads.

[0058] The construction method for splicing the new and old roads with the water-stable base provided by the present invention can improve the close connection between the new and old water-stable bases, jointly resist the horizontal shear force during vehicle driving, and ensure that the road structure remains stable during long-term use; since different base materials and construction times will cause the new and old road bases to have different deformation trends under the influence of load and environmental factors, the present application can better coordinate such deformation differences.

[0059] The construction method for splicing a new and old road with a water-stable base provided by the present invention can improve the close connection between the new and old road water-stable bases, so that the joint parts can withstand greater vertical pressure, ensuring that the joint parts remain stable under heavy load conditions, which is beneficial to improving the overall bearing capacity of the road structure.

[0060] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0061] Example 1

[0062] This embodiment provides a construction method for splicing a new and old road with a water-stable base, comprising:

[0063] Step 1: According to the structure of the new road water-stable base, mill the old road steps on the side of the old road close to the new road, so that each layer of the new road water-stable base can overlap the corresponding position of the old road steps, and the step width is 30cm;

[0064] Step 2: Clean the overlapping surface of the old road steps;

[0065] Use a combination of high-pressure water gun and wire brush to flush away loose materials and moss, and use a wire brush to further clean stubborn contaminants to ensure that the lap surface is clean and tidy.

[0066] Step 3: Before paving, spray wet cement slurry with a water-cement ratio of 2.5 on the overlapping surface of the old road steps to fully wet the surface of the overlapping surface of the old road steps, and apply thickened cement slurry with a water-cement ratio of 0.5 on the roadbed 10m in front of the paver, with a thickness of 0.6cm;

[0067] Step 4: Pave the road in a jointing manner, and during the paving process, pour drip irrigation cement slurry with a water-cement ratio of 2.0 into the joints formed by the new and old roads, with a drip irrigation rate of about 200 mL / min.

[0068] Step 5: After paving is completed, initial compaction, re-compacting, final compaction and curing are carried out in sequence to complete the splicing construction of the new and old roads of the water-stable base; wherein, after the initial compaction and before the re-compacting, filling cement slurry with a water-cement ratio of 2.0 is poured into the joints formed by the splicing of the new and old roads. For a joint with a length of 1 meter, the amount of filling cement slurry is about 8 liters; at the same time, before re-compacting, clean the steps of the old road and the mixture on the top surface of the formwork; during re-compacting, the non-joint positions of the new road are compacted 6 times, and the joint positions are compacted 8 times.

[0069] The water-stable base structure obtained by construction in this embodiment is as follows Figure 1 As shown, after seven days of curing, the shear strength of the cross-seam core shear test was 0.65MPa. Figure 3 shown.

[0070] Example 2

[0071] The difference between this embodiment and embodiment 1 is that the old road water-stable base does not match the new road water-stable base structure. The construction method is the same as that of the embodiment. The water-stable base structure obtained by construction is as follows: Figure 2 As shown, after seven days of curing, the seam compression test showed that the seam compression strength was 5.8MPa.

[0072] In the prior art, after the construction of the spliced ​​water-stabilized base layer, it is usually difficult to obtain complete samples for cross-seam core shear testing or joint compression testing. During the sampling process, the samples may break due to insufficient strength. The embodiments of the present application can not only completely sample, but also obtain better test results, which is beneficial to the stability of the spliced ​​pavement.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A construction method for splicing new and old roads with a water-stable base, characterized in that: include: Step 1: According to the structure of the new road water-stable base, mill the old road steps on the side of the old road close to the new road, so that each layer of the new road water-stable base can overlap the corresponding position of the old road steps; Step 2: Clean the overlapping surface of the old road steps; Step 3: Before paving, spray wet cement slurry on the overlapping surface of the old road steps, and apply thickened cement slurry on the roadbed 8-12m in front of the paver; Step 4: Pave the road by pasting the joints, and during the paving process, pour drip irrigation cement slurry into the joints formed by the new and old roads; Step 5: After paving is completed, initial compaction, re-compacting, final compaction and curing are carried out in sequence to complete the splicing construction of the new and old roads of the water-stable base; wherein, after the initial compaction and before the re-compacting, cement slurry is poured into the joints formed by the splicing of the new and old roads.

2. The method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: In step 1, the width of each layer of the old road steps is ≥20 cm.

3. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: In step 2, a high-pressure water gun and a wire brush are used to clean loose objects, pollutants and moss on the overlapping surface of the steps.

4. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: The water-cement ratio of the wet cement slurry is 2-3.

5. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: The water-cement ratio of the thickened cement slurry is 0.2-1; And / or, the thickened cement slurry is applied with a thickness of 0.5-1 cm.

6. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: The water-cement ratio of the drip irrigation cement slurry is 1.5-2.

5.

7. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: The device for drip irrigating the drip irrigation cement slurry moves synchronously with the paver, and the drip irrigation rate of the drip irrigation cement slurry is 150-250mL / min.

8. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: The water-cement ratio of the filling cement slurry is 1.5-2.5; And / or, the filling cement slurry is poured into a long strip area with a width of 15 cm along the joint direction.

9. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: Clean the old road steps and the mixture on the top of the formwork before re-pressing; And / or, compared with the non-joint positions of the new road, the joint positions are pressed more than twice.

10. The construction method for splicing new and old roads with a water-stable base according to claim 1 is characterized in that: After seven days of curing, the shear test result of the core sampling across the seam shall be ≥0.4MPa, or the compression test result of the seam shall be ≥the design value.

Images