Single-lane concrete pavement structure for preventing and treating mid-suture cracking and construction method thereof
By creating anti-crack grooves and laying impermeable materials under the concrete pavement, the stress pattern of a single-lane pavement was improved, the problem of cracking in the middle of the cement concrete pavement was solved, and the load-bearing capacity and durability of the pavement were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2025-03-21
- Publication Date
- 2026-08-04
AI Technical Summary
Cement concrete pavements are prone to defects such as cracks and broken slabs during use, especially single-lane pavements where cracking at the center joints due to poor stress distribution is difficult to prevent effectively.
Crack-resistant grooves are opened along the centerline of the road beneath the concrete surface layer, and impermeable geotextile or membrane is laid in the grooves to improve the stress condition of the lower part of the panel and reduce tensile stress and displacement by adjusting the base structure.
It effectively prevents cracks and breakage of concrete pavement panels, improves load-bearing capacity, is easy to construct and low in cost, and significantly improves the durability of pavement structures.
Smart Images
Figure CN119956642B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of roadbed and pavement engineering technology, specifically to a single-lane concrete pavement structure and construction method for preventing cracking in the center joint. Background Technology
[0002] Cement concrete pavements are widely used in road construction in my country. However, a series of defects in cement concrete pavements, such as cracks and broken slabs, seriously affect their service life. This not only wastes resources but also disrupts normal traffic flow. Once broken slabs occur in cement concrete pavements, many of their advantages disappear, and the difficulty of repair becomes very prominent. Because cement concrete has high rigidity, the fracture of cement slabs is a brittle fracture, which is sudden and difficult to repair once it occurs.
[0003] Previous research has largely focused on preventing and controlling such defects by addressing factors such as materials, cement concrete mix proportions, and meticulous construction details. For example, this includes strict control over cement concrete mix proportions, timely and accurate joint cutting after cement concrete pavement construction, and control of construction material quality. However, research on improving the underlying conditions of cement concrete pavement slabs is relatively limited.
[0004] Cracks and broken slabs in concrete pavement structures have multiple mechanisms and causes. Some broken slabs are caused by tensile stress exceeding the tensile strength of concrete due to hindered initial shrinkage during construction; others are caused by temperature warping stress exceeding the flexural strength of concrete due to excessively large slab sizes; still others are caused by excessive vehicle loads, stress concentration, or damage to the joint filler leading to voids under the slab. Concrete pavement structures fall under the theory of elastic foundation plates, with the underlying elastic semi-space foundation significantly influencing the stress on the concrete slab. The occurrence of defects is closely related to the elastic semi-space foundation beneath the concrete slab.
[0005] Extensive research revealed that, due to factors such as narrow roadbeds, road camber, roadbed creep, and vehicle loads, a large number of defects in single-lane cement concrete slabs are concentrated in longitudinal cracks and slab breaks. For example... Figure 1 As shown, under vehicle load, the concrete panel forms a three-point flexural stress pattern with the center supporting upwards and both ends downwards, leading to upward bending and fracture, resulting in cracks and slab breaks at the center of the concrete panel. Therefore, how to change the stress pattern of the concrete surface layer is an urgent technical problem to be solved in the prevention and control of this type of defect in cement concrete panels. Summary of the Invention
[0006] The purpose of this invention is to improve the semi-space elastic foundation and its stress condition under the concrete pavement panel, so as to solve the problems of cracks, broken panels and other defects in the concrete pavement panel.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] On the one hand, the present invention provides a single-lane concrete pavement structure for preventing cracking in the center joint, wherein anti-crack grooves are opened on the surface of the base layer along the center line of the road, the anti-crack grooves are located below the concrete surface layer, and the interior of the anti-crack grooves is flat and without filler.
[0009] Furthermore, a layer of impermeable geotextile or film is provided between the crack-resistant groove and the concrete surface layer.
[0010] Furthermore, the width of the anti-crack groove is one-third of the width of the concrete surface layer, and the depth of the anti-crack groove is 5-10cm.
[0011] Furthermore, the anti-crack groove is located at the center below the concrete surface layer, and the length of the anti-crack groove is consistent with that of the concrete surface layer.
[0012] On the other hand, the present invention provides a construction method for a single-lane concrete pavement structure to prevent cracking at the center joint, comprising the following steps:
[0013] Compacting involves rolling and compacting the base layer.
[0014] After the trenching and overall compaction of the base course are completed, the base course fill material within a certain width and depth range of the road centerline is loosened.
[0015] Level the surface, removing and leveling away any excess base material.
[0016] Furthermore, during trenching, the excavation width is determined along the road centerline. A backhoe excavator or manual labor is used to loosen the base fill material within one-third of the road slab width and a depth of 5-10cm from top to bottom.
[0017] Furthermore, after the trenching is completed, a layer of impermeable geotextile or film is covered on the anti-crack trench before concrete pavement is poured.
[0018] Furthermore, during leveling, the filler in the grooves is removed but not compacted.
[0019] Beneficial effects: This invention improves the underlying stress state of concrete slabs, maximizes their load-bearing capacity, and solves problems such as cracks and broken slabs in concrete pavement slabs. The method of this invention is simple to construct, has low construction costs, and is reliable in its effects. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of this invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be mechanically analyzed and explained below. The drawings described below are some embodiments of this invention.
[0021] Figure 1 This is a schematic diagram of the stress on a traditional cement concrete panel for a single-lane road.
[0022] Figure 2 This is a schematic diagram of the stress distribution on a single-lane concrete pavement structure designed to prevent cracking at the center joint.
[0023] Figure 3 This is a rendering of the mesh generation effect for a loose groove model of a cement concrete pavement base course.
[0024] Figure 4 This is a schematic diagram showing the location of the standard load applied by the finite element method.
[0025] Figure 5 The variation of maximum tensile stress and maximum vertical displacement of a single-lane cement concrete slab with the width of the riprap.
[0026] Figure 6 The variation of maximum tensile stress and maximum vertical displacement of a single-lane cement concrete slab with groove depth.
[0027] Figure 7 The graph shows the variation of maximum tensile stress and maximum vertical displacement of a single-lane cement concrete slab with axle load. Detailed Implementation
[0028] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0029] like Figure 2 As shown, this example is a single-lane concrete pavement structure for preventing center-joint cracking. Specifically, anti-crack grooves are opened on the surface of the base layer along the centerline of the road. The anti-crack grooves are located below the concrete surface layer and are flat and free of filler inside.
[0030] Preferably, a layer of impermeable geotextile or film is provided between the crack-resistant groove and the concrete surface layer.
[0031] Preferably, the width of the anti-crack groove is one-third of the width of the concrete surface layer, and the depth of the anti-crack groove is 5-10cm.
[0032] Preferably, the anti-crack groove is located at the center below the concrete surface layer, and the length of the anti-crack groove is consistent with that of the concrete surface layer.
[0033] The specific construction methods for the above-mentioned road surface structure are as follows:
[0034] Before construction, ensure smooth access to the construction site and set up storage areas for construction equipment and materials.
[0035] After the second base course is compacted, the location is measured, leveled, and the excavation width is determined along the road centerline. Using a backhoe excavator or manually, the base course fill material within one-third of the road slab width and a certain depth of 5-10cm is loosened from top to bottom.
[0036] Third, use a leveling machine or manual labor to remove and level the excess filler in the trough, but do not compact it.
[0037] To prevent grout leakage from cast-in-place road surface concrete, a layer of impermeable geotextile or film can be covered on the loose groove.
[0038] Fourth, the construction and maintenance of concrete pavement slabs shall be carried out in accordance with the relevant concrete pavement construction technical specifications.
[0039] Using ANSYS finite element software calculations as the theoretical basis, a model is established as follows: Figure 3 As shown, the load type used in this experiment is a standard axle load of a single axle with two wheels. According to the principle of load stress equivalence, the uniformly distributed double-circle load can be converted into a rectangular load for easier mesh generation. The axle weight is 100 kN, the tire inflation pressure (i.e., the vehicle axle weight) is 0.7 MPa, and the equivalent ground contact area of the wheels is represented by a rectangle with tire dimensions of 0.23 m × 0.16 m. The inner distance between the two wheels is 0.16 m, the front-to-rear wheelbase is 2.6 m, and the static load application location is as follows: Figure 4 As shown.
[0040] The following is a further detailed description of the dimensions and structure of the loose groove in the cement concrete base of a single-lane road.
[0041] Influence of base course trench width on the structural mechanical response of a single-lane cement-concrete slab structure
[0042] According to the specifications, the width of cement concrete surface slabs should be 3.0m to 4.5m, the length-to-width ratio should be 1 to 1.35, and the planar area should not exceed 25m². 2 Based on on-site research, the width of the single-lane cement concrete pavement slab is 3.5m. The "Specifications for Design of Cement Concrete Pavement on Highways" stipulates that the length of the cement concrete pavement slab should be 4.0m to 6.0m; a length of 4.0m and a thickness of 0.22m are selected. The widths of the grooves are selected as 1 / 2, 1 / 3, 1 / 4, and 1 / 5 of the slab width, respectively. The depth is selected as 10cm. The bending tensile stress and vertical displacement of the entire pavement slab are selected as evaluation indicators for the pavement structure's mechanical response.
[0043] Depend on Figure 5(a) A significant positive correlation can be observed: as the groove width increases from 0.7 m to 1.75 m, the maximum tensile stress increases from 0.641 MPa to 0.718 MPa. The maximum increase in maximum tensile stress is as large as 8.45%. Figure 5 (b) The maximum vertical displacement exhibits an inverted V-shaped change. The vertical displacement increases by 0.003 mm from 0.7 m to 1.17 m, and decreases by 0.001 mm from 1.17 m to 1.75 m. In subsequent designs, the width of the vertical displacement groove for the single-lane concrete base course is selected as 1 / 3 of the panel width.
[0044] Influence of base course trench depth on the structural mechanical response of a single-lane cement-concrete slab structure
[0045] The length of the loosening groove is the same as the normal road surface length, the width is 1 / 3 of the width of the concrete slab, and the depth is 5cm, 10cm, 15cm, and 20cm respectively. The influence of the loosening groove depth on the mechanical response of the single-lane cement concrete slab structure is analyzed, with only the loosening groove depth adjusted while keeping other parameters unchanged.
[0046] like Figure 6 As shown in (a), as the groove depth increases from 5 cm to 20 cm, the maximum tensile stress first decreases from 0.665 MPa to 0.662 MPa, and then begins to rise to 0.672 MPa. Figure 6 (b) It can be seen that the change in groove depth has little effect on the maximum vertical displacement of the panel. The maximum vertical displacement changes by only 0.001 mm when the groove depth increases from 5 cm to 20 cm. In the subsequent design, a groove depth of 10 cm was selected for the single-lane concrete base.
[0047] Six different axle loads were selected for calculation, with wheel pressure ranging from 0.4 MPa to 0.7 MPa. The corresponding calculation results are shown in Table 1.
[0048] Table 1 Calculation results of tire ground pressure stress under different overload conditions
[0049]
[0050] Axle loads are increased sequentially by 20% of the design standard, while other parameters remain unchanged. The maximum tensile stress σ in the single-lane cement concrete slab, regardless of whether there are loose grooves, is also considered. y max and maximum vertical displacement w L max The calculation results are shown in Table 2.
[0051] Table 2 Calculation results of mechanical response of single-lane cement concrete slab as a function of slab length
[0052]
[0053] From Table 2 and Figure 7It can be known that:
[0054] (1) Axle load has a significant impact on the maximum tensile stress and maximum vertical displacement of the load-bearing slab. As the design axle load increases from 100KN to 200KN, the maximum tensile stress of the single-lane cement concrete slab is 0.846MPa and the maximum vertical displacement is 3.069mm when the overload rate is 0%. When the overload rate is 100%, the maximum tensile stress of the single-lane cement concrete slab is 1.51MPa and the maximum vertical displacement is 3.839mm. The maximum tensile stress of the load-bearing slab increases by an average of 12.4%, and the maximum vertical displacement increases by an average of 15.9%. Therefore, overload has a significant impact on the stress and displacement in the pavement structure and is one of the main factors causing slab breakage in cement concrete pavements.
[0055] (2) Loosening the axle groove significantly improves the maximum tensile stress and displacement of single-lane concrete slabs under overload conditions. Under different design axle loads, compared with single-lane concrete slabs without loosening the axle groove, the maximum tensile stress and maximum vertical displacement of the concrete slabs with loosening the axle groove are reduced. The maximum tensile stress is reduced by a maximum of 0.333 MPa, with an average reduction of 28.4%. The maximum vertical displacement is reduced by a maximum of 0.037 mm, with an average reduction of 1.1%. In comparison, the impact on vertical displacement is relatively small. Therefore, loosening the axle groove in the base layer can significantly improve the tensile stress of single-lane concrete slabs under overload conditions and has a certain degree of improvement on the vertical displacement of single-lane concrete slabs.
[0056] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.
Claims
1. A single-lane concrete pavement structure for preventing cracking at the center joint, characterized in that, Anti-crack grooves are opened on the base surface along the centerline direction of the road. The anti-crack grooves are located below the concrete surface layer. The inside of the anti-crack grooves is flat and without filler. The width of the anti-crack grooves is one-third of the width of the concrete surface layer, and the depth of the anti-crack grooves is 5-10cm. The construction method for the road surface structure includes the following steps: Compacting involves rolling and compacting the base layer. After the trenching and overall compaction of the base course are completed, the base course fill material within a certain width and depth range of the road centerline is loosened. Leveling involves removing and leveling off excess base material; after leveling, the filler in the groove is removed but not compacted.
2. A single-lane concrete pavement structure for preventing joint cracking as described in claim 1, characterized in that, A layer of impermeable geotextile or film is provided between the anti-crack groove and the concrete surface layer.
3. A single-lane concrete pavement structure for preventing joint cracking as described in claim 1, characterized in that, The anti-crack groove is located at the center below the concrete surface layer, and the length of the anti-crack groove is the same as that of the concrete surface layer.
4. A single-lane concrete pavement structure for preventing joint cracking as described in claim 1, characterized in that, When trenching, determine the excavation width along the centerline of the road, and use a backhoe excavator or manual labor to loosen the base fill material within one-third of the road slab width and 5-10cm depth from top to bottom.
5. A single-lane concrete pavement structure for preventing joint cracking as described in claim 1, characterized in that, After the trench is cut, cover the anti-crack trench with a layer of impermeable geotextile or film, and then pour the concrete pavement.