Partial self-stress concrete prefabricated slab for road

Abstract

The partial self-stress concrete precast slab for the road is characterized by comprising a front end plate, a self-stress plate and a rear end plate which are sequentially arranged in the length direction, the front end plate and the rear end plate are composed of common concrete, end plate longitudinal bars and end plate transverse bars, and the self-stress plate is composed of high-expansion concrete, self-stress longitudinal bars and self-stress transverse bars; the number of the self-stress longitudinal bars is equal to that of the end plate longitudinal bars, the self-stress longitudinal bars are distributed in the same state and are aligned with the end plate longitudinal bars, the aligned self-stress longitudinal bars are connected with the end plate longitudinal bars, and the pressed front end plate and the pressed rear end plate apply pressure stress to the self-stress plate through the end plate longitudinal bars and the self-stress longitudinal bars. According to the partial self-stress concrete prefabricated slab for the road, tensioning is not needed in the whole manufacturing process, and compared with an existing self-stress cement concrete prefabricated slab, the manufacturing and welding processes of a self-stress tensioning plate with the complex process are avoided, the quality of the concrete prefabricated slab is ensured, and the engineering cost is saved.

Description

Technical Field

[0001] The utility model relates to a precast concrete slab, and more specifically, to a road-use partially self-stressing precast concrete slab. Background Art

[0002] Reinforced concrete precast slabs are prone to cracking, have a low service life, and cannot withstand the tensile stress generated by vehicle loads in the driving direction. Therefore, they are not suitable for use as road slabs. In order to enable reinforced concrete precast slabs to be used as road slabs, it is necessary to make them have compressive prestress in the longitudinal direction to form prestressed reinforced concrete precast slabs to ensure the bearing capacity of driving vehicles. At present, the methods for generating prestress inside reinforced concrete are the pretensioning method and the post-tensioning method. The pretensioning method is to tension the longitudinally arranged steel bars (steel strands) before concrete pouring, and when the concrete reaches a certain strength, the steel strands are released. The released steel strands will generate longitudinal compressive stress on the precast slab; the post-tensioning method is to place corrugated pipes in the concrete. When the concrete reaches a certain strength, steel strands are placed in the corrugated pipes and tensioned, and finally grout is injected for anchor sealing.

[0003] During actual construction, in order to ensure the standard tensioning of steel strands, a tensioning platform needs to be poured for pretensioned prestressed precast slabs. The construction requirements for the tensioning platform are high and the funds are large, which is uneconomical for projects with limited construction sites or a small number of precast slabs. The post-tensioning method for prestressed precast slabs has a complex process and a high cost. Moreover, when manufacturing self-stressing cement concrete precast slabs that do not adopt the pretensioning method and the post-tensioning method, a large number of self-stressing tensioning plates need to be embedded on both sides of the precast slab, and the welding process between the tensioning plates and the self-stressing steel bars is complex, with high technical requirements for workers, and it is difficult to guarantee the connection quality. For this reason, the utility model proposes a precast concrete slab that can form most of the self-stress without tensioning. Summary of the Invention

[0004] The utility model overcomes the above-mentioned technical problems and provides a road-use partially self-stressing precast concrete slab.

[0005] The road-use partially self-stressing precast concrete slab of the utility model is characterized in that it includes a front end plate, a self-stressing plate, and a rear end plate arranged in sequence in the length direction. The front end plate and the rear end plate are composed of ordinary concrete and end plate longitudinal bars and end plate transverse bars poured therein. The self-stressing plate is composed of high-expansion concrete and self-stressing longitudinal bars and self-stressing transverse bars poured therein. The directions of the self-stressing longitudinal bars and the end plate longitudinal bars are consistent with the length direction of the precast slab, and the self-stressing transverse bars and the end plate transverse bars are consistent with the width direction of the precast slab. The number of self-stressing longitudinal bars is equal to the number of end plate longitudinal bars, and their distribution states are the same and aligned. The aligned self-stressing longitudinal bars and end plate longitudinal bars are connected, and the compressed front end plate and rear end plate apply compressive stress to the self-stressing plate through the end plate longitudinal bars and the self-stressing longitudinal bars.

[0006] The self-stressing longitudinal bars in the self-stressing slab of the road-use part of the utility model are formed by using the same reinforcing bar as the end-plate longitudinal bars aligned in the front end plate and the rear end plate.

[0007] For the self-stressing concrete precast slab of the road-use part of the utility model, the lengths of the front end plate and the rear end plate are 0.7 m to 1.0 m, the widths are 3.50 m to 3.75 m, the thicknesses are 25 cm to 30 cm, and the grade of the ordinary concrete is 40 MPa to 45 MPa.

[0008] For the self-stressing concrete precast slab of the road-use part of the utility model, the end-plate longitudinal bars in the front end plate and the rear end plate adopt grade-II reinforcing bars with diameters of 16 mm to 22 mm, and the spacing of the end-plate longitudinal bars is 15 cm to 30 cm. The end-plate transverse bars in the front end plate and the rear end plate adopt grade-II reinforcing bars with diameters of 12 mm to 14 mm, and the spacing of the end-plate transverse bars is 10 cm to 15 cm.

[0009] For the self-stressing concrete precast slab of the road-use part of the utility model, the length of the self-stressing slab is 6.0 m to 9.0 m, the width is 3.50 m to 3.75 m, the thickness is 25 cm to 30 cm, and the grade of the high-expansion concrete is 40 MPa to 45 MPa.

[0010] For the self-stressing concrete precast slab of the road-use part of the utility model, the self-stressing longitudinal bars in the self-stressing slab adopt grade-II reinforcing bars with diameters of 16 mm to 22 mm, and the spacing of the self-stressing longitudinal bars is 15 cm to 30 cm. The self-stressing transverse bars in the self-stressing slab adopt grade-II reinforcing bars with diameters of 16 mm to 18 mm, and the spacing of the self-stressing transverse bars is 50 cm to 70 cm.

[0011] The beneficial effects of the present utility model are as follows: The road-use part of the self-stressing concrete precast slab of the present utility model is composed of front and rear end plates located on both sides and a self-stressing plate located therebetween in the length direction. Self-stressing transverse bars and self-stressing longitudinal bars are uniformly distributed in the length and width directions of the self-stressing plate. End plate transverse bars and end plate longitudinal bars are uniformly distributed in the length and width directions of the front end plate and the rear end plate, and the aligned self-stressing longitudinal bars and end plate longitudinal bars are fixedly connected (in actual application, they are composed of the same steel bar). In this way, after the longitudinal bars and transverse bars are arranged, the front end plate and the rear end plate are first poured. After their initial setting (such as reaching 60% of the design strength), the self-stressing plate is then poured. In this way, through the expansion effect of the high-expansion concrete, compressive stress is generated on the front and rear end plates. At the same time, the front and rear end plates generate compressive stress on the self-stressing plate through the end plate longitudinal bars and the self-stressing longitudinal bars. The compressed self-stressing plate can bear the tensile stress generated during vehicle driving, making it suitable for use as a road surface slab. At the same time, the entire production process of the concrete precast slab of the present utility model does not require tensioning. Compared with the existing self-stressing cement concrete precast slab, it avoids the production and welding processes of the self-stressing tensioning slab with complex processes, ensures the quality of the concrete precast slab, and saves engineering costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a top view of the road-use part of the self-stressing concrete precast slab of the present utility model;

[0013] Figure 2 is a left view of the road-use part of the self-stressing concrete precast slab of the present utility model.

[0014] In the figure: 1 front end plate, 2 rear end plate, 3 self-stressing plate, 4 self-stressing longitudinal bar, 5 self-stressing transverse bar, 6 end plate longitudinal bar, 7 end plate transverse bar, 8 ordinary concrete, 9 high-expansion concrete. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0016] As Figure 1 shown, a top view and a left view of the road-use part of the self-stressing concrete precast slab of the present utility model are given. The shown concrete precast slab is composed of a front end plate 1, a rear end plate 2, and a self-stressing plate 3. In the length direction (i.e., the driving direction), the front end plate 1, the self-stressing plate 3, and the rear end plate 2 are arranged in sequence, that is, the self-stressing plate 3 is located between the front end plate 1 and the rear end plate 2. Both the front end plate 1 and the rear end plate 2 are composed of ordinary concrete 8 and multiple end plate longitudinal bars 6 and multiple end plate transverse bars 7 poured therein. The length directions of the end plate transverse bars 7 and the end plate longitudinal bars 6 are respectively consistent with the width and length directions of the front end plate 1 and the rear end plate 2. That is, multiple end plate longitudinal bars 6 are evenly arranged at equal intervals along the width direction of the front end plate 1 and the rear end plate 2, and multiple end plate transverse bars 7 are evenly arranged at equal intervals along the length direction of the front end plate 1 and the rear end plate 2.

[0017] The self-stressing plate 3 is composed of high-expansion concrete 9 and multiple self-stressing longitudinal bars 4 and multiple self-stressing transverse bars 5 cast therein. The length directions of the self-stressing longitudinal bars 4 and the self-stressing transverse bars 5 are respectively consistent with the length and width directions of the self-stressing plate 3. That is, multiple self-stressing longitudinal bars 4 are evenly arranged at equal intervals along the width direction of the self-stressing plate 3, and multiple self-stressing transverse bars 5 are evenly arranged along the length direction of the self-stressing plate 3.

[0018] The number of self-stressing longitudinal bars 4 in the self-stressing plate 3 is equal to the number of end-plate longitudinal bars 6 in the front end plate 1 and the rear end plate 2, and the layout states are the same. That is, multiple self-stressing longitudinal bars 4 are aligned one by one with multiple end-plate longitudinal bars 6, and the aligned end-plate longitudinal bars 6 and self-stressing longitudinal bars 4 are fixedly connected. In actual application, the self-stressing longitudinal bars 4 and the end-plate longitudinal bars 6 are formed by the same steel bar.

[0019] When manufacturing the concrete precast slab of the present utility model, after the end-plate longitudinal bars 6, end-plate transverse bars 7, self-stressing longitudinal bars 4 and self-stressing transverse bars 5 are tied up, the front end plate 1 and the rear end plate 2 are first cast. When the front end plate 1 and the rear end plate 2 reach 60% of the designed strength, the self-stressing plate 3 is then cast. Therefore, during the solidification process of the high-expansion concrete 9 that constitutes the self-stressing plate 3, the front end plate 1 and the rear end plate 2 will move outwards due to expansion. Due to the fixation of the end-plate longitudinal bars 6 in the front end plate 1 and the rear end plate 2, and the connection of the end-plate longitudinal bars 6 through the self-stressing longitudinal bars 4, the outward movement of the front end plate 1 and the rear end plate 2 will be restricted. Therefore, the front end plate 1 and the rear end plate 2 will generate compressive stress on the self-stressing plate 3. That is, the self-stressing plate 3 part in the cast precast slab is in a compressed state. The compressed self-stressing plate 3 can bear the tensile stress generated during the vehicle driving process, so that it can be used as a road surface slab.

[0020] It can be seen that for the road-use part of the self-stressing concrete precast slab of the present utility model, no steel strand needs to be set during the whole manufacturing process, no tensioning is required, so no tensioning equipment is needed, the setting of the tensioning platform in the pretensioning method is omitted, and no tensioning plate needs to be set at both ends of the precast slab, nor is it necessary to weld the tensioning plate and the steel strand. The manufacturing process is simple, and the project cost can be effectively saved.

[0021] As specific dimensional requirements, since it is used as a road slab, the thickness and width of the self-stressing slab 3 are the same as those of the front-end slab 1 and the rear-end slab 2. On the premise of satisfying the anchoring of the ends of the self-stressing longitudinal bars 4, the shorter the lengths of the front-end slab 1 and the rear-end slab 2 are, the better. In this way, it is equivalent to increasing the proportion of the self-stressing slab 3 on the road surface, which is beneficial to ensuring the firmness of the road surface. For example, the lengths of the front-end slab 1 and the rear-end slab 2 are 0.7 m to 1.0 m, the widths are 3.50 m to 3.75 m, and the thicknesses are 25 cm to 30 cm; the length of the self-stressing slab 3 is 6.0 m to 9.0 m, the width is 3.50 m to 3.75 m, and the thickness is 25 cm to 30 cm; among them, the grade of the ordinary concrete 8 is 40 MPa to 45 MPa, and the grade of the high-expansion concrete 9 is 40 MPa to 45 MPa.

[0022] In the front-end slab 1 and the rear-end slab 2, the end slab longitudinal bars 6 are made of grade-II steel bars with a diameter of 16 mm to 22 mm, and the spacing of the end slab longitudinal bars 6 is 15 cm to 30 cm. In the front-end slab 1 and the rear-end slab 2, the end slab transverse bars 7 are made of grade-II steel bars with a diameter of 12 mm to 14 mm, and the spacing of the end slab transverse bars 7 is 10 cm to 15 cm. In the self-stressing slab 3, the self-stressing longitudinal bars 4 are made of grade-II steel bars with a diameter of 16 mm to 22 mm, and the spacing of the self-stressing longitudinal bars 4 is 15 cm to 30 cm. In the self-stressing slab 3, the self-stressing transverse bars 5 are made of grade-II steel bars with a diameter of 16 mm to 18 mm, and the spacing of the self-stressing transverse bars 5 is 50 cm to 70 cm.

Claims

1. A partially self-stressed concrete prefabricated slab for road use, characterized in that: The prefabricated plate comprises a front end plate (1), a self-stress plate (3) and a rear end plate (2) which are arranged in sequence in the length direction. The front end plate and the rear end plate are composed of ordinary concrete (8) and end plate longitudinal reinforcements (6) and end plate transverse reinforcements (7) cast therein. The self-stress plate is composed of high expansion concrete (9) and self-stress longitudinal reinforcements (4) and self-stress transverse reinforcements (5) cast therein. The directions of the self-stress longitudinal reinforcements and the end plate longitudinal reinforcements are consistent with the length direction of the prefabricated plate. The self-stress transverse reinforcements and the end plate transverse reinforcements are consistent with the width direction of the prefabricated plate. The number of the self-stress longitudinal reinforcements is equal to the number of the end plate longitudinal reinforcements, and the distribution state is the same and they are aligned. The aligned self-stress longitudinal reinforcements are connected to the end plate longitudinal reinforcements. The compressed front end plate and the rear end plate exert compressive stress on the self-stress plate through the end plate longitudinal reinforcements and the self-stress longitudinal reinforcements.

2. The road-use partial self-stressed concrete prefabricated slab according to claim 1 is characterized by: The self-stressing longitudinal reinforcement (4) in the self-stressing plate (3) and the end plate longitudinal reinforcement (6) aligned in the front plate (1) and the rear plate (2) are formed by the same steel bar.

3. The road-use partial self-stressed concrete prefabricated slab according to claim 1 or 2, characterized in that: The front end plate (1) and the rear end plate (2) have a length of 0.7 m to 1.0 m, a width of 3.50 m to 3.75 m, a thickness of 25 cm to 30 cm, and the grade of the ordinary concrete (8) is 40 MPa to 45 MPa.

4. The road-use partial self-stressed concrete prefabricated slab according to claim 3 is characterized by: The end plate longitudinal reinforcement (6) in the front end plate (1) and the rear end plate (2) is made of secondary steel bars with a diameter of 16 mm to 22 mm, and the spacing between the end plate longitudinal reinforcements is 15 cm to 30 cm. The end plate transverse reinforcement (7) in the front end plate and the rear end plate is made of secondary steel bars with a diameter of 12 mm to 14 mm, and the spacing between the end plate transverse reinforcements is 10 cm to 15 cm.

5. The road-use partial self-stressed concrete prefabricated slab according to claim 1 or 2, characterized in that: The self-stressed plate (3) has a length of 6.0 m to 9.0 m, a width of 3.50 m to 3.75 m, a thickness of 25 cm to 30 cm, and a grade of the high expansion concrete (9) of 40 MPa to 45 MPa.

6. The road-use partial self-stressed concrete prefabricated slab according to claim 5, characterized in that: The self-stressed longitudinal reinforcement (4) in the self-stressed plate (3) is a secondary reinforcement with a diameter of 16 mm to 22 mm, and the spacing between the self-stressed longitudinal reinforcements is 15 cm to 30 cm. The self-stressed transverse reinforcement (5) in the self-stressed plate is a secondary reinforcement with a diameter of 16 mm to 18 mm, and the spacing between the self-stressed transverse reinforcements is 50 cm to 70 cm.

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