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Construction method for large scale high-performance cement concrete road panel

A technology of cement concrete and construction methods, which can be applied to cohesive pavement paved on site, roads, roads, etc., can solve the problems of concrete pavement slab fracture, breakage, damage, etc., reduce daily maintenance costs, reduce the probability of damage, The effect of increasing the safety factor

Inactive Publication Date: 2004-08-18
CHINA AIRPORT CONSTR 2ND GENERAL TEAM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The main reasons for the damage of the cement concrete pavement during use are: (1) the force of the load during the use of the concrete, the warping stress caused by temperature changes, the deformation stress caused by thermal expansion and contraction, the frictional resistance of the foundation, The resultant force of deformation stress and other acting forces caused by water or foreign matter entering the side seam is greater than the compressive or flexural strength of the concrete itself, resulting in damage phenomena such as edge drop, hole, and fracture of the concrete pavement slab; (2) due to the The side joints of the panel have not been properly processed, the joints have not been cut in time, the vibration of the sides is not firm, and the slurry at the side joints is not full when the concrete is used as the surface, which causes the edge to fall off or even break; (3) the road is caused by the subsidence of the foundation The tensile stress in the local area of ​​the surface concrete increases sharply, resulting in concrete failure, and the frost heaving effect after the foundation seepage causes the pavement concrete to break; (4) The reflective cracks of the semi-rigid foundation and rigid foundation cause the fracture of the concrete pavement slab
(5) The side joints are damaged during the concrete construction process due to construction techniques such as running the mold, vibrating, working the surface, and cutting the seams; (6) The side joints of the cement concrete pavement are under load during use Because its ability to transmit load is poor compared to other parts of the road panel, stress concentration is caused at the side seam, which makes the side seam more vulnerable to damage; because the side seam is easy to enter foreign matter and water seepage, it will suffer from thermal expansion and contraction and freezing prone to breakage under the action of swelling
The damage of the side seam will not only directly lead to the driving comfort and driving safety of the cement concrete pavement, but also cause the defects of the cement concrete pavement. After further development, it will cause the foundation to sink and the slab to break, which will lead to cement concrete pavement. The channel panel loses its function partially or completely
Due to the difficulty in the construction of large-size cement concrete pavement slabs, it is easy to cause unqualified quality. Therefore, the current design specifications stipulate that the size of the regular slabs of plain cement concrete pavement slabs shall not exceed 5M×5M, and the transverse dimension shall not exceed 5M. Therefore, in my country The size of the sub-warehouses of the existing airports and roads has been staying at about 4-5M. Due to the many weak links caused by the small cracks of the boards, the service life of the airports and roads is relatively short

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] Embodiment 1: in the present embodiment, the horizontal sub-store size of the pavement concrete slab is determined to be 6 meters and the longitudinal dimension is determined to be 10 meters;

[0008] 1. The requirements of various materials in concrete are as follows

[0009] Ordinary Portland cement is used as cement. Tricalcium aluminate (C 3 A) content (C in cement clinker 3 The content of A) is controlled within 5%, tetracalcium aluminoferrite (C 4 AF) content (C in cement clinker 4 The content of AF) is greater than 16%, the alkali content is less than 0.6%, and the factory temperature of cement is lower than 60°C. The remaining standards shall comply with the technical requirements of Portland cement and ordinary Portland cement (GB175-92).

[0010] The crushed stones should meet the requirements of JGJ53-1992 quality standard for crushed stones used in ordinary concrete, the evaluation of alkali-aggregate reaction should be carried out, and non-alkali activ...

Embodiment approach

[0017] (1) First of all, the base layer should be treated well. The base layer should be made of fly ash stone base, that is, cement, fly ash, and gravel should be used as the base layer, and the cement, fly ash, and gravel used should meet the requirements and standards mentioned above. The basic level should meet the following indicators:

[0018] ①Compactness ≥ 97%;

[0019] ② Flatness ≤ 10mm;

[0020] ③Elevation -10mm~+5mm;

[0021] ④ Pavement thickness error ± 10%;

[0022] ⑤7d unconfined compressive strength ≥ 3.0MPa;

[0023] ⑥The width is not less than the design value;

[0024] ⑦ The composite elastic modulus of the top surface of the base layer is ≥120MPa;

[0025] ⑧ No large cracks or breaks. If there are large cracks or breaks, they should be treated with asphalt felt to avoid reflection cracks.

[0026] 2. Release sample piles / bounce ink lines on the prepared base;

[0027] 3. Support the formwork according to the sample pile and the ink line:

[0028] (1)...

Embodiment 2

[0063] Embodiment 2: in the present embodiment, the horizontal dimension of the pavement concrete slab is 5 meters and the longitudinal dimension is 8 meters;

[0064] Concrete mix ratio example Table 1b

[0065] Table 1b

[0066] Mix ratio (Kg)

[0067] The selection criteria of materials are the same as in Example 1. In this embodiment, the construction temperature is 10-20°C, and the allowable maximum time for the concrete mixture to be paved, vibrated, and surface-made (without napping) from the discharge of the mixer is 90 minutes, and the wind speed is 16Km / h. The difference between the concrete temperature and the atmospheric temperature is 5.6°C, and the evaporation rate is limited to 0.5Kg / m 2 h, the relative humidity is 80, and the limit temperature of plastic shrinkage and cracking of concrete is 37.8°C. When extracting pulp and making surface, use three times of plastering method, first with non-metallic material once, then with metal material twice, O...

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Abstract

The construction method of large size cement concrete road slab includes connecting formwork without crack in the joints, using blended concrete material with fiber, water reducing agent or swelling agent, completing spreading, vibrating and other steps at 5-38 deg.c within 60-120 min after the concrete material is discharged from the stirrer, spreading in wind speed less than 2 m / s and relative humidity higher than 60 %, adopting twice vibrating, face work for 3-4 times, twice crack cutting, and spraying film and adding protecting layer for curing after surface grain treatment. The said construction method can ensure the road quality, reduce side cracks between slabs, reduce the damage of road slabs caused by foreign matter and water, lower the road maintaining cost and prolong the service life of road.

Description

technical field [0001] The invention belongs to the construction method of airports or roads, and in particular relates to the construction method of the cement concrete road slab with a bin size larger than 5M×5M Background technique [0002] The main reasons for the damage of the cement concrete pavement during use are: (1) the force of the load during the use of the concrete, the warping stress caused by temperature changes, the deformation stress caused by thermal expansion and contraction, the frictional resistance of the foundation, The resultant force of deformation stress and other acting forces caused by water or foreign matter entering the side seam is greater than the compressive or flexural strength of the concrete itself, resulting in damage phenomena such as edge drop, hole, and fracture of the concrete pavement slab; (2) due to the The side joints of the panel have not been properly processed, the joints have not been cut in time, the vibration of the sides is...

Claims

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Application Information

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IPC IPC(8): E01C7/14
Inventor 杨传喜左汉明刘持友杜晨曦
Owner CHINA AIRPORT CONSTR 2ND GENERAL TEAM
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