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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., which can solve the problems of concrete pavement slab fracture, fracture, pavement concrete fracture, etc., to reduce daily maintenance costs and reduce damage chance, the effect of prolonging the service life

Inactive Publication Date: 2007-10-03
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

[0029] Embodiment 1: In this embodiment, the horizontal dimension of the concrete slab of the road surface is set at 6 meters, and the longitudinal dimension is set at 10 meters;

[0030] 1. The requirements for various materials in concrete are as follows

[0031] The cement uses ordinary Portland cement. Tricalcium aluminate (C 3 A) content (C in cement clinker 3 The content of A) is controlled within 5%, tetracalcium iron aluminate (C 4 AF) content (C in cement clinker 4 The AF content) is greater than 16%, the alkali content is less than 0.6%, and the cement factory temperature is lower than 60°C. The other standards should meet the requirements of Portland cement and ordinary Portland cement technical requirements (GB175-92).

[0032] The crushed stone shall meet the requirements of JGJ53-1992 crushed stone quality standard for ordinary concrete, the alkali aggregate reaction shall be evaluated, and non-alkali active materials shall be selected.

[0033] The medium-coarse san...

Embodiment approach

[0039] (1) First, handle the base layer. The base layer should be lime limestone base layer, that is, cement, fly ash, and crushed stone are used as the base layer, and the cement, fly ash, and crushed stone used should meet the requirements and standards described above. The basic level should meet the following indicators:

[0040] ①Compact degree ≥97%;

[0041] ②Flatness ≤10mm;

[0042] ③The elevation is -10mm~+5mm;

[0043] ④The error of road surface thickness is ±10%;

[0044] ⑤ 7d unconfined compressive strength ≥3.0MPa;

[0045]⑥The width is not less than the design value;

[0046] ⑦The composite elastic modulus of the top surface of the base layer is ≥120MPa;

[0047] ⑧There are no big cracks or breaks. If there are big cracks or breaks, asphalt felt should be used for treatment to avoid reflection cracks.

[0048] 2. Lay out sample piles and pop up the ink line on the completed base layer;

[0049] 3. Support the template according to the sample pile and ink line:

[0050...

Embodiment 2

[0085] Embodiment 2: In this embodiment, the horizontal dimension of the pavement concrete slab is 5 meters, and the longitudinal dimension is 8 meters;

[0086] Concrete mix ratio such as Table 1b

[0087] Table 1b

[0088] Mixing ratio (Kg)

[0089] The selection criteria of the materials are the same as in Example 1. In this example, the construction temperature is 10-20℃, and the allowable maximum time for the concrete mixture from the mixer to paving, vibrating, and working (not including napping) is For 90 minutes, when the wind speed is 16Km / h, the difference between the concrete temperature and the atmospheric temperature is 5.6℃, and the evaporation rate is limited to 0.5Kg / m 2 ·When h, the relative humidity is 80%, and the limit temperature of concrete plastic shrinkage and cracking is 37.8℃. The three-pass screed method is used when the slurry is lifted and the surface is applied. , Other practical methods and conditions are the same as in Example 1.

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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 a construction method for airports or roads, and particularly relates to a construction method for cement concrete pavement slabs with a sub-silo size greater than 5M×5M. Background technique [0002] The main reasons for the damage of cement concrete pavement during use are: (1) The force of the load during use of the concrete, the warping stress caused by temperature changes, the deformation stress caused by thermal expansion and contraction, the friction resistance of the foundation, The combined force of deformation stress and other forces caused by water or foreign matter in the edge seam is greater than the compressive or flexural strength of the concrete itself, causing the concrete pavement panel to fall off edges, corners, holes and breaks; (2) due to the road surface The side seam of the panel is not properly processed, the cutting seam is not timely, the edge is not vibrated, and the slurry at the side seam is not full wh...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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