Quality inspection of bridge deck pavement engineering?

Keywords: bridge deck pavement quality inspection scheme

I. Overview of the Project

(1) Project Overview

The total length of the elevated road (Phase I) project is about 30km, the width of the standard section is 1 1.25m, and the total thickness of the asphalt pavement of the elevated road (Phase I) project is 90MM, which is paved in two layers. The lower layer is AC-20C asphalt mixture with a thickness of 50MM, and the upper layer is SMA- 13 asphalt.

(II) Compilation basis

(1) Test Code for Asphalt and Asphalt Mixture in Highway Engineering JTJ052-2000

(2)JTG highway engineering aggregate test specification E42-2005

(3) Code for Field Inspection of Highway Subgrade and Pavement JTJ059-95

(4) Technical Specification for Highway Asphalt Pavement Construction JTG F40-2004

(5) Code for Construction and Acceptance of Asphalt Pavement (GB 50092-96)

Second, the asphalt mixture road (bridge) paving quality status and quality inspection points

Road (bridge) surface is also called roadway surface, or bridge deck protection layer, which is the direct part of the wheel. Its function is to prevent the vehicle tires from directly wearing the carriageway slab as a part of the main beam, to prevent the main beam from being eroded by rain, and to some extent, to disperse the concentrated load of the vehicle wheel weight. Therefore, bridge deck pavement requires rutting resistance, driving comfort, sliding resistance, wear resistance, low temperature crack resistance, impermeability and good rigidity.

With the further expansion of the scale of urban infrastructure construction in our city, the quality of road construction in our city has achieved a qualitative leap and reached a new level through the effective improvement of construction technology by construction units, the strengthening of process quality control and the effective supervision of local construction administrative departments. But with

With the full liberalization of the construction market, the competition among construction enterprises has intensified. In order to reduce costs, the quality of projects has declined from time to time. The newly paved asphalt pavement will be damaged to varying degrees in a short time, and the pavement damage is mainly reflected in transverse cracks, cracks, rutting, subsidence, loose peeling and so on. Our province is located in 1-4 area, which is hot in summer and rainy in winter. After a rainy season, asphalt pavement is easy to be damaged to varying degrees, such as potholes, looseness, falling particles and even potholes, and white patches appear on black brand-new pavement, which happens from time to time around us. Therefore, the water damage of asphalt pavement should be the focus of our prevention and control.

The durability of asphalt pavement that meets the structural requirements is affected by two main indexes, namely, the design and compaction of mixture. SMA is a kind of asphalt mixture with discontinuous gradation, which can be summarized as "three more and one less": more coarse aggregate, more mineral aggregate, more asphalt binder, less fine aggregate, fiber reinforcement and high material requirements. The test shows that the void ratio of SMA mixture is very small, almost impermeable to water, and the mixture is little affected by water. In addition, the water stability of SMA mixture is greatly improved due to the good adhesion between cement and aggregate. However, only under the premise of an ideal mixture ratio and construction technology can we achieve such a good road effect, otherwise it will be difficult to turn the good road effect into reality.

Third, the quality inspection plan at each stage

(a) the mix design verification stage (before construction)

Excellent mixture ratio is the premise to ensure the quality of engineering construction. The asphalt mixture ratio provided by each mixing station (each mixer) shall be verified by the target and production mixture ratio (each mixing station shall verify the production mixture ratio).

1, the technical indicators and testing frequency of raw materials in the mixture ratio verification, and (3) the normal production and construction stage.

1, raw material testing technical requirements and testing frequency

The quality of raw materials is the basic condition to ensure the quality of asphalt mixture. In order to ensure the quality of raw materials is balanced and stable, and avoid the quality difference caused by different procurement channels of raw materials and the cost saving by the construction unit, raw materials used in Qinglong and Niutang must be tested for various indicators before entering the site, and can only be used after passing the test. At the same time, random sampling inspection is carried out according to the quality stability of raw materials in each mixing station to ensure that the quality of raw materials is effectively controlled in the construction process.

Quality inspection of raw materials and

(4) Pavement construction process and completion acceptance stage

Quality inspection of asphalt pavement is a scientific evaluation of engineering quality and an important way to guide the next stage of asphalt pavement construction. Compaction is one of the most important factors affecting the durability of asphalt pavement. Therefore, it is necessary to strengthen the detection of compaction index of mixture after paving and molding, and detect the compaction degree of two-layer asphalt mixture in layers. For the holes left by pavement compactness and thickness detection, we will clean up the residues in the holes in time. The accumulated water is drained with cotton yarn, and the lower layer is filled with plain concrete. The upper layer is filled with fine-grained asphalt mixture or asphalt mixture with the same proportion, and compacted with a small hammer to ensure the compactness and integrity of the pavement. In this project, the upper asphalt pavement is SMA- 13 mixture. SMA is a brand-new asphalt mixture, and the temperature has a significant influence on it. When the temperature is lower than the specified temperature, the compactness of the pavement will be lower and the void ratio will be larger, which will bring serious adverse consequences to the road performance of asphalt pavement. SMA asphalt mixture

The main measure of water stability is to prevent water erosion, and the degree of water seepage depends largely on porosity and mineral aggregate gradation. If the porosity is small, the mixture is less affected by water. Therefore, the permeability test should be carried out on paved and rolled sections. This can visually test the quality of asphalt mixture rolling and verify whether the void ratio is up to standard. A journey of a thousand miles begins with a single step, and the surface function of asphalt pavement is also a very important link. In addition to the properties of aggregate itself, surface structure and smoothness are key factors. Therefore, in order to test the anti-skid performance and driving performance of the pavement, it is necessary to test the structural depth and smoothness of the formed pavement. In the process of construction, the thickness of pavement should also be strictly controlled. The thickness of asphalt pavement plays a positive role in resisting fatigue damage of pavement and affecting mechanical indexes.

The following table lists the technical indicators and test frequency of each test:

Note: 1, the values in brackets are SMA pavement requirements;

2, pavement permeability coefficient is not more than 50mL/min (SMA pavement) and 60 mL/min (ordinary asphalt concrete pavement).

Index, specification index for pavement permeability coefficient is not more than 200mL/min (SMA pavement) and 300 mL/min (ordinary asphalt concrete pavement);

3. Compaction (%) of the upper layer: Mahalanobis density ≥ 98% 4 ~ 97%; Lower layer: Mahalanobis density ≥ 98% and 4 ~ 97% is the recommended design index. The specification index is 96% (98%) of the laboratory standard density; 92% (94%) of the maximum theoretical density; 98% (99%) of the density of the test section. , maximum theoretical density 9, maximum theoretical density 9

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