Inspection and evaluation of anti-corrosion coatin

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Inspection and evaluation of anticorrosive coating of steel structures in service

inspection and evaluation of anticorrosive coating of steel structures in service

March 4, 2020

0 Introduction since the 1990s, when it is expected to be completed and put into operation in 2020, with the rapid development of science and technology and the continuous investment in national infrastructure, China has formed a huge industrial chain of building steel structures. Take Shanghai as an example only. From the construction of Shanghai center, Shanghai Disneyland and Xinggang International Center, the highest "twin towers" in Shanghai, to Shanghai Hongqiao comprehensive transportation hub, Pudong International Airport and the China Pavilion of Shanghai WorldExpo, representative buildings emerge in endlessly

in order to avoid the corrosion damage of the building steel structure by the atmospheric environment during service, the coating is often used to protect the building steel structure coating. In the existing engineering cases, it has been proved that coating is one of the most economical and effective methods to protect building steel structures. In general, the effective protection period provided by the coating system is often shorter than the service life of the building steel structure. Therefore, in the planning jc/t547 (2) 005 ceramic tile adhesive and the design stage, the interested parties must consider the possibility of its maintenance and reconstruction

at present, many coatings of building steel structures have different degrees of failure during service. However, most of the building steel structures have not established perfect post maintenance data during their service. Early steel structure construction units are often not later maintenance/repair units, resulting in the lack of professional planning and guidance before maintenance. During the maintenance, there will often be incompatibility between the maintenance coating and the old coating, and both sides of the substrate surface treatment cooperation will unswervingly implement the sustainable development and operation strategy in the production field without professional and normative requirements, which will lead to premature failure of the later maintenance coating

therefore, it is necessary to study how to regularly inspect and evaluate the coating of building steel structures in order to formulate maintenance plans

1 experimental part

1.1 determination of corrosive environment

according to ISO "color parallel interface is often used to connect the corrosion protection of extraction equipment (such as printers) paint and varnish protective paint system on steel structure part II Classification of corrosive environment", the environment of building steel structure is mainly listed in Table 1

Table 1 Classification of corrosive environment

1.2 division of engineering area

collect and record engineering data (including construction records, project drawings, construction supporting facilities, etc.)

after referring to the project drawings and on-site preliminary observation, understand the structural distribution and construction area of the whole steel structure project, and divide the project into several areas. Such as top, column, main structure, walking platform, handrail, etc

1.3 on site coating appearance inspection

according to the requirements of relevant standards and specifications, the coating appearance quality of the project is inspected, mainly including the rating of peeling, cracking, blistering and rust (see Table 2). Other defects can be recorded and evaluated at the same time for auxiliary reference. During the on-site inspection, the location, degree and percentage of the main damage phenomenon of the coating will be described, recorded, and analyzed to determine its failure and aging conditions and causes

Table 2 rating of peeling, cracking, blistering and corrosion

1.4 on site coating performance inspection

spot check the coating performance of the project, mainly the measurement of coating thickness

measure the coating thickness by electronic dry film thickness gauge and analyze the cause of coating failure. For example, the film thickness is too thick to crack or the coating film thickness does not meet the design requirements and early corrosion occurs

2 on site evaluation and discussion of steel structure

in May 2019, the on-site inspection and evaluation of the anti-corrosion coating of building steel structure was carried out in the phase I plant of Hangxiao Steel Structure Co., Ltd

2.1 project background

Table 3 project background

2.2 site evaluation report

according to the project background (Table 3), the site evaluation part is the internal column beam, see Table 4 and figure 1 for details

Table 4 on site evaluation report of internal column and beam

Figure 1 on site picture

after on-site evaluation, the corrosion degree is relatively light. It is recommended that the corroded area be polished to the substrate, grade ST3, and the original coating be pulled out of the breach. Pay attention to cleaning before treatment, and it is recommended to wash with high-pressure water. The plant is an open area. Pay attention to the temperature and humidity during construction

3 conclusion

through the on-site inspection and evaluation of building steel structures, the main factors that reflect the corrosion degree of the anti-corrosion coating of steel structures are: blistering, peeling, cracking, rust. The rating of these defects can directly reflect the "health" of the coating of the steel structure part or the whole, so as to effectively maintain them and carry out appropriate maintenance plans

references (omitted)

for details, please refer to coating and protection, No. 12, 2019

author/Miao CE, Hu Xiaozhen

(Shanghai Jianke Inspection Co., Ltd./national construction engineering material quality supervision and Inspection Center, Shanghai 201108)

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