Construction technology which uses formwork lining to reduce application period of coating
Author:Runshang custom service    Time:2015-02-02 10:22:01   


Department level excellent construction method in 2012


Paste formwork lining

On the left is concrete corresponding to formwork lining and on the right is concrete corresponding to normal steel formwork.


Water enclosing facilities and pumping equipment are used to create anhydrous coating environment.

According to Specifications of Corrosion Prevention Technical Specifications for Concrete Structures of Marine Harbor Engineering (JTJ 275-2000), in order to ensure adhesive force and service life of anticorrosive coating, maintenance period of concrete member shall be no less than 28 days generally and moisture content shall be less than 6%. Before coating, special diluent shall be used to clean oil contamination and release agent on the surface of structure, dust in crack and hole shall be washed away and water stain on the surface of concrete shall be dried so as to keep concrete surface dry. After epoxy seal primer construction, visible air hole and flaw shall be repaired by special epoxy putty so as to ensure smooth and continuity of coating. Putty shall combine with coating surface well, which is good for solid adhesion with structure foundation plane and good compatibility with coating. Conduct maintenance for 7 days after coating construction and then coating performance test can be carried out.

Paste controlled permeable formwork lining on internal wall of steel formwork or wood formwork. Eliminate bubble, bleeding, sand line and cavity on structure surface, which can exempt the working procedure of putty leveling before concrete coating. This can improve concrete surface spring back strength significantly in early stage, reduce moisture content of surface concrete, reduce concrete age sharply during coating, accelerate turnaround speed of water enclosing facilities, and reduce pumping time in the cofferdam and save capital investment. Disassembly, polish of steel or wood formwork and paste of formwork cloth can be conducted ashore. Paste controlled permeable formwork lining on internal wall of steel formwork or wood formwork can improve surface concrete quality in early stage, reduce surface flaw and reduce coating period. It is successfully applied in Qingdao Bay Bridge project for 350,000 m2.

Use concrete in formwork lining in detection in parameters of appearance, alkali resistance and adhesive strength of coating in ages of 14d, 18d and 21d and the results conform to provisions and requirements specified in Specifications of Corrosion Prevention Technical Specifications for Concrete Structures of Marine Harbor Engineering ( JTJ 275-2000). After comprehensive consideration of several factors in practical construction process, it is finally confirmed that 10d is shorten than that specified in specification when concrete age reaches 18d.

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