Compared with the steel formwork, the wooden circular column formwork mainly performs better in the severe cold temperature construction site. The basic thermal insulation method is generally to seal the thermal insulation material in the middle of the I-shaped beam of the circular column formwork, and use the heat storage method to maintain the concrete cylinder. Common thermal insulation materials include plastic film, laminated glass wool blanket, quilt and so on. The cold resistance requirements should be considered in the formwork demolition work of winter construction measures. The compressive strength of the demolition plate of the column mold is above 2.5mpa. In addition to ensuring the actual effect of the mold, the demolition can be moderately late, but the concrete must be cooled to 6 Disassemble after the temperature falls below, considering the actual effect of heat insulation. When disassembling the formwork, the galvanized steel strip of the supporting facilities must be disassembled first. Because the circular column formwork adopts the convex groove design scheme, a gap will pop up after the steel chain is dismantled, and the disassembly work is becoming very easy. In the insulation and maintenance work, different raw materials should be selected as covering measures according to different average temperature standards. Since the temperature difference between the concrete and the external natural environment should be within 15 degrees, when the temperature difference is between 10-15 degrees, you can choose a quilt with a thickness of 50 mm. When the temperature is quite high, you can choose a plastic film. It is to consider that the compressive strength of the concrete cylinder meets the critical value of compressive strength after considering the heat storage of the concrete to zero degrees.
After the circular column formwork is poured, the cover and maintenance work should be carried out immediately to avoid the loss of heat. The winter construction measures should not be poured and maintained when the temperature is below zero. The circular column formwork for wooden engineering construction immediately jeopardizes the actual effect of cylinder ejection after the glue is opened, the frequency of continuous use of the formwork, the project progress, and the increase in project costs. So what is going on when the glue is opened? Moisture absorption; long-term When placed in a damp and cold natural environment, or after being exposed to rain, water seeps into the inner layer of the circular column formwork, which causes the template to absorb moisture and swell, which is very easy to cause peeling. Insufficient amount of sizing; a very important step in the manufacturing stage is to sizing the core board. If the amount of sizing is insufficient or the sizing is not evenly balanced, the glue will appear in some areas after the finished product.
Glue quality is poor; some manufacturers purchase fake and inferior glues of high quality and low price in order to save product costs. There is insufficient glue cooperation and poor compressive strength. The formwork will open up after three applications. Blockboard has a high water content; the core board selects a whole double board, and the miscellaneous wood and manchurian ash are laid in a cross pattern. The width of the core board is large and the joints are few. The finished products have high compressive strength. If the moisture content of the blockboard is high, the moisture cannot be sufficiently volatilized during the ultra-high pressure production process, and the residual moisture in the circular column formwork exceeds the standard, and the glue will be opened in the middle and late application process. Unqualified working pressure; unqualified working pressure is also very prone to open glue. Excessive work pressure can easily cause blistering and blistering, and work pressure is higher than today. In addition, the quality of abrasive tools endangers the actual effect of pressing and the standard level of finished products. The pressing time is short; all the normal pressing time of circular column formwork is 40 minutes. If the manufacturer reduces the pressing time in order to rush to manufacture, the formwork will be very easy to open the glue.
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