Precast Fabricated Comprehensive Concrete Box Culvert Gallery

2017-09-05 22:44:46 grant 3

Precast Fabricated Comprehensive Concrete Box Culvert Gallery

Production process of precast concrete box culvert is worked out by deep discussion of many  precast concrete product factories . Faced with hot situation of precast concrete box culverts, this article is carefully presented here. 8000KM construction of concrete box culvert gallery has been a huge field.

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1. Concrete box culvert is produced according toprovided by concrete box culvert form manufacturer and other designing institutes .
2.  Precast Fabricated Concrete Box Culverts has these types: single bin, double bin,multi-bin concrete box culverts, reinforced concrete box culverts .
3. Precast fabricated concrete box culverts specification:(L*W*H,Thickness mm) 2000/1500/2000/160mm, 2000/2000/2000/180 single hole top botttom 200mm, 3000/2600/2500 top bottom 300mm etc.
4.  Production technology of concrete box culvert from attached with concrete vibrator. Production effects can reach quality standard fully but bottom plate inner surface is not very good. Because the limit of quantites of grout vent in the bottom plate, extra air can't be discharged from bottom plate thus result in pitted surface, concave pit and water ditch etc which require manul repair again.

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5. Curing method of concrete box culvert is covered steam curing cover or curing chamber on ground with steam .After production,  static stop of 0.5~1hour later the temperature will go high, the heating rate ≤20℃/h, Max. temperature can't more than 60℃/h. Heating stage is 3 hours and constant temperature stage is 4 hours. Cooling is natual way.

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6. Joint type is tongue and groove spigot type,  adhesive tape is sticked on the inner end surface of spigot . The effect is very good.
7. concrete box culverts connection is tensioned by steel  strand.
8. Raw materials of fabricated concrete box culverts:
cement: P.O 42.5 ordinary Portland cement.
Sand: local river sand with earth 2.3% mixed; 2.5-2.8.
Stone: diameter 5-20mm with earth 0.4% mixed, stone powder 4.6%, performance density 2792kg/m3, elonged particles content 8.7%, porosity is 42%.
Additive : FDN-Z High efficiency slushing agent, mixing amount 0.85%.
The quality will be best if the raw materials are same with above requirement .
9. Concrete box culvert steel famework is bended and cut manually, assembled manually and welding . Productivity is low and work strength is high.
10. concrete strength is C40. slump will be controlled with 60-80mm, water and cement ratio is 0.42. With forced planetary concrete mixer and computer control weight.
11. Apperance Inspection

cda6d8aa58a54e9ea6db7c9a3e2fc871_th.pngBox culvert innner and outer surface must be smooth and dense. No cracks, honeycomb, pitted surface, air hole, water channel, sand and stone exposing etc.
Spigot joint end surface is smooth and not angel lossing. No cracks and reinforcement exposing.
Side wall embedded bolts should be fixed and in one line.
Tensioing holes should be same size and very arranged properly.
12. Single Layer or Double Layer stacking. Truck transportion.





 


TAG:  concrete box culvert  comprehensive concrete culvert