Waterproof board

Release time: [2017-08-22 02:28:01]    Views:125


Waterproof Board

 


Waterproof board is also known as geomembrane with thickness no less than 0.8mm. Geomembrane is <0.8mm. Waterproof board is a impervious material based on polymer, including homogeneous waterproof board and composite waterproof board.
Its main function is to prevent the leakage of liquid and gas evaporation.
Raw materials include: low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene / vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), ethylene vinyl acetate Asphalt (ECB) and so on.
The role of geomembrane in rock projects is mainly for seepage and isolation. But also it plays a role of strengthening and protection. It mainly used in: earth and rock dam, rock fill dam, masonry dam, concrete dam, tailing dam, sewage reservoir dam, channel, reservoir and other projects seepage control; subway, basement and tunnel lining; highway railway foundation anti-seepage; sanitary landfill with filament geotextile, bentonite waterproof blanket and other geotextile materials application, etc.
Code for construction of waterproof board
1. Preparation before laying:
1.1 Foundation treatment: cleaning laying layer with smooth surface, solid soil, not rugged and no cracks, etc., no sharp objects, stones, wire, sticks; seepage within the turf and roots should be cleared; spraying herbicide for weed.
1.2 Laying small particle size of the sand or clay layer as a protective layer no be less than 30 cm on the interface
2. Paving method:
2.1 Laying along a certain direction, and do not pull too tight, with a certain amount of stretching to adapt to the matrix deformation.
2.2 Adjust the direction of each unit in order to facilitate the welding of two units when laying waterproof board 
2.3 After the laying of the waterproof board, use sand bags to suppress to prevent the impact of sand for next step of edge welding.
3. Watertight welding. Seam treatment is the key procedure for construction. Generally using thermal welding method, PE film phase surface heat treatment to melt the surface, and then press them into one.
3.1 For the finished laying of waterproof board, there should be no oil, water, dust and so on the seam of the edge.
3.2 Before welding, adjust each side of the two PE films with a certain width of 6 ~ 8 cm, with no wrinkles.
3.3 Use a special welding machine for welding.
4. Welding quality inspection:
4.1 The test methods include inflatable and indoor test, also spark test or ultrasonic detection.
4.2 The testing equipment is air pressure detector and vacuum detector.
4.3 Weld quality requirements:
4.3.1 Inflate the two seams. Inflation pressure is 0.15-0.2MPa for length of 30-60 mm welded seam. It is qualified if the pressure is not significantly reduced in 1-5min.
4.3.2 For single weld and T-shaped joints and repaired knots, applying 50 cm × 50 cm grid for vacuum testing with pressure no less than 0.005MPa. It is qualified if no soap bubbles in 30 seconds.
4.3.3 Indoor test. Weld tensile strength should be greater than the base metal strength.
4.3.4 Quality inspection should be carried out with the construction progress.