- Civil Engineering Water-shielding Materials
Disposal sites and contaminated soil
Final disposal site for waste materials
Final disposal sites require long-term water-shielding performance from the start of service to the completion of the landfill, and ultimately until the landfill waste materials have stabilized. Thus, as designated by Japan's Ministry of Health, Labour and Welfare's performance guidelines for "waterproofing construction requiring planned water-shielding effectiveness," it is necessary to select the appropriate water-shielding sheet, appropriate design specifications, installation procedures, and maintenance schedule according to the environmental and usage conditions of each disposal site. With our wide selection of various types of sheets and protective materials, and established record of design and installation work, Mitsuboshi Belting Ltd. is able to provide the technical know-how to answer diversified needs.
Quality control system
Upon laying each water-shielding sheet on-site, water leakage may occur if the sheets are not properly bonded together. Bonding methods can vary for each type of sheet, including thermal bonding, and the use of bonding adhesives or tapes.
Bonding using automated bonding machine
MIZUSHEET FPA, DISPOLINER and similar products are mostly bonded together using an automated bonding machine that utilizes a double-seam (double-track) bond. The bonding machine's temperature, speed, and pressure settings are determined based on the weather conditions and temperature of the sheet when bonding.
Bonding using extrusion bonding machine
For the above-mentioned sheets, bonding a three-layer area or an area where it is difficult to use an automated bonding machine, an extrusion bonding machine is used. An extruded bond is when a temporary bond of approximately 50mm is created using a manually controlled bonding machine and then a bonding rope made of the same material is melted and overlaid onto the edge of the bonded area.
Bonding using bonding adhesives and tapes
MIZUSHEET and MIZUSHEET S are bonded together by applying a bonding adhesive or bonding tape to the bonding area.
Water-shielding sheet bonding integrity flow
All sheet s areas bonded on-site are subject to testing. Testing methods include air pressure testing, vacuum testing, and test bar insertion testing.
Air pressure test
This testing method involves applying pressure to the areas of the water-shielding sheets that were bonded on-site (generally areas bonded using an automated bonding machine). A device where insertion needles are linked to an air pump delivers air between the two seams, pressure is applied, and a pressure drop of less than 20% per minute should be observed.
This testing method involves placing the area subjected to extrusion bonding or the three-layer area of the water-shielding sheet in a vacuum box (a clear case device with a suction machine) and reducing pressure. Soapy water is applied to the testing area and the pass/fail determination is made by observing the presence of bubbles.
Test bar insertion test
For bonded areas that cannot be tested using the aforementioned methods, a test bar head (such as a flat-head screwdriver with a rounded head) is pressed against the area bonded on-site, moved alongside the bonded area, inserted, and detachment is tested.