IPM Blackline Geomembranes

Transcription

1 IPM Blackline Geomembranes Icopal OY Läntinen teollisuuskatu 10 FIN Espoo, FINLAND Tel Fax Web

2 Content: CONTENT: INTRODUCTION: GEOMEMBRANES: HISTORY OF PLASTIC FOR GEOMEMBRANES: ADVANTAGES OF LDPE: SELECTION OF GEOMEMBRANE LDPE VS. HDPE: Physical demands: Elongation at break: Chemical resistance: Biological resistance: Installation of liner: CCT test system: THE MONARFLEX GEOMEMBRANES: GEOMEMBRANES VS. GEOTEXTILES: RESISTANCE TO PUNCTURE: TEST RESULTS: QUESTIONNAIRE GEOMEMBRANE INSTALLATION: HOW TO ESTIMATE CONSUMPTION OF GEOMEMBRANE: LONGITUDINAL SECTION: CROSS SECTION: NET AREA GEOMEMBRANE: WELDING: SUPPLEMENT FOR HOT-AIR WELDING AUTOMATIC EQUIPMENT: MACHINERY AND EQUIPMENT: WELDING WITH HAND-HELD EQUIPMENT: WELDING WITH AUTOMATIC EQUIPMENT: INSTALLATION OF MONARFLEX S GEOMEMBRANE: THE EXCAVATION: PROTECTIVE LAYER/DRAIN LAYER: UNROLLING OF THE GEOMEMBRANE (ALSO SEE DRAWING PAGE 23): UNFOLDING OF THE GEOMEMBRANE: ANCHORING ALONG THE EDGES: TRAFFIC ON UNCOVERED MEMBRANE: STARTING THE LAYING OF E.G. DOMESTIC WASTE: INSTALLATION IN HOT WEATHER: INSTALLATION HINTS: GEOMEMBRANE INSTALLATION DETAILS:...26

3 1. Introduction: Since time began clean water has been necessary to support life, and existence of water in our eco-system has provided a bases for the development of organic life. In Italy during the Roman Times the engineers constructed aqueducts and cisterns for transporting and storing drinking water. In the same period construction of sewers for collection and transporting of polluted water from homes and factories took place. The explosion in population during the last 2000 years combined with the industrialisation during the last century has grown in a completely unexpected pace. The population and industrial expansion is today a growing threat to our environment and it is more important than ever that we protect our watercourses and maintain our eco-system. It is our hope that this manual, and the products described therein can be of assistance in guarding our national resources, enabling further generations to exist in a healthy and well-balanced environment.

4 2. Geomembranes: 2.1. History of plastic for geomembranes: Plastic has become a word of daily use, and covers today a large group of organic nature. The first plastic was developed almost 100 years ago and through developments of the petrochemical industry a vast number of different plastic products have been developed. The present pace of plastic industry however indicates that it is still to be considered a young science as it is constantly developed for new purposes. In the following we will therefore, concentrate on the plastic products used as geomembranes, namely polyethylene and especially LDPE (Low Density Polyethylene), which is the type used for the geomembranes manufactured by MONARFLEX A-S. In the beginning of the 1930 s, ICI in England started researching in the development of Low Density Polyethylene (LDPE). The first commercial product of LDPE, took place in 1938/39. The manufacturing process involved plastification under very high pressure; LDPE is also known as high-pressure polyethylene. In 1950 a new type of polyethylene was produced using low pressure. This process is classed as HDPE (High Density Polyethylene). Both above-mentioned products fall under the category Thermoplastics. LDPE is characterized by being soft and flexible with a density between to g/m 3. HDPE is characterized by being somewhat stiffer and less flexible, with a density between to g/m 3. Later developments have created MDPE (Medium Density polyethylene), which fills the gap between LDPE and HDPE. The main benefits with all these types are that they are casually manufactured into sheets, which can be readily used as geomembranes, plus the extremely good chemical resistance by these polyolefins. Polyethylene is nowadays the most commonly used plastic material with applicators ranging from the thinnest packaging film to highly technological products. Plastic is today accepted as a workhorse in modern society and MONARFLEX A-S has chosen LDPE as the backbone for geomembranes in environmental protection.

5 2.2. Advantages of LDPE: In the manufacturing process of geomembranes, polyethylene is the most common polymer with the following advantages: 1. Relatively easy to manufacture. 2. Good chemical resistance. 3. Good mechanical strength. 4. Long life. 5. Relatively low material cost. The following figures demonstrate the way properties gauge as the density increases from LDPE to HDPE. Physical properties: Rising density: LDPE characteristics: Stiffness: Greater + Hardness: Greater Flexibility: Lower + Cold flexibility: Greater + Resistance to stress cracks: Lower + Resistance to chemicals: Greater As can be seen both types of material are well suited for geomembranes, but LDPE seems to have an advantage. Since 1950, MONARFLEX A-S has been manufacturing plastics, and when development of geomembranes took place in 1972/74 it was from our long experience and very thorough consideration that LDPE was chosen as material for our range of geomembranes. One of the most important reasons for choosing LDPE was simplicity in manufacturing, flexibility in almost any reasonable temperature, good chemical resistance plus experience with LDPE dating almost 50 years back.

6 Since 1974 MONARFLEX A-S has produced and installed millions of square metres of geomembranes in many parts of the world. The manufacturing of MONARFLEX geomembranes is carried out on machinery designed and built by our own company and the joining of the membranes in our factory or in the field is also made by special machinery developed by MONARFLEX A-S. Our company has a large production of specially developed plastic films, to other end uses within the building industry, agriculture, horticulture etc. Experience and know how since 1950 is the backbone of our present standard Selection of geomembrane LDPE Vs. HDPE: When a customer is about to pick out a geomembrane, the customer is in some cases confronted with choosing between HDPE and LDPE membranes. In the following we shall try to illustrate some of the technical factors that are involved in deciding which geomembrane to choose. 1. Physical demands: HDPE will normally have a tensile strength of about N/mm 2 LDPE will normally have a tensile strength of about N/mm 2 (The MONARFLEX Blackline geomembrane have a tensile strength of 16 N/mm 2 ). It is not relevant to choose HDPE because the tensile strength is about the double of LDPE. The main reason to this is that when a geomembrane is installed it is supposed to be free of tension, as it is a common perception between scientists that membrane material is not reliable for a period of years if it is subject to constant tension. 2. Elongation at break: HDPE has normally an elongation at break of about %. LDPE has normally an elongation at break of about %. (The MONARFLEX Blackline membrane has an elongation at break of about 600 %). These values are not of much relevance as in practice you cannot use elongation beyond the yield-point.

7 When plastic materials are tested for breaking strength and elongation at break, a narrow test specimen is cut out and drawn until breakage. When the test material reaches the yield-point, molecular chains are aligned, placing the chains parallel like strings, thus obtaining extra strength in the direction of traction. On the other hand the cross-links are destroyed, causing a total loss of strength in the transverse direction. If you pay importance to a judgement, the elongation at yield is the only value to practise. HDPE has normally an elongation at yield of about %. LDPE has normally an elongation at yield of above 50 %. (The MONARFLEX Blackline membrane has an elongation at yield of 60 %). 3. Chemical resistance: When dealing with chemical resistance HDPE and LDPE are so closely related the there is practically no difference. In some cases HDPE may have a little advantage. Especially when talking about environmental stress cracking. LDPE will, because of a greater flexibility, not be likely to build up tensions that may cause environmental stress cracking. MONARFLEX s geomembranes are tested for influence an artificial leachate, and neither material nor welding seams shows signs of redacted values. 4. Biological resistance: The Blackline membrane is tested for influence by biological active soil and neither material nor welding showed values of importance. 5. Installation of liner: It is most important for both the quality and for the customer that the lining in a reasonably short time will be installed. HDPE may normally be installed with an amount corresponding to m 2 per day if fair weather. Our procedure with pre-welded sections means that our Blackline membrane can be installed with up to m 2 per day. When working in LDPE it is possible to line and weld down to 0º Celsius (if necessary down to -5º Celsius). It is important that the lining and welding experts are well trained and experienced. MONARFLEX s crew have worked with the MONARFLEX geomembranes for more then 15 years. In connection with the lining of a geomembrane area it is important that control is exercised when the project is handed over. This control should be exercised in co-operation between supplier/lining-crew and customer/adviser.

8 The control should include the membrane area as a whole, the membrane material and the welding seams. Now MONARFLEX A-S can offer a 100 % tightness-control of all welding seams. MONARFLEX A-S has developed the CCT test system making it possible to test all welding also on the site. 6. CCT test system: a) It is practicable on the whole welding length. b) Can be done within reasonable time. c) The welding seam is not to be prepared with soap-solution, that is difficult to remove, thus making it difficult to exercise later repairs. 3. The MONARFLEX geomembranes: As mentioned earlier MONARFLEX A-S utilises the advantages of LDPE for its manufacture of geomembranes. Apart from the flexibility and strength of this raw material a specially formulated Carbon Black masterbatch to counteract the destructive forces contained in sunlight. Continuous quality control of raw materials, additives and thickness is carried out to ensure the uniformity of this high performance product. The MONARFLEX geomembranes are all manufactured in a width of up to 4,00 metre. Types of different MONARFLEX geomembranes: MONARFLEX 500 MONARFLEX 750 BLACKLINE 400 BLACKLINE 500 BLACKLINE 750 BLACKLINE 1000 BLACKLINE ,50 mm thick 0,75 mm thick 0,40 mm thick 0,50 mm thick 0,75 mm thick 1,00 mm thick 1,50 mm thick For further technical information and chemical resistant tables, please refer to specific leaflet/brochure. The MONARFLEX geomembranes are depending of the different types, available in standard sizes of the following:

9 Sizes: 4,00 x 25 m 4,00 x 50 m 4,00 x 75 m 4,00 x 100 m Furthermore it is possible to obtain special extra large roll sizes or even large factory prewelded sheets of geomembranes, please contact us for further information on this. As a rule MONARFLEX geomembranes are joined both in our factory and on site using our own welding equipment. 4. Geomembranes Vs. Geotextiles: 4.1. Resistance to puncture: The principle of protecting a geomembrane with a geotextile is widely accepted and has been used for several years. Previously geomembranes and geotextiles were considered separately. Through close collaboration with manufactures of geotextiles it is now possible to evaluate the combination geomembrane/geotextile as an integral system. The geomembrane is installed to offer resistance to seepage of liquids. The function of the geotextile when installed with geomembrane is to protect the membrane against mechanical damage, ensure that the site welding can take place under clean conditions, and to ventilate gasses and moisture away from the site Test results: The test on POLYFELT geotextile / MONARFLEX geomembrane and POLYFELT geotextile / MONARFLEX BLACKLINE is carried out in accordance with ASTM D751. The test on FIBERTEX geotextile / MONARFLEX BLACKLINE geomembrane is carried out in accordance with FTMS 101c. In both standards the penetrating medium is pyramid shaped. The following table shows the puncture resistance of an LDPE / Geotextile combination compared to HDPE:

10 Product: Measurement: BLACKLINE 1000 (1,00 mm thick): Resistance to puncture 517 N BLACKLINE 1000 / POLYFELT TS 750: Resistance to puncture 2600 N BLACKLINE 1000 / FIBERTEX F3S: Resistance to puncture 2150 N HDPE 2,0 mm geomembrane: Resistance to puncture 1550 N Slight variations between the two test methods can be expected.

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14 5. Questionnaire Geomembrane installation: Job name: Number: Location: Country: Approx. Installation period: End-use: Controlled landfill: Incinerator slags: Sludge deposit: Toxic waste (type): Lagoon (nature): River/stream bed: Other (nature): Drawings: Scales shown: Scales defined m/yards: Contour lines/levels: Boundaries of geomembrane: Length: Width: Length of slope (s): Inclination of slope (s): Details: Drain wells shown: Pipe in/outlets shown: Yes No Pipe through membrane: Pipe through membrane: Dimensions: mm/ø Inclination: Fastening to wood: Yes No Fastening through concrete Yes No Soil condition: Anchorage to top of embankment: Indicate method wated: SAND GRAVEL CLAY ROCKS Grain size of substratum for geomembrane: Grain size and thickness of protective layer on top of geomembrane: Protective layer of geotextile, if any: Other relevant information: 6. How to estimate consumption of Please return this paper to: MONARFLEX A-S, Marielundvej 39 43, DK 2730 Herlev, Copenhagen, Denmark

15 6. How to estimate consumption of geomembrane: When the questionnaire has been completed, it is time to estimate the membrane consumption for the specific job. As shown on the questionnaire you will need length, width and levels of the excavation also, if possible to view of site plan and detailed drawings. For further information on embankments, slope gradients, battening details for structures, dimensions and position of pipe entries and perhaps the most important soil conditions. MONARFLEX s geomembranes supplied in a width of 4 metres, should only be calculated with a 3.8 metre effective width, to compensate for the welding overlap. The example shown on the next page is a rectangular structure; where the estimated quantity of geomembrane is calculated taking into account the welding overlap. It should be noted that the consumption of geomembrane is greater that the surface area of the reservoir.

16 6.1. Longitudinal section: 6.2. Cross section: 6.3. Net area geomembrane: Longitudinal section: Bottom: 16,0 m Slope: 2 x 9,0 m Fastening: 2 x (0,5 + 0,5) m = 36,0 m Cross section: Bottom: 10,0 m Slope: 2 x 9,0 m Fastening: 2 x (0,5 + 0,5) m = 30,0 m Net surface of basin: ( ) x ( ) m = 952 m 2 Net area geomembrane: (30,0 x 36,0) m = 1080 m 2

17 Top view: Number of lengths (rolls): (36/3,8) = 9,47 ~ 9,5 lengths (rolls) Total consumption: (9,5 x 4 x 30) m = 1140 m 2 To overlap/welding uses: 60 m 2 = ca. 5,3 % To welding/fastening uses: = 192 m 2 ~ca. 17%

18 7. Welding: 7.1. Supplement for hot-air welding Automatic equipment: If using a LEISTER model X 84 and model X 10 it is only required 5 to 8 cm for overlap welding. When using LEISTER model X 84 the effective width of a 4,00 metre wide roll of geomembrane can be calculated to 3,90 metre. A welding team must comprise of minimum 2 persons, one to control the width of the overlap, and the other to operate the welding machine. It is advisable for the welding crew to wear clean cotton gloves to avoid contaminating the welding surface of the membrane. It is, in certain cases advisable to place a geotextile or a thin sheet of ordinary plastic film under the welding joint. This will prevent that small particle of sand or grit blocking the transport-pressure rollers. Dust and moisture should be removed from the welding area by using a vacuum cleaner capable of removing both dirt and water. Avoid using a rag to clean the surface of the welding overlap, as this will only press dust and dirt into the micropores of the membrane surface and weaken the weld. It is advisable to load the membrane with 5 to 10 kg. sandbags to prevent wind moving the sections during installation. When welding at an angle of 90 degrees to a precious weld, the top flap must be carefully trimmed, and done so in a flat angle. When starting up, always begin at the lowest point enabling any water to drain away from the welding area. If a job cannot be finished the same day, the edge of the installed membrane can be protected as shown on the sketch. Sketch: Sandbags of 5 to 10 kg. Blackline membrane Thin plastic film

19 On location where automatic weld equipment cannot be used, overlaps are welded with handheld equipment and a pressure roller. The manufacturer indicates a max. weld speed, depending on which model is being used for the specific job. In our experience it should be possible under optimum conditions to install approximately 1000 m 2 per day, using an automatic welder. It is recommended that installation crews are able to perfect their welding technique indoors before being trained on outdoor installation Machinery and equipment: Available for lap welding - Thermoplastic geomembranes: Hand-held blowtorch, electronic controlled, with step less temperature control (20 Cº to 700 Cº) and adjustable air intake (50 to 230 1/min.) Interchangeable nozzles in different width. Pressure rollers, hand held in different models from 40 to 80 mm. Welding machines, self-propelled in 220 or 380 voltage (AC), with or without test channel equipment. Step less temperature control (20 Cº to 700 Cº). Adjustable air intake (400 to 600 1/min.) and speed regulator from 0 to 6 m/min. The welding machine is fitted with double pressure rollers adjustable from 0 to 500 N. Type of welding seams: The joints are made using the following types of lap-weld: Weld without test-channel in width of 30 to 60 mm. Weld with test-channel in width of 30 ( ) or 60 mm ( ). Welding with hot-air equipment: Preparation of the geomembrane The edges of the membranes to be joined must be free from dust, dirt, grease and water. When hand-welding PE and PP it is advisable to roughen the surfaces of the joint with a clean steel brush of loire-woll to remove oxidisation from the surfaces. If self-propelled equipment is

20 used it will not be necessary to remove the oxidation as greater air temperature and pressure is available on automatic machines Welding with hand-held equipment: Controlling the welding temperature. When the surface of the geomembrane starts to melt (indicated 84 a glossy finished) the right temperature has been reached. With the nozzle inserted between the two sheets apply pressure with the hand held rubber roller in quick firm strokes. The speed of welding is related to the width of the seam. A bead is formed parallel with the welding seam; the thickness of this bead should not exceed 1/3 of the thickness of the membrane. When using hand-held welding equipment the surface under the membranes must be firm and smooth in order to give the appropriate counter pressure Welding with automatic equipment: Controlling the welding temperature. Place the tow layers of membrane between the pressure rollers and set the welding speed as soon as hot air is being emitted at the correct temperature. Place the nozzle between the two sheets and at the same time on the driver motor. Care should be taken to guide the machine at even distance from the edge of the sheet to maintain an even overlap. It is not necessary to provide a firm even base when using this type of machine with a double pressure roller system. Welding temperature, speed and pressure should be adjusted and tested according to the type and thickness of geomembrane being used. The welding temperature and speed is directly dependant on each other. If the above instructions are carried out for both hand-held and automatic equipment, further treatment of the welding joint will not be necessary. Advise on site conditions during welding: In rainy conditions or strong wind as well as temperatures below +5ºC, welding should be stopped unless the area is properly covered and heated.

21 When welding goemembranes with hot-air equipment the following guidelines are to be followed: Hand-held welding: Dependent on the type and thickness of material, welding should proceed at approximately 0,2 to 0,1 m/min. Automatic welding: As above, but at a speed of approximately 0,5 to 6 m/min. It is imperative, that before site welding commences, field test are conducted under similar weather conditions and the strength of the weld tested. 8. Installation of Monarflex s geomembrane: 8.1. The excavation: The base must be well levelled and compacted to 95 % standard proctor. The excavation must appear free from stones and foreign objects that might puncture the membrane. If the virgin soil does not meet necessary requirements, it must be blinded with 5 to 10 cm. of fine gravel, or a protective geotextile Protective layer/drain layer: Thickness of layer must minimum be 30 cm. Max. grain size: 1,0 mm geomembrane = 8 mm grain size 0,75 mm geomembrane = 6 mm grain size 0,5 mm geomembrane = 5 mm grain size The laying of protective gravel can be placed with a front loader. This material must be unrolled and not dozed, as that latter may cause tension in the membrane. When placing the protective layer, it should be spread in a fan-shape as driving in the same tracks may cause deep impressions in the base. If the same entrance is used for the total area, a driving dam reinforced with geotextile must be installed. Installation of protective layers on slopes is always started from the bottom end, and must be done before anchoring the membrane in the top trench.

22 8.3. Unrolling of the geomembrane (also see drawing page 23): The pre-welded sections may be difficult to handle. That is why sections weighing more than 250 to 300 kilos are equipped with a towline, coming from the centre of the roll, so making it easier to pull out the sections. The unrolling can be done by hand, but you may facilitate the use of a front loader, for ease if availability of labour is limited. Each section would be placed on the short end of the excavation, so that the babble mark with the arrow points in the direction of unrolling. The wrapping is removed. The line is fastened to a front end loader, or similar. The front end loader reverses, so that the driver can observe the unrolling, and the same time ensure the unrolling is of constant and steady nature. The section is now lying unrolled in a flat-concertinaed form, corresponding to the full length of the excavation plus slopes and anchoring Unfolding of the geomembrane: A sufficient number of hands depending upon the size of the area line up along the free edge of the unrolled section. They pull the free edge so that the geomembrane is led over the excavation until it is fully unfolded. During this pulling out, a couple of hands are placed at the edge of the excavation assigned to keep the section in place Anchoring along the edges: When the membrane is unfolded and adjusted, the protective layer e.g. gravel is laid: at first the base and to the slopes. By following this procedure, the membrane is free to take up the undulation within the excavation. This is also the reason for folds within the excavation. Membranes laid in sunshine will contract during the night so becoming tight, thus reinforcing the use of the above method. Anchorage of membrane can be executed either by tucking the edge of the membrane into a trench, or by covering it with soil or turf Traffic on uncovered membrane:

23 No vehicles are allowed on the membrane. Personnel traffic is only allowed with rubber footwear Starting the laying of e.g. domestic waste: If the waste consists of long sharp and pointed objects, e.g. refrigerators, long iron rods, bicycles etc., it is essential to make sure that the first layer of waste consists of a thickness that prevents the compactor from pressing the sharp objects through the gravel layer, so perforating the membrane.

24 8.8. Installation in hot weather: The MONARFLEX geomembranes has a thermal expansion coefficient on 0,19 mm/m/cº. When a membrane is installed on a sunny day, the temperature might easily reach 70ºC in the membrane. Then when the membrane is cooled, e.g. when temperature drops at night or when filling water into the basin (membrane area), it will result in that the membrane will contract. Please see example below: Membrane length: 26 m Membrane temperature day: 70ºC Membrane temperature night: 15ºC Temperature difference: 55ºC Thermal expansion coefficient: 0,19 mm/m/ºc Contraction at cooling: (55 x 0,19 x 26) ~271,7 mm = 27 cm. Due to this fact it is of utmost importance, that the membrane has not been fastened too tightly, when the temperature is high or in too sunny weather. It is recommended to lay out the membrane with a few folds or waves along the surface as illustrated on the sketch below. Sketch:

25 Backline membrane 9. Installation hints: Securing to structures e.g. concrete or wood. Polyethylene has an apolare nature so gluing the membrane is therefore impossible. A few mastics and double sided adhesive strips can be used to join the membrane, but the adhesive offers no mechanical strength, and welding is therefore advisable whenever possible. When securing to structures the utmost care must be taken to ensure the joint is completely watertight. Generally speaking a watertight seal to a structure will require a gasket plus a mechanical fastening. It is most important to select suitable gasket material e.g. neoprene strip 3 mm thick (55 shore). The following mastics and adhesive strips can be used in conjunction with the Monarflex geomembranes. We would recommend the Terostat double adhesive tape when used for membranes (only for normal weather conditions). If the weather conditions are not optimal it might be necessary to use other methods of joining, depending on the climate (please ask for guidance at Monarflex). It is recommended that field tests of joining materials be carried out before the installation takes place.

26 10. Geomembrane Installation details: WELDING PRINCIPLES: Extrusion welding With control wire. Hot air welding with Control channel. Peel - test

27 GEOMEMBRANE INSTALLATION: Protection layer min. 30 cm. Soil Geomembrane Base layer min. 10 cm stone free gravel. Protection layer min. 30 cm. Geomembrane Geotextile Levelled & stone free soil. Soil. ANCHORING - TRENCH Protection layer min. 30 cm. Geomembrane Min. 10 cm stone free gravel. Soil.

28 GEOMEMBRANE PIPE FLANGES: Geomembrane Hose- clips Concrete pipe Welding Hose- clips Flange Mastic Concrete pipe Geomembrane Flange Welding Geomembrane Glass fibre pipe Concrete pipe Concrete plate cast in-situ Mastic UDM-S2 Knifing-filler Bolt-on-flange O-ring O-ring PVC - pipe

29 3 mm Neoprene gasket Geomembrane