GEOFABRICS AUSTRALASIA PTY LTD

FAQ


Megaflo
	I have to design a subsoil drainage system for my road pavement. How do I make a selection between Megaflo 170, 300 or 450 mm? Your selection will be dependent upon flows expected. Please refer to the Megaflo flow capacity charts in the Megaflo brochure.
	Your brochure shows standard fittings that can be used to incorporate Megaflo with round pipe. What do I do if I want for example a Megaflo T-junction? We have custom made fittings where you can incorporate for example a Megaflo T-junction or a herringbone arrangement. Please contact your local sales branch for details.
	Can I use Megaflo horizontally instead of vertically? Yes. This placement technique can be used where you may have a lack of cover. However a minimum cover of 100 mm is still recommended.
Drainmat
	Do I install the product horizontally across the back of the wall, or fix at the top and drape down This is dependant on the height of the wall. If the width of the roll matches the height of the wall, it is easier to install horizontally across the back of the wall.
	What can I use to fix the Drainmat to my vertical structure prior to backfilling? You can use a variety of fixing products including nails, liquid nails or Bitustik, a self-adhesive two-sided tape. Backfilling operations should take place as soon as possible after fixing.
Greenflo
	What strength or class is the Greenflo pipe? The Greenflo pipe is rated as a Class 400 pipe according to AS2139 - Part 1.
Flownet
	Do I install the product horizontally across the back of the wall, or fix at the top and drape down? This is dependant on the height of the wall. If the width of the roll matches the height of the wall, it is easier to install horizontally across the back of the wall.
	What can I use to fix the Flownet to my vertical structure? You can use a variety of fixing products including nails, liquid nails or Bitustik, a self-adhesive two-sided tape. Backfilling operations should take place as soon as possible after fixing.
Geosheet
	Do I install the product horizontally across the back of the wall, or fix at the top and drape down? This is dependant on the height of the wall. If the width of the roll matches the height of the wall, it is easier to install horizontally across the back of the wall.
	What can I use to fix the Geosheet to my vertical structure? You can use a variety of fixing products including nails, liquid nails or Bitustik, a self-adhesive two-sided tape. Backfilling operations should take place as soon as possible after fixing.
Megacell
	Why do I need to place a layer of sand over the geotextile? The layer of sand is placed over the geotextile to act as a primary filter. This is to ensure that coming into direct contact with the topsoil does not compromise the geotextile, acting as a secondary filter. Compatibility of the geotextile and the topsoil can only be confirmed following laboratory testing.
	Can I traffic the Megacell panels in order to mechanically place my sand layer? Yes. A bobcat or similar plant item can be used. Megacell's crush strength is rated at greater than 200 kPa or about 20 tonnes/m2.
Tensar Geogrids
	What is the difference between Tensar RE and Tensar SS geogrids? The Tensar RE geogrids are uniaxial which means they are designed to carry load in the one direction. The major strength is in the roll direction. The Tensar RE range includes 40RE, 55RE, 80RE and 120RE. The Tensar SS geogrids are biaxial which means they are designed to carry load in both directions. The Tensar range includes SS20, SS30 and SS40.
	Does the grade number have anything to do with the strength of the product? The Tensar RE range numbers indicate only the general range. The Tensar SS range numbers do indicate the ultimate strength of the product in both directions. ie. Tensar SS40 has 40kN/m ultimate tensile capacity in both directions.
	Which type of Tensar do I use for retaining walls? Tensar RE geogrids. They are designed to carry large tensile loads for extended periods of time.
	What are the advantages of using Tensar geogrids? The Tensar RE geogrids; - interlock well with fill material, • don't corrode, • are not effected by hydrolysis, • can with stand the extremes of the pH range, • can be embedded into concrete and mortar for the use in retaining walls, The Tensar SS geogrids: - interlock with roadbase materials, • are robust to withstand the road construction equipment, • have a proven track record in the field for over twenty years.
Bitac
	When do I need to apply Bitac primer to ensure the Bitac multi laminate tape adheres to the pavement? You need to place Bitac primer on extremely course or uneven surfaces, such as milled asphalt roads and concrete joints. Primer is also recommended if the ambient temperature is below 180 C.
	What is the application rate of the Bitac primer? The Bitac primer shall be brushed or rolled on at the minimum rate of 4 m2/litre. This rate may vary depending upon the hungriness of the asphalt or concrete surface.
	After what time period can I lay asphalt over the placed Bitac tapes? Immediately. Just ensure that all air bubbles have been removed, and the strips have been rolled firmly into place to ensure a positive bond.
Bituthene
	When do I need to apply Bituthene primer to ensure the Bituthene tape adheres to the pavement? You need to place Bituthene primer on extremely course or uneven surfaces, such as milled asphalt roads and concrete joints. Primer is also recommended if the ambient temperature is below 180°C.
	What is the application rate of the Bituthene primer? The Bituthene primer shall be brushed or rolled on at the minimum rate of 4 m2/litre. This rate may vary depending upon the hungriness of the asphalt or concrete surface.
	After what time period can I lay asphalt over the placed Bituthene tapes? Immediately. Just ensure that all air bubbles have been removed, and the strips have been rolled firmly into place to ensure a positive bond.
Sealmac
	What roll widths can I get it in? Sealmac is manufactured at our factory in NSW, Albury giving us the flexibility of a range of widths up to 4.2m wide. Standard roll size is 4m widths by 300m lengths.
	How long does it extend the pavement life? Sealmac has been proven to extend the life of the pavement for up to 10 years.
	What is the melting point? Sealmac is manufactured using PET (Polyester) having a melting point of 250°C well above the normal spraying temperatures of bitumen of 150 to 190°C.
	What is the difference between PF1 and PF2 and where would I use each? PF1 is manufactured at 140 g/m2 and is generally used for resealing applications on existing road surfaces and new bound sub-grades. PF2 is manufactured at 180 g/m2 and is used directly on clay or unbound sub-grades in low volume Rural roads to reinforce the chip seal.
	Why is Sealmac light grey? The light grey colour helps identify bitumen being absorbed into the Sealmac after rolling. White fabric is too dazzling in sunlight and black fabric is difficult to see bitumen absorption.
Bidim
	What grades are available? Geofabrics main range of bidim geotextiles is the A-grade geotextiles (A12, A14, A24, A34, A44 and A64), however, Geofabrics also manufacture bidim geotextile to specific Road Authority specifications.
	How do I select the grade of bidim to use? The most common selection method is the "Suggested Geotextile Selection Guide" contained in the bidim brochure (available in the On-Line Product Brochure). An alternative method is to adopt that outlined in NSW RTA QA Specification R63 "Geotextiles (Separation and Filtration)". The parameters in selecting the correct grade of bidim geotextile vary, but may include: • the application the geotextile is to perform (eg separation or filtration) • the environment into which it is placed (eg CBR values for the subgrade) • the size of aggregate being placed on the geotextile, and height from which it is dropped • the axle loads of the vehicles trafficking the geotextile, and depth of fill on the geotextile prior to being trafficable
	How do I join adjacent rolls? The most common way of joining adjacent rolls is to overlap the edges of the rolls. The minimum recommended overlap depends upon the nature of the application, however as a general rule, a minimum overlap of 500mm is recommended for most applications.
ELCOMAX
	What is ELCOMAX made of? ELCOMAX is manufactured from first quality staple fibres of either polyester or polypropylene. The full range of products however also incorporates nylon, aramids, and high-density polyethylene.
	What is staple fibre? Staple fibre is an individual fibre of pre-determined polymer and characteristic (e.g. polyester, polypropylene, nylon) which displays specific mechanical characteristics, such as fibre diameter (denier or decitex), strength and elongation, U.V. characteristics, cut length, crimp level, colour, and other specific considerations for the application at hand. These characteristics are able to be customised for the end user and vary greatly according to the requirements of a product 'recipe.
	Why is staple fibre the preferred geotextile for coastal applications? Marine and coastal applications place very high demands on a geotextile, particularly abrasion resistance caused by aggressive water borne sediment and sand, and high in-plane flow requirements for revetment applications during wave attack and rapid draw down situations. Staple fibre geotextiles display a high level of robustness, durability and hydraulically stable characteristics.
ELCOSEAL
	Why does ELCOSEAL require a minimum of 300mm cover soil? ELCOSEAL does not require welding or physical joining of panels in the field. Instead the product relies on the swelling and self-sealing properties of the bentonite and the confining stress from the soil cover layer (or equivalent) to seal adjacent, overlapped panels. Cover soil/material also prevents UV damage of the geosynthetics used in the manufacture of ELCOSEAL and also prevents erosion of the bentonite out of the composite.
	Can I install ELCOSEAL myself, or do I need an experienced contractor, liner installer? Yes, most small earthworks contractors or small construction crews can install a GCL without prior experience. In fact, approximately 50% of GCL installations are performed by crews with no previous GCL installation experience. Geofabrics will provide the necessary loading frames, we also supply the necessary bentonite paste pre-mixed, and we offer installation guidance prior to project commencement.
	How many square metres can I install in a day? It depends on the site and project type! For a large, flat landfill base liner or cap, an efficient crew (of 2 to 4 people) with an excavator and a front-end loader (or similar) for transporting rolls to the installation point have been able to install in excess of 6000sqm per day. For smaller irregular-shaped containment or storage facilities installation rates of 1500-3000 sq.m per day are typical.
Enviromat
	Can Enviromat be used in channel flow applications? Enviromat™ is not recommended for channel applications, for, during the initial unvegetated phase, the only protection afforded the seeded soil is via the erosion control blanket. Whilst the Enviromat™ will afford some protection, it is designed to protect soil from rainfall splash effects and runoff (i.e. embankments). However, Enviromat™ has been used successfully in low velocity installations. CIRIA Report 116 "Design of Reinforced Grass Waterways" describes the relationship between the differing erosion control products and flow velocity and duration in graphical form, as reproduced below. From this graph, one can estimate the maximum flow velocity Enviromat™ can resist for a given duration.
Geoweb
	What are the key parameters for design of an Geoweb structure? The key parameters for designing an Geoweb structure are detailed in the Geoweb Technical Support Manual, available from Geofabrics Australasia. However, the key criteria can be summarised thus: Embankment applications: i. slope geometry ii. soil characteristics iii. Geowebcocell geometry and possible anchoring details Channel lining applications: i. flow velocity ii. selection of infill material The Geoweb Technical Support Manual describes the design methodology for an Geoweb installation.
	How does Geoweb work in slope or channel lining applications? Geoweb is a geocell, or a soil confinement system, operating through restraining infill material in a series of honeycomb cells. Geoweb reinforces the surface layer on an embankment, and helps prevent movement of soil down the slope with the rainfall runoff. However, Geoweb provides permanent support and facilitates seeding of the soil surface. Geoweb confines the infill material in a channel lining application, increasing the velocity at which the infill material will mobilise. As the surface fines are mobilised, the cells reconsolidate, thereby further increasing the maximum velocity the system can withstand.
Grassroots
	What is the maximum flow velocity? CIRIA Report 116 "Design of Reinforced Grass Waterways" describes the relationship between the differing erosion control products and flow velocity and duration in graphical form, as reproduced below. From this graph, one can estimate the maximum flow velocity Grassroots can resist for a given duration. Thorough hydraulic testing is currently being undertaken to establish the flow velocities Grassroots can operate within.
	Can vegetation grow from beneath? The standard Grassroots product has a density of 400gsm, and whilst it is recommended that installation be via seeding from above, a number of projects have been successfully seeded from below. The result is a protective layer during the prevegetated phase with a reinforced vegetative cover following germination and growth. To develop Grassroots as the complete turf reinforcement mat, we are developing a lighter grade product with a more open structure that will protect the underlying soil and promote vegetative growth. Trials are currently being undertaken.
	Can Grassroots be customised in terms of colour and dimensions? As Grassroots is manufactured in Australia , it offers flexibility that cannot be achieved with imported products. As such, for projects of sufficient size, the manufacturing process can be adjusted to manufacture Grassroots in alternative colours and dimensions, within supply and manufacturing constraints. Customisation to project requirements may incur additional costs, depending upon the nature of the customisation.
Silt Fences
	What is a composite fabric and why does the Silt Fence 2000 product use this instead of just a woven fabric? A composite fabric is the combination of a woven and a non-woven geofabric mechanically needle punched together. Silt Fence 2000 is manufactured using this composite fabric as it produces a small pore size to prevent silt material passing through the silt fence. It also introduces rigidity to the fabric in order to maintain verticality in service.