What is Concrete Canvas (CC)?-
Concrete Canvas (CC) is a flexible, concrete impregnated fabric that hardens when hydrated to form a thin, durable, water proof and fire resistant concrete layer.
What applications is CC currently used for?-
CC is typically used to replace conventional concrete for a wide range of erosion control and protection applications. Typical examples include ditch lining, slope protection, bund lining, remediation works, outfall protection, mining vent walls, gabion covering and pipe protection. Our biggest markets are the Civil Infrastructure sector (principally road and rail), Mining sector, Petrochemical sector and the Agricultural sector.
In what formats is CC available?-
CC can be supplied as either palletised bulk rolls, or man portable batched rolls. CC5 bulk rolls are 200sqm, CC8 are 125sqm and CC13 are 80sqm. CC5 batched rolls are 10sqm and CC8 are 5sqm. Due to it’s relative weight, CC13 is not available in batched rolls as standard.
What are the weights of the different thicknesses of CC?-
Concrete Canvas has nominal weights of 7kg/sqm, 12kg/sqm and 19kg/sqm for CC5, CC8 and CC13 respectively.
How is Concrete Canvas manufactured?-
CC is manufactured in our UK production plant using bespoke machinery designed by Concrete Canvas, to impregnate a custom cement blend into a 3 dimensional synthetic fibre matrix, with a PVC coating on one surface.
Which countries is CC currently used in?-
CC is currently used in 40 countries around the world and exports make up 85% of turnover. Outside of the UK our biggest markets are in Chile, Canada, Australia, South Africa, Colombia and the US.
Which contractors have previously installed Concrete Canvas in construction projects in the UK?-
Contractors include Costain Group, Carillion, Balfour Beatty, Morgan Sindall, Trant, Enterprisemouchel, Morrison Construction, Skanska, AMCO, Murphy Group, Dyer & Butler, Amey Colas, J Breheny Contractors Ltd and Raymond Brown Ltd among many others.
Which customers have previously specified Concrete Canvas for construction projects in the UK?-
Customers include Network Rail, Highways Agency, The Environment Agency, UK Coal, Bear Scotland and numerous county and borough councils across the UK.
What fire protection does CC provide?-
CC has achieved Euroclass classification B-s1, d0 and has passed the American MSHA (Mine Safety and Health Administration) fire testing for use in underground mining applications.
What level of chemical resistance does CC provide?-
CC has excellent resistance to chemical attack in particular sulphate attack, which means it is well suited for use in ground surfacing applications. The concrete we use is also much more resistant to chemical attack compared to ordinary Portland concrete. CC has passed acid (ph4 TBC) and alkaline (ph12.5 TBC) immersion tests to BS14414.
Can CC be used for Slope Protection and Stabilisation?-
Yes, Concrete Canvas (CC) is increasingly being used for slope protection, as an alternative to shotcrete to protect slopes from surface erosion caused by weathering, surface run-off and environmental degradation.
In certain applications Concrete Canvas can be used for structural slope stabilisation by combining it with steel mesh and soils nails (see CC “User guide” for more details). In this case the project should be designed by a geotechnical engineer using data from the CC “data sheet”.
What is the difference between Slope Protection and Stabilisation?-
Slope protection is where the body of the slope is inherently stable but the surface of the slope is prone to erosion from weathering and surface slip. Typically this might be on a sandstone rock face such as in this example on the Spanish rail case study. Or on slopes constructed from a mixture of small rocks and fine sand where rainfall causes loss of fines which then destabilises the slope causing rock-falls, such as in this example in Colombia.
Slope stabilisation is where the body of the slope is inherently unstable and is at risk of suffering from deep slip (where a large mass of the slope collapses). This may be caused by ground-water lubricating the soil or from other factors such as ground vibration. Conventional solutions include shotcrete, steel mesh and soil nails which are used to stabilise the slope by providing structural reinforcement. CC can substitute for the shotcrete component of this type of design for many projects but must be included as part of a solution designed by a qualified geotechnical engineer. A good example is a case study at a quarry in the UK.
How waterproof is CC?-
The level of waterproofing that materials provide is typically referred to in geotechnics using a measure of impermeability called the k-value. CC has been tested to BS1377 and been show to have an average k value of 10-9 m/s, which is similar to clay. A k value in this range is commonly referred to as being “Practically waterproof”. If the overall impermeability level is critical for your application then you will need to carefully consider the CC jointing method you use. Please see the CC “Jointing and Fixing” guide for more information.
Can CC be used for Trackway?-
Yes, CC can be used as hard armour capping of ground to prevent erosion and wash-out of fines. The load bearing capacity of the trackway should be based on surface modulus (CBR) of the ground which should be sufficient to support the requisite traffic loading. The CC should therefore only be used to provide surface erosion control rather than to increase the surface modulus of any given substrate. For this type of applications we would typically recommend 2 layers of CC13 with an offset overlap and the 2 layers screwed together. For more details see the Austrian military track way trial where CC is laid onto a well compacted substrate.
How should CC be stored prior to use?-
CC should be stored under cover in dry conditions, away from direct sunlight and within the manufacturers sealed packaging.
What is the shelf life of properly stored CC?-
When stored in the manufacturers packaging in the correct conditions, CC can be kept for up to 24 months without significant degradation in performance. Following the 24 month point CC will continue to function but it may take longer to reach the values specified on the CC data sheet.
What is the shelf life after opening CC?-
CC will start to lose performance once opened and should be used within a few days to prevent any significant degradation. It is best practise to try and reseal any packaging after opening to extend this period as much as possible.
Is it possible to lay CC in wet conditions?-
Yes. Once wet, CC has a working time of approx. 2 hours.
Is it possible to lay CC in very cold conditions?-
Yes. Warm water should be used for hydration and plastic sheeting should be applied over the hydrated Canvas during setting. Consult the CC Hydration guide for further instruction or contact Concrete Canvas directly. Generally, the same setting conditions that apply to conventional concrete pouring should be observed when installing CC.
Are there any special precautions to take when laying CC in very hot conditions?-
Yes. It is advised to install CC at dusk to avoid evaporation of the hydration water in warm environments. In very hot conditions, it is advised to re-wet the material at 2 hour intervals for the first 8 hours.
What is the lifespan of properly installed CC?-
CC has a design life of over 50 years in conditions similar to a UK climate. For advice on specific climates please contact Concrete Canvas.
Does CC require any post installation maintenance?-
Providing it is installed correctly, CC requires no regular post-installation maintenance.
How should CC be disposed of or demolished?-
CC can be demolished using standard construction demolition equipment and disposed of in the same manner as conventional concrete waste.
Is it possible to accelerate or retard the setting time for CC?-
Yes. In sufficient order volumes, Concrete Canvas can accelerate or retard the setting times of CC to accommodate different environmental conditions and applications.
Is it possible to over-hydrate CC?-
What happens if CC is under hydrated?-
The CC will not reach its full strength and the setting time may be delayed.
Will CC set underwater?-
Yes. It will hydrate fully from immersion.
Which thickness of CC should I specify?-
It depends on the application. Consult the application table in the CC User Guide or contact Concrete Canvas directly for technical advice.
What methods are there of joining layers of CC together?-
The 3 most common methods are: a screwed overlap joint, adhesive sealant joint and concrete grout joint. There are a number of other mechanical and non-mechanical methods such as pegging, hog-ringing, steel wiring, thermal welding, and general fixings such as stapling or nailing. Please see the Concrete Canvas Fixing Guide for more details.
What water should be used to hydrate CC?-
CC can be hydrated using saline or non saline water. The water does not need to be potable.
How much water per sqm of CC should be used for hydration?-
The minimum ratio of water:CC is 1:2 by weight. CC cannot be over hydrated so an excess of water is always recommended.
Is there a maximum inclination that CC can be installed onto?-
CC can be installed onto vertical surfaces.
At what intervals should CC be pegged down?-
This is dependent on the application and the quality and inclination of the substrate, but as a guide we recommend pegging at 2m intervals and at joints.
Should CC be laid fibre or PVC surface facing upwards?-
For the vast majority of applications, CC should be installed with the fibre surface exposed. The fibre reinforced concrete layer will protect the PVC backing from weathering and UV damage. If the CC is being laid with the PVC exposed it should be hydrated prior to laying.
Can CC be used without the PVC?-
The PVC is an important part of how CC functions, both in terms of maintaining its waterproof properties and preventing water loss during hydration. We do not supply CC without the PVC backing, however it is possible, although difficult, to remove this post set.
How can I cut CC?-
Prior to hydrating, unset CC can be cut using basic hand tools. It is recommended to use snap off disposable blades or handheld self sharpening powered disc cutters. After CC has set, it can be cut using angle grinders, jigsaws with ceramic blades or good quality tile cutters.
What Health and Safety precautions should I take when handling Concrete Canvas?-
General PPE precautions should be taken; face masks, protective clothing and gloves should be worn when handling CC. CC does not contain measurable amounts of soluble Chromium (VI) and is not classified as an irritant.
How does CC compare environmentally with conventional poured concrete ditch lining?-
Concrete Canvas typically replaces 100-150mm of poured, sprayed or precast concrete, resulting in material savings of 95%. This directly results in a reduction on the carbon footprint of construction works.
Has CC been granted EA (Environment Agency) approval for projects within the UK before?-
Yes. CC was approved for use by the Environment Agency (EA) Biodiversity team in 2010 for the Church Village Bypass Ditch Lining Project. Several projects have since been granted approval on a case-by-case basis.
How does CC washout affect the alkalinity of running water courses during installation?-
CC has a low wash out rate compared to other cements and a limited alkaline reserve. Unlike most concretes, it is not classified as an irritant and is less damaging to the environment.
Are there different colours of CC available?-
CC is supplied in its natural colour (mottled grey) as standard. There are a number of options for colouring CC including dying the surface fabric fibres or applying coloured surface treatments. For example the fibre surface of CC can easily be coloured by painting with a good quality exterior masonry paint.
Are there different widths of CC available?-
CC is supplied in standard widths of 1.0m for CC5 and 1.1m for CC8 and CC13. It is possible to produce narrower rolls but this would be subject to a minimum order quantity.
Can I order different lengths of material other than the standard bulk or batched lengths?-
Yes, bespoke lengths can be supplied subject to a batching surcharge.
Where can I buy ancillary CC installation products?-
Concrete Canvas can supply a full range of ancillary products for CC installation including ground pegs, water weights, jointing grout, render and sealant.
Does Concrete Canvas have international distributors for CC?-
Yes. See the Contact Us page for details about your nearest distributor.
Are samples of CC available?-
Yes. Concrete Canvas supplies small and large sample packs which contain hardened swatches and unset A4 samples of each of the three material thicknesses. Due to the volume of requests for sample packs, a postage fee will apply.
What is the price of CC?-
The price of Concrete Canvas is volume dependant and the price/sqm drops when ordering large volumes. Contact your local Concrete Canvas rep for a quote specific to your requirements and delivery location.