CHAPTER-1
INTRODUCTION
Concrete cloth is an upcoming revolution in civil world, which in turn have a wide range of application in rapid construction, in state of emergency etc. due to its own physical property, mainly, flexibility and easy to use. Among various engineering applications of 3D spacer fabric reinforced cementitious composites; concrete canvas (CC, the concept was first proposed by Brewin and Crawford in 2005) is one of the most promising products.
Concrete cloth is a flexible concrete impregnated fabric that hardens on hydration to form a thin, durable, water and fire proof layer. Like soft cloth,CC can closely cover the surface of arbitrary structure or element before using. Its shape is completely the same as the outer profile of the structure or element where CC is covered. Essentially, it’s concrete on a roll.CC allows concrete construction without the need for plant or mixing equipment. Simply position the canvas and just add water. The water does not need to be potable, and bore-hole water, river water or seawater can be used. No major ground excavation or foundation work is required.
Concrete cloth consists of a 3- dimensional fiber matrix containing a specially formulated dry concrete mix. A PVC backing is provided on one surface to make it water proof. The other side of the cloth is aided with a hydrophilic fiber (polyethylene and polypropylene yarns) and thus hydration occurs by drawing water into the mixture.
The cloth may be hydrated either by spraying or by being fully immersed in water. To check whether water penetrated through the whole thickness of the sample, it was cut along the cross section after hardened. It was seen that the density of the paste in bottom layer was similar to the top layer. Therefore, the current water-spaying method guarantees that the water penetrated through the whole thickness of sample. The time-dependent compressive strength of cubic CSA-based CC sample with dimensions of 15 mm x 15 mm x 15 mm was also determined to obtain the suitable curing age for tensile test and 10-day compressive strength of the sample almost reached the maximum mechanical strength value. The geometric patterns of outer textile substrates of 3D spacer fabric play a vital role in loading capacity and the solid fabric dominate the tensile strength and ultimate elongation.
They can be easily nailed, stapled or coated with an adhesive for easy attachment to other surface. Once set, the fibers reinforce the concrete, preventing crack propagation & providing a safe plastic failure mode. Compared to traditional concrete solutions, it is faster, easier and more cost effective to install and has the additional benefit of reducing the environmental impact of concreting works by up to 95%.
Typical installation speeds are up to 10 times faster than conventional concrete solutions. It is available in man portable rolls eliminating the need for plant on site and allowing concrete installation in areas with limited access.
Prior to hydration, Concrete cloth layers can be cut to length using basic hand tools eliminating the hazards associated with using power tools in high risk environments. The concrete is pre-mixed so there is no need for mixing, measuring or compacting but just add water. It greatly reduces transportation cost and on site storage. It is a low mass, low carbon technology.
Fig 1.1 CC cross section
(Source: www.concrete canvas.co.uk)
CHAPTER-2
HISTORY OF CONCRETE CLOTH
The British Engineering Company had found the revolutionary material, concrete cloth. It’s a recent innovation in the concrete sector.The technology was first found for emergency shelters, application to military world and later on applied to commercial construction work.
2.1 CONCRETE CLOTH AS REINFORCING SANDBAGS
The British Army used the method of reinforcing sand bag for defence; this reduces the degradation of sandbags (figure given below) in extreme climates of Afghanistan, where the combination of wind, sand and extreme temperature affects the sandbags for a frequent repair. Moreover it was fireproof.
They are made compact to work even in remote areas by manufacturing them in a compact size (10 m or 33 ft), made them easy to handle without any of the heavy lifting equipment’s or planting machinery’s. That forms a biggest advantage when work in remote area where the helicopter is the only way to mode of transport.
The fibers used in them forms a reinforcing matrix within the concrete cloth. Thus when impacted this property of fibers used helps to serve the structural integrity of concrete. A ballistic attack may pass through them, but crack propagation is limited, as a result, the sandbags remain safe inside the concrete shell.
In January 2008, a notable amount of concrete cloths are laid in the frontline in Afghanistan to analyze the field usage and the performance which is satisfactory for the U.K army.
Fig.2.1.1 CC as reinforcing sandbags
(Source: www.concretecanvas.co.uk)
2.2 CONCRETE CLOTH AS DEPLOYABLE SHELTER
The research of concrete clothes is to develop rapid hardening shelters only using the water and air. Concrete Canvas Shelters have two major advantages over conventional tented shelter:
1. Operational: It enables a hardened structure from day one of an operation. They provide much better environmental protection, increased security and vastly improved medical capability.
2. Financial: They have a design life of over 10 years, whereas tents wear out rapidly and must then be replaced. They are a one stop solution, saving effort and cost over the lifetime of medium to long term operations.
The key was the use of inflation to create a surface that was optimized for compressive loading. This allowed thin-walled concrete structures to be formed that are both robust and lightweight.
The University ofBath in Bath, UK, has conducted finite element analysis of the shelters, showing that the structures can withstand a high distributed compressive load.
2.2.1 PACKAGING
Concrete Canvas Shelters (CCS) are supplied in polyethylene, airtight, water proof, rot proof sacks within ISPM15 heat treated timber/ply panel crates.
CCS are rapidly deployable structures that can be deployed by two people in less than 24 hours. There are two shelter sizes available, the CCS25 and the CCS50 with respective deployed areas of 25 and 50sqm.A CCS50 will require a vehicle or winch to aid with the unfolding of the shelter prior to inflation. Each shelter is provided with the ground pegs required for inflation. CCS are prefabricated structures consisting of Concrete Canvas fixed to an inflatable inner with integral steel door sets at each end. The shelter is deployed in the following four stages:
2.2.1 a. Delivery
The shelter is supplied folded and sealed in a sack. The 16 m2 variant is light enough to transport in a pickup truck or light aircraft.
2.2.1 b. Inflation
Once delivered, an electric fan is activated to inflate the inner PVC liner and lift the structure until it is self-supporting.
2.2.1 c. Hydration
The shelter is sprayed with water. Hydration is aided by the fiber matrix, which wicks water into the mixture
2.2.1 d. Setting
The Concrete Cloth cures inthe shape of the inflated inner PVC liner. The structure is ready to use 24 hours later.
Access holes allow the installation of services such as water, power, air conditioning, and heating units. The shelters have excellent thermal properties and protection against blasts, and small arms fire. A shelter using CC is shown in figure.
Fig. 2.2.1 CC as deployable shelter
(Source: www.concretecanvas.co.uk)
CHAPTER-3
MATERIAL PROPERTY
3.1 STRENGTH
Very high early strength is a fundamental characteristic of concrete cloth. The first crack strength of CC is attributed to two aspects: matrix strength and fiber bridging effect. The first crack strength σfc is defined as the applied tensile stress at which a matrix crack spreads throughout the cross section of the sample under tension. The maximum bridging stress σB is defined as the maximum stress that bridging fibers can transfer across the crack of specimen.
Typical strengths and physical characteristics are as follows:
Compressive testing
The test is based on ASTM C473-07.By the test the 7 day minimum compressive strength is equal to 38 MPa
Bending test:
This tests based on ASTM C-1185. The test is used to determine the ability of material to resist the bending. The 7 day minimum bending stress is equal to 3.3 MPa and 7 day modulus minimum is equal to 180 MPa.
Abrasion Resistance:
ASTM C1353-8 is the standard test method to determine abrasion resistance of the material. CC lost 60% less weight than marble over 1000 cycles.
Resistance to imposed loads on vehicle traffic areas:
EN 1991-1-1:2002 is the standard testing method (for CC8&CC13 only). The gross weight of two axle vehicle should be between 30 to 160 kN and the uniformly distributed load should not exceed 5kN/sq.m
CBR puncture resistance:
Test is based on EN ISO 12236:2007. The test is used for CC8& CC13. The minimum push-through force is equal to 2.69 kN and the maximum deflection at peak is 38 mm.
3.2 PHYSICAL PROPERTIES
Setting time
The time between the end of mixing and initial set of a material made with a hydraulic binder or the hydraulic binder itself. The initial setting time should be greater than or equal to 120 minutes and the final setting time is greater than or equal to 240 minutes. Concrete canvas will achieve 70-80% strength in 24 hours after hydration.
Density
The dry density of Concrete Cloth before hydration is 1500 kg/cc Upon Complete hydration the density increases 30-35% to a range of about 1950-2025 kg/cc.
Thickness
Concrete Canvas is available in 3-thicknesses; CC5, CC8 & CC13, which are 5, 8 & 13 mm thick respectively. There is theoretically no limit to the thickness of the fabric, although it will generally be limited by the manufacturing techniques used to produce it. A typical thickness would be between 2 and 15mm. One important consideration limiting the thickness of the material is the ability of the liquid to penetrate through the interior of the settable material before the outer portions of the settable material is set. A further limitation on the thickness comes from the increased Weight of the fabric with increased thickness and if it is too thick, the faces may not be able to support the Weight of the settable material within the fabric.
CHAPTER-4
METHOD OF HYDRATION& WORKING
Concrete cloth can be hydrated using saline or non-saline water. The minimum ratio of water to Concrete Cloth is 1:2 by weight. It cannot be over hydrated so an excess is recommended. The recommended methods are: In a hot/arid environment, re-wet the material 2 - 4 hours after the initial hydration.
Immersion:
Immerse Concrete cloth in water for a minimum of 90 seconds.
Spraying:
Spray the dry Concrete cloth with water until it is saturated. Do not use a direct jet of pressurized water as this may wash a channel in the material and create a weakened area.
WORKING
It is bifurcated into four steps
4.1. Unpacking
At the time of installation, CC comes in two forms, Bulk roles or Batched roles (shown in figure)which are flexible in nature.CC is available in two standard roll sizes; bulk rolls or smaller batched, portable rolls the quantity per roll differs between the CC types. Bulk rolls weigh about 1.7 Tons (~3400 lbs.) and are supplied on 6 inch cardboard tubes which can be hung from a spreader beam and unrolled using suitable equipment (see picture below). Bulk rolls provide the fastest method of laying CC and have the additional advantage of reducing the number of joints required.
Batched rolls are supplied on 3 inch inner diameter cardboard cores with carry handles, and can be easily handled by 2 to 4 people. All CC thicknesses can be supplied batched to custom lengths for an additional charge. Bulk rolls are individually wrapped and palletized. All CC rolls are provided with a basic hydration guide placed within the packaging.CC batched rolls are individually wrapped in airtight packaging and palletized. 10 batched rolls fit on a standard 4 x 4 pallet. CC13 is not supplied in a standard batch roll size.
FIG.4.1.1 Batch rolls
(Source: www.concrete canvas.co.uk)
FIG.4.1.2 Bulk rolls
(Source: www.concrete canvas.co.uk)
4.2. Storages
CC should be stored in dry conditions away from direct sunlight and in the manufacturers sealed packaging. If stored correctly CC has a shelf life of 24 months. If stored for longer CC may remain usable in many instances.
4.3. Cutting and Fastening
The cloth is laid on the point of application, cut into proper size and shape, and fastened to the place using staples, Nails and screws.CC A snap off type disposable blade is the most suitable tool for cutting CC before it is hydrated or set. When cutting dry CC, a 3/4 allowance should be left from the cut edge due to lost fill. This can be reduced by wetting the CC prior to cutting. Set CC can be cut as with conventional concrete, with angle grinders, construction disc cutters or tile cutters. CC can also be cut using handheld self-sharpening powered disc cutters. CC sheets in all three thicknesses can also be water cut to a fine resolution. There are a large number of mechanical fasteners that are suitable for use with Concrete Cloth. Some of these fasteners can be used in conjunction with the non-mechanical joining methods described later in this guide to improve the mechanical strength or water proofing properties of joints.
The versatility of CC means that a wide range of manual, electric or gas powered staplers are suitable for attaching CC to soft substrates such as wooden boarding for building cladding. Commercially available hand staplers are suitable for fixing 2 layers of CC together where a small amount of compression force is required - such as with the simple overlap joint described in the CCNon- Mechanical Fastening Techniques section of this brochure. Standard nails can be used to attach CC. Alternatively, a power tool such as the Hilti nail gun, provides a quick and effective method of securing CC to hard surfaces such as concrete or rock. This may be appropriate where CC is being used to recondition an existing concrete surface or for spall lining in mining applications. It is important to ensure that the nail is used with at least a 1/2 washer to ensure the head does not penetrate through the surface of the Cloth. CC fastening using standard nails and electric stapler can be seen in figure given below.
FIG. 4.3.1 CC Fastening using standard nails
(Source: www.concrete canvas.co.uk)
FIG. 4.3.2 CC Fastening using electric stapler
(Source: www.concrete canvas.co.uk)
4.4. Hydrating
After fastening of CC to desired place, it only needs to be hydrated for its final hardening. It is designed in such a way that, it cannot be over hydrated. Only in 24 hours Concrete cloth is ready to serve its purpose.
CHAPTER-5
MARKET AVAILABILITY
Concrete cloth is available in two standard roll sizes; bulk rolls or smaller batched rolls. Bulk rolls provide the fastest method of laying Concrete cloth and have the additional advantage of reducing the number of joints required.
The shelter is supplied folded and sealed in a sack. The 16 m2 variant is light enough to transport in a pickup truck or light aircraft.
There are 3 Concrete cloth types available with the following indicative specifications
5.1. ROAD
Concrete Canvas (CC) provides a durable water management and erosion control solution for new and existing road infrastructure projects. Some specific examples of applications are:
Ditch Lining
Slope Protection
Outfall Protection
CC has quickly gained market acceptance in the civil engineering sector as a cost effective alternative to conventional concrete in ditch lining and slope protection applications.
The speed of installation minimizes traffic disruption and reduces the risks associated with roadside work. CC ditches prevent weed growth and erosion, reducing the maintenance costs associated with unlined ditches, but will naturally ‘green’ over time, helping it blend into the environment.
Existing users of CC in the Rail sector include:
UK Highways Agency
Enterprise Mouchel, UK
Skanska Balfour, UK
Costain, UK
5.2. RAIL
Concrete Canvas (CC) has been used in the rail sector since 2009 and is rapidly establishing itself as the construction material of choice with network providers around the world. Some specific examples of applications are:
Ditch Lining
Slope Protection
The speed and ease of installation means that CC is well suited to time-critical track-side work, vastly reducing line possessions and overall project costs. Eliminating issues associated with rebound from shotcrete means slope protection work can continue without line closures.
The resulting reduction in staffing levels and plant requirement has obvious safety benefits for contractors.
Existing users of CC in the Rail sector include:
UK Network Rail
Canada National Rail
ADIF, Spain
5.3. UTILITIES
Concrete Canvas (CC) is increasingly being used by utilities such as power, waterworks, landfill and hydro-electric companies. Some specific examples of applications are:
Ditch Lining
Slope Protection
Pipe Protection
Cable Covering
CC is increasingly being used as slope protection on sites with sensitive infrastructure such as power stations.
Unlike shotcrete, CC produces no back spray, debris or rebound, eliminating the need for site closures or costly clean-up operations post-installation. Concrete Canvas (CC) can also be used as practical, simple to install coating for pipeline or cable protection.
Existing users of CC in the Utility sector include:
Iberdrola, Qatar
Duncan Mackay & Sons, UK
COMSA EMTE, Spain
Stornaway Council, UK
5.4. MUNICIPAL
Concrete Canvas (CC) has been used on a large range of projects for national governments, public works, councils and local authorities. Some specific examples of applications are:
Gabion Reinforcement
Ditch Lining
Slope Protection
CC has an expected design life of over 50 years and has more than 200 cycles of freeze-thaw testing.
The concrete used within CC is extremely hard wearing and has twice the wear resistance of OPC; as well as excellent resistance to chemical attack and UV degradation.
Existing users of CC in the Municipal sector include:
Caerphilly Council, UK
Ras Al Kaimiah, UAE
Far North Council, New Zealand
Rother Council, UK
5.5. MINING
Concrete Canvas (CC) is being used extensively on large-scale mining projects around the world with customers in South Africa, Canada, Chile, Australia and the UK. Some specific examples of applications are:
Ditch Lining
Vent Walls
Slope Protection
CC cannot be over-hydrated and there is no need for mixing, measuring or compacting on site.CC is well suited to use in extreme environments and has been used installed in environments with sub-zero temperatures such as Northern BC in Canada and at 4000m altitude in the Chilean Andes.
Existing users of CC in the Mining sector include:
Vale, Canada
Barrick, Chile
British Gypsum, UK
Coal Authority, UK
5.6. AGRO
Concrete Canvas (CC) is well suited to agricultural applications where water management and erosion control are key. Some specific examples of applications are:
Remediation
Ditch Lining
Slope Protection
CC also has a low alkaline reserve, a low washout rate and a low carbon footprint, ensuring minimal impact on the environment.
CC can be used to reline existing concrete infrastructure in fisheries, canals or irrigation ditches, allowing time-critical remediation work to be completed quickly and easily.
Mendez Soluciones, Chile
ConcesiónSabana De Occidente, Colombia
OranjeRiet Water Users Association, South Africa
OSEPA Confed. Hidrografica del Ebro, Spain
5.7. PETROCHEMICAL
Concrete Canvas (CC) is increasingly being used by oil and gas companies around the world for a wide range of containment, erosion control and water management applications. Some specific examples of applications are:
Bund Lining
Pipe Protection
Ditch Lining
CC is typically 10 times faster to install than conventional concrete solutions, reducing plant and personnel on site and consequently improving site safety.
CC can also be supplied in batched rolls allowing work to be done in areas with limited access.
Existing users of CC in the Petrochem sector include:
Phillips 66, UK
Petrobras, Brazil
Pacific Rubiales, Colombia
Shell, UK
5.8. DESIGN
Concrete Canvas (CC) has been used by a huge variety of designers, architects and artists. From furniture to conceptual fitness apparatus, sculptures to art installations, CC’s flexibility, durability, ease of use and fabric-like aesthetic has led to it being used in projects worldwide. Some specific examples of applications are:
Furniture
Artistic
Exhibition
Pre-hydrated CC can be cut using hand tools, and the material can be fixed to itself or other surfaces in many different ways.
Set CC can be cut and drilled as with conventional concrete, using angle grinders, construction disc cutters or high-quality tile cutters. It can also be water cut to a fine resolution. CC has excellent drape characteristics, allowing the material to conform to complex shapes, and the fiber surface of CC can be easily painted once set using standard exterior masonry paint.
Existing users of CC in the Design sector include:
Wolfson Design
David Booth
Florian Schmid
Swedish Ninja
CHAPTER-6
APPLICATIONS OF CONCRETE CLOTH
6.1. DITCH LINING
Fig 6.1 Ditch lining
(Source: www.concrete canvas.co.uk)
Concrete cloth can be rapidly unrolled to form ditch or tank lining. It is significantly quicker and less expensive to install than conventional concrete ditch lining and requires no specialist plant equipment. Traditionally, the most common renovations were toreplace smaller canals with pipelines and line larger canals with concrete. But lining canals with concrete is expensive and requires significant upkeep.
Concrete Cloth is typically 10 times faster to install than conventional concrete solutions, with installation speeds of up to 200sqm/hr.
Less time required on site, less vehicle movements, manual handling issues associated with slab lining are eliminated.CC5 and CC8 are available in 60kg and 70kg man-portable batched rolls.
Concrete Canvas (CC) can be used to rapidly reline existing concrete structures suffering from environmental degradation and cracking.
CC provides a remediation solution which is fast, easy and cost effective to install.
Cost Saving: Repairing existing concrete infrastructure can prove costly, difficult and time-consuming, typically requiring the removal and replacement of existing concrete which is extremely difficult, requires heavy plant and a large site team.
Improved Impermeability: CC joints can be thermally welded or sealed with mortar to effectively reduce water loss.
Minimum Volume Loss: CC typically replaces 100-150mm of poured or sprayed concrete. Therefore re-lining a channel or reservoir with just 5, 8 or 13mm of CC minimizes capacity losses associated with conventional solutions.
6.2. SLOPE PROTECTION
FIG.6.2 Slope protection
(Source: www.concrete canvas.co.uk)
Landslides may occur due to shallow erosion orreduction of shear strength caused by seasonal rainfall, and may be triggered by anthropic activities such as adding excessive weight above the slope, digging at mid-slope or at the foot of the slope.
Concrete cloth can be used for slope stabilization and other erosion control applications such as temporary and permanent slope protection, retaining walls, boulder fences, low level bunds and river bank and dam revetments.
6.3. PIPELINE PROTECTION
Concrete cloth can be used as a coating for overland or underwater pipeline protection, providing a superior tough rock shield. In remote areas it can be used to coat steel pipe on site without expensive wet concrete application plants. It will set underwater and provide negative-buoyancy.
Fig. 6.3 Pipeline protection
(Source: www.concrete canvas.co.uk)
6.4. OUTFALL PROTECTION
Concrete Canvas (CC) has been used worldwide as an effective method of preventing surface erosion and scour associated with water run-off from culverts outlets, spillways and over-toppings.
CC provides an outfall protection solution which is fast, easy and cost effective to install.CC can be installed by personnel with minimal training. The material can be cut and fixed with basic hand-tools. CC cannot be over-hydrated and there is no need for mixing, measuring or compacting on site.
CC has double the wear resistance of standard OPC and has passed over 200 cycles of freeze-thaw testing giving it a minimum design life of 50 years in a UK climate.
Fig 6.4 Outfall protection
(Source: www.concrete canvas.co.uk)
6.5. GROUND RESURFACING
Concrete cloth can be secured with ground anchors to rapidly create a concrete surface for flooring, pedestrian walkways or dust suppression.
Repairing existing concrete infrastructure can prove costly, difficult and time-consuming, typically requiring the removal and replacement of existing concrete which is extremely difficult, requires heavy plant and a large site team.
Fig. 6.5 Resurfacing
(Source: www.concrete canvas.co.uk)
6.6. MINING APPLICATIONS
Concrete cloth can be used as an alternative to poured or sprayed concrete or as a quick way of erecting strong permanent or temporary blast and vent structures and spall lining.
Trials have shown that CC typically provides cost savings of over 20% compared to conventional solutions.
Fig.6.6 Mining
(Source: www.concrete canvas.co.uk)
6.7. BUND LINING
Earth containment bunds can be quickly lined with concrete cloth to provide an efficient, chemically resistant alternative to concrete walling. Bund lining also called a bund wall, is a constructed retaining wall designed to prevent inundation or breaches from a known source. It is a secondary containment system commonly used to protect environments from spills where chemicals are stored. CC can be used for hard armour capping of earth bunds around petrochemical tank farms, munitions depots and flood defences. CC acts as an effective weed inhibitor, eliminating the maintenance required with grassed or earth bunds whilst providing a safe surface for trafficking.
6.8. GABION REINFORCEMENT/CAPPING
Fig.6.7 Capping
(Source: www.concrete canvas.co.uk)
Gabion is a cage, cylinder, or box filled with rocks, concrete, or sometimes sand and soil for use in civil engineering, road building, and military applications.In a military context, earth- or sand-filled gabions are used to protect artillery crews from enemy fire.
Concrete cloth can be used to cap or repair gabion walls to provide long-term protection and prevent FOD (Foreign Object Damage). CC helps prevent loss of fill if the geo-textile has degraded from UV exposure or weathering and securely ties together multi-level gabion walls preventing movement and extending their life by decades.
CC provides a gabion covering solution which is fast, easy and cost effective to install. Capping: CC prevents water ingress which can cause slump due to water saturation and the migration of fines.
6.9. DUST SUPPRESSION SYSTEM IN HELIPAD
Fig.6.8 Helipad
(Source: www.concrete canvas.co.uk)
The turbulent air currents created by the helicopter rotor wash drives loose soil particles into the air.
The airborne dust particles negatively impact humans and wildlife, including aquatic life and vegetation. The dust also increases vehicle, helicopter, and equipment wear and damage due to mechanical abrasion.
So the concrete cloth was used as a dust suppression surface around Helicopter Landing Sites.
CHAPTER-7
CASE STUDY
SHERSTON RAIL DITCH
In June 2014, Concrete Canvas was used to line a drainage ditch located at the top of a railway embankment in Sherston, Wiltshire, UK. The works took place as part of the Great Western Electrification Programme (GWEP), which involves raising and replacing various bridges, upgrading tunnels and carrying out safety improvement work to parapets between London and Cardiff. In this instance, local rail bridges were being elevated which resulted in the need to remove a nearby aqueduct that couldn’t be re-positioned. The drainage channel was designed to replace this loss of water management capacity and to prevent slip of the embankment through surface erosion and saturation.
Site access was limited due to the close proximity of the rail line and plant was only accessible via rented farm space, so speed of install was paramount. Concrete Canvas® GCCM was specified due to its ease of and speed of install, which significantly reduced time on site and cost of access. With a fall of only 2mm, an unlined V ditch was deemed unsafe as ground and surface water would not drain correctly and cause risk of slip. Either an unlined ditch or a pipe work option would require regular and expensive maintenance, placing CC8 as the most cost-effective solution. Installation was carried out by BAM Nuttall with consultancy provided by Network rail in conjunction with ADAS (the Agricultural Development Advisory Service).
Loose rock was removed from the invert so that there was intimate contact between the CC8 and the base of the ditch. Bulk rolls of CC8 were called off in staggered deliveries to site providing logistical flexibility in line with the rate of install. The bulk rolls were deployed from spreader beam equipment to maximize speed of install. The material was unrolled into the ditch transversely and cut to specific profile length.
Fig.7.1 Sherston rail ditch before lining
(Source: www.concrete canvas.co.uk)
Fig.7.2 Sherston rail ditch after lining
(Source: www.concrete canvas.co.uk)
CHAPTER-8
ADVANTAGES OF CONCRETE CLOTH
RAPID CONSTRUCTION
A 25sqm CCS can be deployed by 2 people in less than 1 hour and is ready to use in only 24 hours. The material can be hydrated by either spraying it or fully immersing it in water. Once hydrated, it remains workable for 2 hours and hardens to 80% of its final strength within 24 hours.
EASY TO USE
Dry concrete cloth can be cut or tailored using simple hand tools such as utility knives. The PVC side can be supplied with an adhesive backing and the fibrous side bonds well to concrete or brick surfaces when set. It can be easily repaired or upgraded using existing cement products.
FLEXIBLE
Concrete cloth can be easily nailed through before setting. It has good drape characteristics, allowing it to take the shape of complex surfaces including those with double curvature.
STRONG
The fiber reinforcement acts to prevent cracking, absorbs energy from impacts, and provides a stable failure mode.
FIREPROOF
Concrete cloth is a ceramic-based material and will not burn.
WATERPROOF
The PVC backing on one surface ensures that concrete cloth is completely waterproof.
ADAPTABLE
Concrete cloth is currently supplied on 1.2 m wide rolls but can be manufactured with a roll width of up to 5 m. The cloth can be produced in a range of thicknesses from 5 to 20 mm.
DURABLE
Concrete cloth is chemically resistant and will not degrade in ultraviolet light. They are far more durable than conventional soft skinned tents with a design life of over 10 years.
ENVIRONMENT FRIENDLY
The material can be reused and recycled.
EARTH BERMING
The compressive structure of CCS has been modeled to be covered with sand or earth fill, to provide additional thermal mass and insulation providing excellent level of thermal performance.
CHAPTER-9
LIMITATIONS OF CONCRETE CLOTH
Concrete cloth cannot be over hydrated and an excess of water is always recommended.
Jets of high pressure water should not be impacted directly onto the concrete cloth as this may wash a channel in the material.
Concrete cloth has a working time of 1-2 hours after hydration. So CC cannot be moved once it has begun to set.
Working time will be reduced in hot climates.
If concrete cloth is not fully saturated, the set may be delayed and strength may get reduced.
CHAPTER-10
CONCLUSION
Concrete Cloth (CC) is a unique proprietary material. It is a time & material saving technique. It is very easy to place & handle. Concrete cloth is a thin, flexible, durable, water & fire proof concrete layer. CC allows concrete construction without the need for plant or mixing equipment. Concrete canvas reinforced by 3D spacer fabric with one solid outer textile substrate exhibited improved tensile behaviours.CC has a design life of 10 years and is significantly quicker and less expensive to install compared to conventional concrete. It is specially used, where the workmanship is very difficult and is mainly used in emergency works such as in military.
REFERENCES
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http://www.ijfeat.org/
3. Maqbool Akhtar, Rajendra Singh Dangi. International Journal for Scientific Research and Development Volume 3: Issue 01: 2015, pp 314-315.
www.ijsrd.com
4. F. Han et al. 3D spacer fabrics. Construction and Building Materials 65 (2014) 620–629
5. http://www.concretecanvas.com/
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