Elastomeric Concrete is a flexible 2-part polyurethane patching material mixed with aggregates and can be used as a filler in expansion joints which experience large movements.
The properties which are most important for these materials are flexibility, elasticity, and bond strength.
Flexibility and elasticity allow the material to absorb shock caused by traffic impacting on the extrusions.
Bond strength to the adjacent surface is critical in all conditions, both wet and dry.
Obtaining adequate flexibility and bond strength together in one material is difficult but has been achieved with this material.
The key characteristics
Elastomeric Concrete provides a flexible patch with excellent adhesion that will deflect as surrounding concrete expands and contracts and can resist heavy pressure before deflecting. The critical point is that Elastomeric Concrete allows itself to return to its original state after deflection.
FCS Concrete Repairs has successfully used Elastomeric Concrete for repairing and patching concrete floors. This includes patching across expansion joints without the need for expensive joint reconstruction or major concrete removal.
The following project photos illustrate the advantages of Elastomeric Concrete patching material:
A Patch Across an expansion joint
A Patch at the intersection of several expansion joints
Elements: Crack Injection, Cathodic Protection and Waterproof Membrane
Scope of Works
External crack repair methodology:
Mark out repair areas.
Square cut to a minimum of 10mm
Scabble back to sound concrete
Expose corroding reinforcement
Break out concrete to a minimum of 25mm behind bar.
Grit blast reinforcing
Replace corroded reinforcement if necessary
Rout non-moving cracks to
minimum of 10mm
Install anodes to steel reinforcement at 300mm centres
Check continuity of anodes to steel
Coat steel with primer
Pre-soak concrete substrate
Apply specified bonding agent to concrete only
Apply specified render material to prepared cracks
Re-apply any dried bonding agent
Cure render material immediately after finishing each repair.
Internal crack repair methodology
V-grind out cracks to 25mm
Brush specified waterproofing system into base of prepared crack
Trowel apply specified mortar to re-profile crack
Damp cure repair material with wet hessian for five (5) days
Rehabilitation of Internal Floor and Wall
Polymer Modified Membrane to be coated onto internal wall and floor of the Water Tank.
The VersEseal range seals invisible and hard to find leaks in water storage systems with a non-toxic chemical-resistant coating.
VersEseal may be used on already damaged water tanks or can seal new structures to extend the life of the tank or liquid storage structure, protecting metal from corrosion.
Application of VersEseal’s Waterproof Membrane System is straightforward, environmentally safe and free from hazardous fumes.
It can be applied in confined spaces without the heavy duty personal protective equipment that some products require.
LRM Products VersEseal – Rapid Build
textured waterproof sprayable & brushable coating for surface protection
VersEseal Rapid Build is a single component
product that may be applied using a roller, squeegee or aggregate spray
equipment. VersEseal Rapid Build is applied in thickness from 1.0 – 2.0mm.
LRM Products VersEseal – Rapid Build is a
fluid applied polymer modified emulsion and is recommended for use in a variety
of harsh environments, chemically exposed areas, temperature variations and
high traffic areas.
VersEseal Rapid Build when cured fully
adheres to the substrate to which it is applied, providing a flexible long
wearing surface and is formulated for application by brush, roller, trowel or
Applications include concrete repair,
expansion joints, foundation sealing, plumbing applications, retaining walls,
roof repair, sewage pump stations, water tank membranes, reservoirs, waste
water storage, civil pipe joints, UV protection.
Embedded galvanic anodes are designed to provide localized corrosion protection. When placed at the appropriate spacing along
the perimeter of concrete patches or along the interface between new/existing
concrete, the anodes mitigate the formation of new corrosion sites in the
existing concrete in adjacent areas.
The Galvashield XP range of embedded
galvanic anode units utilise an innovative zinc anode core design surrounded by
an enhanced formulated cement-based mortar to provide corrosion mitigation to
reinforced concrete structures. The anode units are alkali-activated (Type A)
with an internal pH of 14 or greater to keep the zinc active over the life of
the anode while being non-corrosive to reinforcing steel. The anode units
utilise 2G Technology™ to provide higher current output. Once installed, the zinc
anode corrodes preferentially to the adjacent reinforcing steel, thereby
providing galvanic corrosion prevention or corrosion control.
Bridge widening and other
Slab replacements, expansion
joint repairs and other interfaces between new and existing concrete
Repair of prestressed and
Chloride contaminated or
Proven technology –
Galvashield has an extensive 10 year track record in the field
Type A anode –
alkali-activated to maintain activity of zinc while being non-corrosive to
Cast zinc core – provides
high anode utilisation in addition to a secure long-term connection between the
zinc and the lead wires
Integral steel lead wires –
allows for quick and convenient anode installation. Provides dependable
steel-to-steel contact with no intermediate materials such as galvanising
(which can corrode over time) that may compromise the long-term electrical
BarFit™ design – grooved
edges on Galvashield XP2 and XP4 anode units assist with secure anode placement
Economical – provides
localised protection where it is needed the most, at the interface of the
repair and the remaining contaminated concrete
Versatile – can be used for
both conventionally reinforced and prestressed or post-tensioned concrete
Low maintenance – requires no
external power source or system monitoring
Long lasting – 10 to 20 year
service life* reduces the need for future repairs. *As with all galvanic
protection systems, service life and performance is dependent upon a number of
factors including reinforcing steel
density, concrete conductivity, chloride concentration, humidity and anode
Install anode units and repair material immediately
following preparation and cleaning of the steel reinforcement.
Galvanic anodes shall be installed along the perimeter
of the repair or interface at a spacing of (x mm) as specified on the drawings.
Anode spacing will vary with changes in the reinforcing steel density, the
level of chloride in the structure and the corrosivity of the local
Specifier: Typical spacing for
Galvashield XPT ranges from 430-610 mm.
The maximum anode spacing guidelines can be found on the Galvashield
XP data sheet. Anode spacing should
be adjusted for aggressive service conditions or for an extended anode
Provide sufficient clearance between anodes and
substrate to allow repair material to encase anode.
Secure the galvanic anodes as close as possible to the
patch edge using the anode tie wires. The tie wires shall be wrapped around the
cleaned reinforcing steel and twisted tight to allow little or no free
If less than 25 mm of concrete cover is expected,
place anode beside or beneath the bar and secure to clean reinforcing steel.
If sufficient concrete cover exists, the anode may be
placed along a single bar or at the intersection between two bars and secured
to each clean bar.
If repair materials with resistivity greater than
15,000 ohm-cm are to be used or the resistivity is unknown, create a conductive
grout bridge between the anode and the substrate. Pack Galvashield Embedding
Mortar to cover minimum area of 100mm in diameter between the anode and the
substrate concrete ensuring no voids exist.
Confirm electrical connection between anode tie wire
and reinforcing steel by measuring DC resistance (ohm,W) or potential
(mV) with a multi-meter.
Electrical connection is acceptable if the DC
resistance measured with multi-meter is less than 1 W or the DC
potential is less than 1 mV.
Confirm electrical continuity of the exposed
reinforcing steel within the repair area. If necessary, electrical continuity
shall be established with steel tie wire.
Electrical continuity between test areas is acceptable
if the DC resistance measured with multi-meter is less than 1 W or the
potential is less than 1 mV.
Sikadur-52 is a low viscosity, free flowing and fast curing injection resin and primer/coating based on a 2 component solvent free epoxy resin; ideally suited to a wide range of building and civil engineering applications where highly penetrative material is required. It is available in two grades, Normal and Long Potlife for moderate and high ambient temperatures, respectively.
Sikadur-52 may be used to inject and fill cracks between 0.2 – 5 mm wide in a wide variety of constructions applications.
Sikadur-52 does not shrink on curing and forms a rigid, high strength product which exhibits excellent adhesion to most construction materials enabling the restoration of structural adequacy to columns, beams, foundations, decks and water retaining structures.
Due to its highly penetrative nature Sikadur-52 is ideally suited for application as a primer beneath Sikadur epoxy mortars or Sikafloor mortars and coatings on dense substrates.
Sikadur-52 may also be used to stabilise weak and friable substrates.
Special high strength grades can be made to order.
Insensitive to moisture during application, cure or whilst in service
Applicable over wide temperature range
Excellent adhesion to most building materials even when damp
Prime Flex 900 XLV polyurethane resin is a low viscosity, hydrophilic resin that reacts with water and expands to form a closed cell, watertight foam. It is typically injected under pressure to seal actively leaking joints and cracks in concrete structures, including hairline cracks. This product is independently tested and proven to meet NSF/ANSI Standard 61.5 for contact with potable water.
April 9th, 2017 Posted by Tony SabaUncategorized
0 thoughts on “The Strength of the Surface of the Concrete Substrate and of the Adhesive are Critical Factors in the Use of Carbon Fibre Reinforced Polymers”
Carbon Fibres have been developed for the aerospace industry which needed a material which combined high strength, high stiffness and low weight. In recent years the Construction Industry have recognised the potential of this material to provide solutions for problems associated with the strengthening of deteriorating infrastructure.
When CFRP is used externally to strengthen concrete elements in a buildings, bridges etc the bond between the CFRP and the concrete substrate is critical.
The strength of the adhesive and the degree of stress at the interface determine whether the CFRP delaminates and failure occurs. The shear strength capacity of the substrate material is therefore a major parameter of the interface region behaviour.
In testing, the failure surface was located at the top of the substrate concrete just below the bond adhesive whereas the bond product itself provided the highest pull-off strength values. (International Journal of Adhesion and Adhesives 6 January 2005)
The concrete substrate therefore must be pull-off tested to ensure that shear-tension failure of the concrete cover is not a factor and the recommended high strength adhesive must be used.
Surface preparation by sand or water blasting to expose course and fine aggregate surfaces.
Bond pull-off tests of the concrete substrate.
Measure the levelness of the prepared surface with a straight edge.
Levelling mortar should be used if necessary.
The following high strength structural adhesive is recommended by Sika for their product, Sika®CarboDur®reinforcement:
Sikadur®30 epoxy resin is used to bond the CFRP to the concrete substrate and has a high early strength and a high tensile and flexural strength.
PROCESS: INSTALLATION OF CARBON FIBRE REINFORCED POLYMER STRENGTHENING (CFRP) TO REINFORCED CONCRETE SOFFIT
FCS Concrete Repairs successfully tendered to carryout structural strengthening to the soffit of a strata unit at Manly.
Our client’s Engineer advised FCS Concrete Repairs that the unit’s soffit required strengthening and provided a marked up drawing indicating where the specified product, Sika Carbodur S1214 strengthening strips, were required to be installed.
The process of installation was carried out by FCS Concrete Repairs experienced trained staff in accordance with the manufacturer’s specifications and the client’s engineering design.
Note: FCS Concrete Repairs staff have received instruction from Sika Australia training personnel and FCS Concrete Repairs is a Sika approved applicator.
The process was as follows:
Prior to commencement the soffit substrate quality was established using the Pull-off tests with a minimum requirement of 1.5MPa and tested to ensure that moisture content was less than 4% pbw.
The surface to be strengthened was levelled where necessary to provide maximum .
The substrata was cleaned of any contaminants and loose material.
The substrata was tested to ensure that moisture content was less than 4% pbw.
Ambient temperature was between the required 8°C and 35°C.
Substrate temperature was atleast 3°C above the dew point.
Sikadur 30 adhesive was used to fix the Sika CarboDur S1214 Carbon Fibre Reinforced Polymer strips(CFRP) to the soffit and was mixed as per the Sika product Technical Data Sheet.
Sikadur–30 is a thixotropic adhesive mortar based on a 2-component solvent free epoxy resin which has the following properties required for the application of the product to the soffit:
Tensile Properties (ASTM D-638)
Tensile strength is a measurement of the force required to pull something such as rope, wire, or a structural beam to the point where it breaks.
7 day Tensile Strength 3,600 psi (24.8 MPa)
Flexural Properties (ASTM D-790)
Flexural strength, also known as modulus of rupture, or bend strength, or transverse rupture strength is a material property, defined as the stress in a material just before it yields in a flexure test.
14 day Flexural Strength (Modulus of Rupture) 6,800 psi (46.8 MPa)
Shear Strength (ASTM D-732)
Shear strength represents how hard you can try to cut it without it breaking.
14 dayShear Strength 3,600 psi (24.8 MPa)
Sika CarboDur S1214 CFRP strips were installed in the designated locations on the soffit of the unit using the Sikadur 30 adhesive.
Sika CarboDur can be used to strengthen reinforced concrete due to loading increases, structural damage, changes in the structure or design or construction defects.
Sika CarboDur S1214 is 120mm wide, 1.4mm thick and can achieve very high tensile and flexural strengths:
Elastic Modulus >165,000 MPa
Tensile Strength >2,800 MPa
Mean Value of Tensile Strength at Break > 3,050 MPa
Sikadur 30 was first applied to the soffit to a nominal thickness of 1.5mm and then to the Sika CarboDur laminate also to a thickness of 1.5mm.
The laminate was then placed on the surface of the soffit and rolled into the epoxy resin adhesive.
Sikadur 30 reaches it’s design strength after 7 days.
RESULT: The end result was that the soffit of the unit was structurally strengthened to the specifications of the client’s Engineer cost effectively without the need for any costly structural concrete modifications.
FCS Concrete Repairs successfully tendered to repair the concrete base slab in a water tank at the Bingara Gorge.
Our client advised FCS Concrete Repairs that there was considerable fine cracking and repairs were necessary to prevent further expansion of the cracking, water leakage and possible failure of the tank base slab.
Cracking in the concrete base slab floor extended through to the external plinth of the base slab.
Some key factors considered in determining the most appropriate repair methodology included:
Width of cracking in concrete base slab.
Stability of base slab.
Degree of movement, if any, in base slab.
Need to consolidate the structure.
Need to exclude water (or air) from contact with steel reinforcement.
Structural or flexible repair required.
Chemical nature of liquid stored.
Strength and durability of concrete base slab.
Old or new concrete in the base slab.
Based on these key factors FCS Concrete Repairs recommended the use of the Fosroc epoxy injection system TO SEAL AND STRUCTURALLY REPAIR the base slab.
The materials used were Fosroc Nitomortar AP and Nitofill LV TDS.
Fosroc Nitomortar AP was used to seal the cracks at the surface while Fosroc Nitofill LV was injected into the underlying cracks after the Nitomortar had cured.
The detailed repair process carried out by experienced trained FCS Concrete Repairs staff was as follows:
Chase cracks with a V-cut blade to 10mm depth.
Clean the crack and the surrounding slab surface, remove any loose material from the crack.
Cap/Seal the crack using Fosroc Nitomortar AP.
Fosroc Nitomortar AP is a versatile two-component, epoxy paste consistency, structural adhesive/filler. It cures, with minimal shrinkage, at temperatures above 5°C to a very strong, dense solid.
The mixed material is applied to a suitably prepared surface and quickly cures to form a complete impermeable repair unaffected by many forms of chemical attack. It is supplied as a two pack colour coded material in pre-weighed quantities ready for on-site mixing and use.
The pot life at 25°C is 60 minutes, initial hardness is 5 hours at 20°C and the mortar is fully cured at 7 days at 20°C.
Apply the mortar along the crack leaving openings at between 20 cm intervals for injection ports to be fixed to the crack. This depends on the crack size along the length of the crack.
Smooth the mortar into and along the crack using a spatula ensuring that the mortar penetrates into the crack and that the points for the injection ports are open and clear.
Use the mortar as an adhesive to attach the injection ports at each injection point and ensure that the crack is completely sealed and the port is clear and centred over the crack.
Allow the mortar to cure for five (5) hours before starting the injection process.
Curing is dependent on temperature as noted above. Curing time will be increased at temperatures below 20°C.
SAFETY INSTRUCTION: Use protective glasses during the injection process.
Fosroc Nitofill LV cartridges were used for the low pressure epoxy crack injection process.
Nitofill LV is a two part epoxy base and hardener designed for injecting cracks in concrete and masonry where there is a need to consolidate a structure or exclude water and air from contact with the reinforcement.
Nitofill LV is a high strength, low viscosity resin injection system and provides excellent bond to concrete and masonry.
Nitofill LV cartridge pack accessory items are available separately and comprise a cartridge gun, static mixer, nozzle hoses, injection flanges, flange adaptors and flange removing tool.
The Nitofill LV crack injection system process involves inserting the two part Nitofill cartridge into the cartridge gun after attaching the static mixer hose and adaptor.
The adaptor is then connected to the installed port or flange.
Nitofill LV was then injected from the cartridge through the port and into the crack until resin flows from an adjacent port.
The port is the closed the prevent leakage and the process is repeated at the next and succeeding ports until the entire crack is filled.
After the injection resin has set, atleast one (1) hours, the ports/flanges are removed using the removing tool.
Nitomortar is then used to fill any remaining surface indentations.
Subsequently any excess mortar was removed using a grinder until the original substrate profile was restored.
RESULT: The end result was that the water tank floor substrate was sealed and structurallyrepaired and the tank repair was completely watertight and structurally sound.
February 16th, 2017 Posted by Ken PenfoldUncategorized
0 thoughts on “Use of Carbon Fibre Reinforced Polymer for structural strengthening is a “game changer””
The strength of most elements in a concrete structure can be significantly improved by using carbon fibre reinforced polymer (CFRP) plates, rods, fabric and wrap for increasing flexural, compression and shear/tensile load capacity of elements such as beams, columns, suspended floors, penetrations and decks.
Metal elements can also be strengthened in any load-bearing structure.
FCS Concrete Repairs uses Sika Structural Strengthening Systems for their proven performance and durability.
Carbon Fibre strengthening can successfully extend the functional service life of a building or civil engineering structure and accommodate loading changes when function changes impose increasing demands on the structure.
FCS Concrete Repairs are experts in the use of Carbon Fibre Reinforced Polymers and can provide advice and the expertise required to successfully provide solutions.
FCS Concrete Repairs recently successfully strengthened the following structures:
FCS Carbon Fibre Strengthening Projects
Project: Apartment at 30 Glen St Milsons Point
Slab strengthening and a new void cut-out was carried out in the following sequence:
Install new Corbel CB1
Install Carbon Fibre Reinforcement plates.
Existing tendon truncation was carried out in accordance with Freyssinet’s method statement.
Cut out existing slab as per Architect’s proposed dimension and position.
The Sika Carbodur was installed to the structural surface with Sikadur 30 resin in accordance with Sika Cardodur externally bonded reinforcement method statement prepared by Sika Service AG:
This strengthening process enabled the void to be cut out and even the post-tensioning tendons to be cut.
FCS Concrete Repairs skilled tradesmen contributed to a very successful outcome for the client.