RELATED MATERIALS:
- MEGAPLATE carbon plates
- EPOMAX-PL epoxy adhesive paste
- MEGAWRAP-200 carbon fabric for structural reinforcement
- EPOMAX-LD two-component epoxy impregnation adhesive for composite fabrics
- EPOMAX-EK two-component epoxy putty
- MEGACRET-40 strong repair mortar, fibre-reinforced
I. NATURE OF THE PROBLEM – REQUIREMENTS:
The need to increase the flexural strength of a concrete beam or slab arises in cases such as increased loads or change of use, adaptation of existing structures to new codes, ageing of construction materials, corrosion of the reinforcement and defects in the structural member, or repairs after an earthquake. The strengthening system must improve the element’s flexural resistance and stiffness while limiting cracking and fatigue.
II. SOLUTION:
External bonding of composite materials provides an effective method for increasing flexural strength. Carbon fibre plates (MEGAPLATE) or strips of MEGAWRAP-200 fabric are glued along the tension zone of the member using EPOMAX-PL adhesive paste or EPOMAX-LD resin. The carbon plates have very high tensile strength, low weight and thickness, excellent resistance to fatigue, corrosion and moisture, and are easy to cut and handle. Bonded plates or fabrics increase the load-carrying capacity and stiffness of the member and reduce crack widths.
III. APPLICATION:
- Substrate preparation: Remove loose concrete, existing render and paint. Clean the surface thoroughly. Fill holes and level irregularities with MEGACRET-40 mortar or EPOMAX-EK epoxy putty. The surface must be clean, dry and sound.
- Application of carbon plates: Prepare EPOMAX-PL adhesive as instructed and apply it evenly on the plate and substrate. Press the plate firmly onto the substrate using a roller to ensure full contact and remove air voids. If more than one plate is needed, leave a small gap between plates to avoid splicing. Check for proper adhesion by tapping the plate; voids sound hollow and should be repaired.
- Application of MEGAWRAP-200 fabric: Coat the prepared surface with EPOMAX-LD resin. Cut the fabric strips to the required length, place them onto the fresh resin and press with a hard roller until impregnated and free of air bubbles. If multiple layers are specified, repeat the process; the previous layer should still be tacky. Impregnate the final layer with EPOMAX-LD and scatter quartz sand onto the wet surface to provide a mechanical key for subsequent coatings if needed.
IV. REMARKS:
- The structural member should be unloaded during bonding and curing of the plates or fabrics.
- Good adhesion of the composite material and proper anchorage at the ends are essential for effective strengthening. Pull-off tests can confirm substrate strength.
- Do not splice carbon plates. Leave gaps between plates and maintain spacing between fabric strips.
- The pot-life of epoxy adhesives decreases as temperature rises; prepare small batches and apply promptly. Application should be carried out when the substrate temperature is above +5 °C.
- Protect bonded plates and fabrics from direct sunlight and high temperatures during curing. Wear protective gloves and goggles and read the safety instructions before use.
- MEGAPLATE carbon plates
- EPOMAX-PL epoxy adhesive paste
- MEGAWRAP-200 carbon fabric for structural reinforcement
- EPOMAX-LD two-component epoxy impregnation adhesive for composite fabrics
- EPOMAX-EK two-component epoxy putty
- MEGACRET-40 strong repair mortar, fibre-reinforced
I. NATURE OF THE PROBLEM – REQUIREMENTS:
The need to increase the flexural strength of a concrete beam or slab arises in cases such as increased loads or change of use, adaptation of existing structures to new codes, ageing of construction materials, corrosion of the reinforcement and defects in the structural member, or repairs after an earthquake. The strengthening system must improve the element’s flexural resistance and stiffness while limiting cracking and fatigue.
II. SOLUTION:
External bonding of composite materials provides an effective method for increasing flexural strength. Carbon fibre plates (MEGAPLATE) or strips of MEGAWRAP-200 fabric are glued along the tension zone of the member using EPOMAX-PL adhesive paste or EPOMAX-LD resin. The carbon plates have very high tensile strength, low weight and thickness, excellent resistance to fatigue, corrosion and moisture, and are easy to cut and handle. Bonded plates or fabrics increase the load-carrying capacity and stiffness of the member and reduce crack widths.
III. APPLICATION:
- Substrate preparation: Remove loose concrete, existing render and paint. Clean the surface thoroughly. Fill holes and level irregularities with MEGACRET-40 mortar or EPOMAX-EK epoxy putty. The surface must be clean, dry and sound.
- Application of carbon plates: Prepare EPOMAX-PL adhesive as instructed and apply it evenly on the plate and substrate. Press the plate firmly onto the substrate using a roller to ensure full contact and remove air voids. If more than one plate is needed, leave a small gap between plates to avoid splicing. Check for proper adhesion by tapping the plate; voids sound hollow and should be repaired.
- Application of MEGAWRAP-200 fabric: Coat the prepared surface with EPOMAX-LD resin. Cut the fabric strips to the required length, place them onto the fresh resin and press with a hard roller until impregnated and free of air bubbles. If multiple layers are specified, repeat the process; the previous layer should still be tacky. Impregnate the final layer with EPOMAX-LD and scatter quartz sand onto the wet surface to provide a mechanical key for subsequent coatings if needed.
IV. REMARKS:
- The structural member should be unloaded during bonding and curing of the plates or fabrics.
- Good adhesion of the composite material and proper anchorage at the ends are essential for effective strengthening. Pull-off tests can confirm substrate strength.
- Do not splice carbon plates. Leave gaps between plates and maintain spacing between fabric strips.
- The pot-life of epoxy adhesives decreases as temperature rises; prepare small batches and apply promptly. Application should be carried out when the substrate temperature is above +5 °C.
- Protect bonded plates and fabrics from direct sunlight and high temperatures during curing. Wear protective gloves and goggles and read the safety instructions before use.
