All structures made of stone, brick masonry, or concrete can use the epoxy grouting. The deterioration of structures is accelerated by moisture intrusion caused by chemicals like nitrates and chlorides.
The process of deterioration accelerates if structures are constructed near the sea or on highly contaminated ground soils. Stone masonry constructed with interior stones like sandstones and laterite, etc. Spalling can occur due to moisture ingress. Brick masonry made with porous bricks also suffers from spelling action. Poor drainage can further cause the structure’s degeneration by allowing lime and cement to leach, causing them to fail.
It is well-known that adhesion between old, damaged concrete or masonry and new concrete or masonry is poor. This is because cement doesn’t have enough time to set and harden before it can be used over newly repaired structures. This causes frequent repairs to the same spot.
Epoxy grouting can be used to overcome this drawback.
Epoxy resins have many advantages
These are the advantages of epoxy resins over cement as a bonding material.
1. Quick setting 2. Low shrinkage
3. To fill hair cracks, it is low in viscosity Material with high adhesion
5. Stable at all temperatures
The epoxy resins are made up of the condensation products of Epichlorohydarin, Bisphenol-A and Bisphenol A. They have high adhesive strength and thermosetting properties. They are virtually indestructible and resist wear as well as most chemicals. Mix the resin and hardener together to initiate the chemical reaction that will lead to hardening. The mixture’s pot life can vary from 30 minutes to 120 minutes, depending on the temperature outside.
The type of hardener. Silica flour can be used to prepare mortars. For the best pot life, temperature, and application, it is important to follow the manufacturer’s instructions. Plastic vessels are recommended for mixing Epoxy components. Fig.
These are the requirements for epoxy to be applied to the surface.
1. Solid and sound
2. Clean and dry
3. No oil, grease, or other lose material
5. Free from dust and debris
It is important to remove all external materials from the surface. This can be done with compressed air if necessary. Low viscosity epoxy resins can be used for thin cracks. To ensure that vertica1 cracks are filled completely, grouting must be done from the bottom up.
A V-shaped groove is created along cracks before grouting. Any concrete fragments that are not completely removed with a jet of water are also removed. At intervals of 15-30 cm, nails are driven into cracks. Copper, aluminum or M.S. pipes are used. A sheath of 40 to 50mm in length and 6 to 9mm in diameter is inserted around the nails. Then, let them rest on it.
All cracks are now sealed with Epoxy putty. These tubes allow for unobstructed access for Epoxy resin to cracks, as well as an outlet for entrapped air.
The bottom-most pipe is used to inject epoxy of the desired formation. All pies are kept clear except for the one next by wooden plugs. You can use suitable nozzles to inject epoxy from an air compressor or other suitable machine.
It is common to apply a pressure of 3.5-7 kg/cm2. Epoxy should be injected as soon as it starts to leak from the nearby open pipe. The pressure can then be increased to the desired level for 2 to 3 seconds.
The same procedure is repeated for other pipes. The copper pipes’ excess resin is removed with a spatula. Finally, the surface of the pipes is cleaned using a rag that has been soaked in a non-flammable solvent. Rubber gloves are recommended for this task. After the work is completed, it is important to wash the equipment with acetone.
A 300-4000-micron thick coating with solvent-free epoxy suffices for a superficial network containing fine cracks. This will not compromise the structural stability. Epoxy putty is a mix of Epoxy, hardener, and china clay that can be partially filled in larger cracks that aren’t expected to compromise the structure’s suitability.
Epoxy is a very expensive material. It should not be used in areas below the bed blocks or cracks in RCC/PSC slabs, girders, etc. where dynamic forces could be transmitted.