Concrete Crack Repair Methods – Part I

Epoxy injection

Concrete cracks as narrow as 0.002 in. (0.05 mm) might be glued with epoxy. The approach usually entails treating the epoxy under pressure into the crack and establishing entry and ventilation ports at near intervals over the fractures. Epoxy procedure has been successfully used for structural crack repair in concrete buildings, bridges, dams, as well as other forms of tangible constructions. Nevertheless, unless the reason for the cracking is re-mediated, it’ll probably recur nearby the initial fracture. Then two options are available, if the reason for the chips can’t be removed.

One is always to rout and close the split or set up a joint that’ll allow for expansion and then inject the crack with epoxy. This technique isn’t relevant when the crack is actively leaking and can not be dried-out. Wet cracks may only be closed using moisture tolerant products, such as Tampur, as the imperfections could reduce the effectiveness of the epoxy to structurally fix the fractures.

Epoxy procedure requires a high amount of skill or accurate delivery, and the ambient temperature may limits application of the technique. A flexible adhesive is considered the same as a rigid adhesive due to the thin layer compared to the constraint imposed from the surrounding concrete.

Clean the Crack

Contaminants for example fine particles, or oil, grease, dirt or cement flakes decrease the efficiency of repairs, and stop bonding and epoxy penetration. These should be eliminated by cleaning or flushing with other special cleansing options or water. The crack should be as clean as much as possible

Seal the Crack

Surface cracks should be sealed to keep the epoxy dripping out. Where there’s backfill, or a back-slab has been fixed, the substrate or backfill material may also be an adequate seal. The surface can be sealed and harden through the use of an epoxy or suitable securing material to the surface of the break. A surface plastic sealer may be utilised over the the split and once finished, the surface layer could be stripped away to uncover the gloss-free surface. Where appearance of the finished work is very important cementitious seals can be utilised. If exceptionally high injection demands are essential, the crack can be cut out to a range of 1/2 in. (13 mm) and width of approximately 3/4 in. (20 mm) in AV-design, injected with an epoxy, and struck off flush with all the floor.

Install the venting and entry ports.

Three techniques come in general use:

Inserted into drilled openings – This technique was the first to be properly used, and it is usually used in conjunction with V-groove cuts into the cracks. This can be achieved with a v-grooving machine. The strategy involves drilling a gap into the groove, around 3/4 in. (20 mm) in dimension and 1/2 to 1 in. (13 to 25 mm) below the height of the V grooved area.

Flush fitting – A method commonly used to supply an entry point where v-grooving cannot be achieved. The fitting that is flush comes with a flanged base that’s glued to the concrete and the top is open for the adhesive to enter.

Disruption in seal – Another process would be to omit the seal from a portion of the fracture. This technique can be used when specific gasket units can be found that cover the unsealed part of the fracture and permit treatment of the adhesive into the split without dripping.

Epoxy Injection method

Combine – This is performed by batch or continuous techniques. In batch mixing, the components are premixed based on the manufacturers instructions, often to ensure a consistent colour mixing. Care should be taken to mix only the amount of adhesive which can be applied just before start of gelling begins.

Inject the epoxy – Hydraulic pumps, color stress pots, or air-caulking guns may be used. The pressure useful for epoxy injection is critical. To much pressure frequently won’t accelerate the injection rate. If it is a vertical crack, the procedure process must start by working epoxy in to the access slot at the lowest spot before epoxy stage reaches the entry slot above. Horizontal concrete crack injection should proceed from one end of the crack towards the other with the same approach. The injection is complete when the pressure might is preserved. When the pressure can not be maintained the the epoxy is still flowing into portions of the crack..

Remove – the surface seal should really be removed by grinding off after the inserted epoxy has completely cured.

Alternate technique

For significant structures, an alternative procedure consists of drilling a series of slots [often 7/8 to 4-in. (20 to 100-mm) diameter] the crack is intercepted by that in a number of locations. Generally, pockets are spread at 5-ft (1.5-m) intervals.

Summary

Prior to deciding on a method to repair cracks in concrete it is important to ascertain the reason behind the cracking. If the crack is due to drying and shrinking then the cracks will typically stabilise after a period of time. If the cracks are due to foundation settling then the cause of the issue will need to be addressed or the problem will re-arise.