Cracking is the complete or partial separation of concrete by breaking or fracturing, leading to cracks. Concrete structures may develop cracks for several reasons including temperature and plastic shrinkage variations, thermal variations, shrinkage shrinkage due to drying shrinkage shrinkage shrinkage chemical reactions weathering processes structural overloading.

Poor construction practices include insufficient water content in the concrete mix, inadequate formwork installation and ineffective curing practices.

Cracked concrete signals structural stress or lack of durability, and can weaken structural elements or allow water ingress which causes property damage. Furthermore, cracks have an adverse impact on interior and exterior aesthetics of buildings.

Crack ⁠Concrete Repair is necessary to preserve both the structural integrity and aesthetics of concrete structures, and can take various forms, depending on their size, location and severity. There are various effective techniques for fixing concrete cracks; here are seven of them: 

Epoxy Injection

Epoxy injection is suitable for narrow, non-structural cracks that don't pose structural threats, due to its high compressive, tensile, and bonding strengths. Furthermore, epoxy flows easily and can penetrate cracks as narrow as 0.05mm with ease - as well as being applied under pressure so it fills even deep-end crevices of cracks with ease.

Epoxies have limited tolerance to weather elements and work best when applied internally for cracks, though they don't fare so well on wet surfaces; wet surface cracks require special grade epoxy that's much too expensive compared to alternative approaches.

Follow these steps to repair cracks by epoxy injection:

Clean the crack with a wire brush, vacuum out any loose particles and debris and seal it to prevent epoxy compound from seeping out before it has set; attached injection nipples at intervals not exceeding 300mm along the crack.

Mix the epoxy compound according to its manufacturer's instructions, then inject it into a crack, starting from one end and injecting until you can see epoxy coming out from its next nipple in line. When sealing vertical cracks, start injecting epoxy from below.

Polyurethane Injection

Polyurethane injection works well to repair non-structural cracks in wet and dump environments. Polyurethane expands 2-40 times its original volume, filling and sealing concrete cracks completely while quickly setting characteristics make it suitable for wet locations.

Polyurethane's elastic properties make it suitable for moving cracks, expanding to fill voids in new locations. Our watertight sealing properties make polyurethane injection an excellent way to seal actively leaking cracks; crack repair using this method follows the same steps as epoxy injection.

Routing and Sealing: This approach to crack repair is suitable for wider non-structural cracks that do not present structural risks, while maintaining aesthetics while preventing water ingress. The sealant used should preserve structural aesthetics while keeping out water.

This method of crack ⁠Concrete Repair entails widening the original crack with routing, then sealing it off using suitable sealant. This approach is often chosen because it requires no special tools or expertise - use this procedure to repair cracks by routing and sealing:

Prepare a V-shaped groove along the crack using hand tools or pneumatic tools and clean it using either air- or water-blasting, then allow its surface to dry completely before covering with another material.

Apply sealant liberally into the groove, allowing it to set. Concrete crack repair sealants come in various Concrete Repair Materials like silicones, epoxies, polysulfides and asphaltic materials; cement grouts may crack while these might not.

Patching or Crack Filling: Patching or crack filling are among the easiest methods of hairline crack ⁠Concrete Repair. Use patching compounds like vinyl concrete patches or hydraulic cement to cover hairline cracks in concrete, while non-shrink concrete grout that doesn't shrink when dried yields the best results.

Patching hairline cracks involves cleaning them thoroughly and applying patching compound. Sealant applications are straightforward and prevent water penetration into cracks quickly and efficiently.

Stitching or Cross-Stitching:

This technique is perfect for re-establishing tensile strength across a crack. To do so, drill holes on either side of the crack before inserting metal staples or stitching dogs that can be secured using non-shrink grout or an epoxy resin-based bonding system.

Stitching dogs must be placed so as to distribute tension over an extended area, removing it from cracks. We suggest using stitches of different sizes and arrangements when stitching concrete cracks. Our procedure for concrete crack stitching entails:

As per the above guidelines, drill on both sides of a crack to create two parallel holes on either side. Clean out debris by vacuuming, and prepare stitching dogs for each pair of holes by anchoring their legs with appropriate grouting elements.