Concrete Cracks: Causes and Repair Methods
A visible crack is a symptom, not a complete diagnosis. Shrinkage, temperature change, movement, loading, settlement and reinforcement corrosion can produce different crack patterns. Before filling a crack, record its width and location, whether it is growing, whether water is passing through it and whether structural capacity may be affected. Seek an engineer's assessment for structural or progressive cracking.
A dry, stable structural crack may be a candidate for epoxy injection when a design professional specifies that method. Green Build Egypt lists UltraPoxy LV as a low-viscosity epoxy for concrete crack repair and injection. The product and method must be matched to the crack size and condition; injecting epoxy does not remove the cause of movement, and it is not a universal solution for a wet or active crack.
If the crack leaks, first establish the water path and pressure. GB AddiPlug is listed for plugging leakage in concrete, while GProof ELA is listed as a waterproofing system able to bridge certain surface cracks within its stated limit. Stopping a leak or covering a surface crack does not by itself restore structural strength. Joints and moving cracks need details that accommodate their movement rather than a rigid fill selected by habit.
Where cracking accompanies spalling, hollow concrete or corroded steel, the repair may require removing unsound material and rebuilding the section with a suitable repair mortar such as GB Rep or HiRep. The extent of removal, reinforcement treatment, bond preparation and curing belong in the repair specification. A cosmetic coating should not conceal an unresolved deterioration mechanism.
The selection sequence is to diagnose the cause, decide whether the crack is active or dormant, define the repair objective, then choose and verify a method. Inspect the completed repair and monitor any movement that was identified. Product datasheets describe materials; they do not replace an assessment of the particular structure.