What to Do About GRC Cracks? Graded Crack Treatment and Qinglong's Patented Repair Technology

Cracks in GRC need to be graded and classified for treatment based on crack width, depth, and distribution characteristics. A proper treatment plan can effectively restore structural performance and prevent deterioration from progressing. Qinglong Group classifies cracks into three grades: hairline cracks (width ≤0.2mm), minor cracks (0.2-1mm), and structural cracks (>1mm), and has developed corresponding repair techniques for each grade. Through 28 years of technical accumulation, our comprehensive crack treatment solution has been validated in hundreds of projects, with post-repair component performance recovery rates exceeding 95%.

Hairline cracks are typically surface shrinkage cracks and do not affect structural safety. Qinglong Group treats them with penetrating sealers, using capillary action to draw low-viscosity epoxy resin into the cracks, which cures to form an integral protective layer. In Hainan's high-temperature, high-humidity environment, this treatment effectively prevents moisture ingress that could cause cracks to widen. Minor cracks require a pressure grouting process, in which modified epoxy resin is injected into the cracks using a specialized injector, with grouting pressure controlled at 0.2-0.5MPa to ensure dense filling.

Structural cracks are often accompanied by reduced load-bearing capacity and require reinforcement measures. Qinglong Group's triple protection process of "surface sealing + internal grouting + external reinforcement" works as follows: first, a V-shaped groove is cut along the crack and the surface is sealed with elastic sealant; then high-fluidity epoxy resin is injected under high pressure; finally, carbon fiber fabric is bonded to the surface or an additional steel wire mesh render is applied for reinforcement. This systematic repair method was successfully applied during the maintenance of the Wuhan Han Show Theatre, restoring the structural performance of the 9-year-old GRC curtain wall to like-new condition.

Prevention is better than cure. Through careful selection of raw materials, mix proportion optimization, and curing regime control, Qinglong Group keeps the incidence of early shrinkage cracks below one in ten thousand. For installed components, regular inspection is essential; a comprehensive crack survey every six months is recommended, with early cracks addressed promptly once found. Proper crack treatment not only restores aesthetics but is also key to ensuring the long-term safe use of GRC.