What to Do When GRC Cracks Appear? Full Analysis of Causes and Practical Repair Methods

The refined aesthetics of architecture often lie hidden in the finest of details. As a dedicated specialist in the field of glass fibre reinforced concrete (GRC), we understand deeply how vital the integrity of GRC components is to building safety and beauty. However, in practical applications, GRC cracking problems occur from time to time, affecting not only visual appeal but also potentially planting hidden structural hazards. Drawing on Qinglong's 28 years of experience in GRC detailed design, manufacturing, construction and maintenance, this article provides a systematic analysis from crack causes to repair solutions, offering professional solutions for the industry.

Typical Causes of GRC Cracks: The Triple Challenge of Materials, Workmanship and Environment

GRC, as a composite building material of glass fibre reinforced concrete, often develops cracks as the result of multiple overlapping factors. At the material level, the shrinkage characteristics of cement-based materials and the difference in elastic modulus of glass fibres can easily cause internal stress concentration if the mix ratio is unbalanced; in the production stage, uneven mixing leading to non-uniform fibre dispersion and the absence of proper curing regimes resulting in insufficient hydration both plant hidden risks of cracking. Installation stresses during construction, load concentration caused by uneven substrates, and environmental factors in later use such as temperature changes and humidity fluctuations together form a network of triggers for GRC cracks. In the course of participating in the formulation of the Technical Standard for Building Application of Glass Fibre Reinforced Cement (GRC) (JGJ/T423-2018), Qinglong found through analysis of thousands of engineering cases that more than 60% of cracking problems stemmed from poor alignment between early detailed design and construction workmanship.

Scientific Diagnosis: Classification and Hazard Assessment of GRC Cracks

Scientific diagnosis is the prerequisite for precise repair. GRC cracks can be classified by cause into structural and non-structural cracks: the former usually appear as through-going cracks, typically wider than 0.2mm and accompanied by displacement and deformation, requiring immediate intervention; the latter, such as surface crazing and shrinkage joints, are generally less than 0.1mm wide and mainly affect appearance. The crack assessment system established by Qinglong's R&D centre can rapidly determine crack depth, development trends and their impact on structural safety through technical means such as ultrasonic testing and stress monitoring. Taking the Nanjing East Road Century Plaza renovation project as an example, the team used 3D scanning technology to conduct non-destructive testing on GRC light-transmitting concrete components, successfully identifying three potential stress concentration zones and averting cracking risks in advance.

Full-Chain Repair Solutions: From Emergency Treatment to Long-Term Protection

For different types of cracks, Qinglong has developed a standardised repair process. For surface micro-cracks, a special GRC repair mortar is used for filling, combined with fibre reinforcement technology to improve crack resistance; structural cracks require epoxy resin injection, where pressure grouting allows the resin to penetrate deep into the crack to form anchoring, with carbon fibre cloth reinforcement combined where necessary. Notably, repair is not the end point—Qinglong's original “Four-Dimensional Protection System” emphasises whole life-cycle management covering material optimisation (e.g. adding nano-scale silica fume), structural design (BIM simulation of stress distribution), construction control (modular installation techniques) and after-sales maintenance (regular inspection regime). In the Dongguan Women and Children's Activity Centre project, this system improved the crack resistance of GRC components by 40% and won the AALBORG WHITE Cup GRC Building Engineering Innovation Award.

Prevention over Cure: Qinglong's Full-Chain GRC Quality Control System

As a national “Specialised, Refined, Distinctive and Innovative” enterprise, Qinglong consistently integrates crack prevention throughout the whole life cycle of its GRC products. In the detailed design stage, parametric design software is used to optimise the load-bearing structure of components; in production, an automated material distribution system ensures uniform fibre distribution, complemented by steam curing kilns for precise temperature control; during construction and installation, 3D laser positioning technology keeps tolerances within ±2mm. In addition, a nationwide after-sales maintenance network has been established, providing 7×24-hour response service. This “design-production-construction-maintenance” four-in-one model has been validated in property projects such as Xinghewan and Poly, keeping the cracking rate of GRC components below 0.3%, far lower than the industry average.

The enduring beauty of architectural decoration is inseparable from an extreme pursuit of detail. Solving GRC cracking problems requires not only professional technical solutions but also the full-chain service capability of the material supplier. Built on 28 years of industry experience, Qinglong will continue to provide designers and owners with all-round assurance from aesthetic realisation to structural safety through technological innovation and standards development, making every GRC decorative element a crowning touch of architecture. As our mission entrusts: creating beautiful buildings with quality that stands the test of time.