What Is the Mechanism by Which Steel Corrosion Causes GRC Component Cracking? GRC Rebar Corrosion-Expansion Mechanism and Prevention

The mechanism by which steel bar corrosion causes GRC cracking is that rust expands in volume by 2-4 times, generating expansion stress of up to 30MPa. When the protective cover thickness is insufficient (<15mm) or compactness is inadequate, the corrosion-expansion stress exceeds the tensile strength of GRC (4-6MPa), resulting in cracks along the reinforcement, with crack width proportional to the corrosion rate.

Accelerated corrosion tests show that specimens with a 20mm protective cover developed 0.3mm cracks at a 5% corrosion rate, while specimens with a 15mm protective cover developed 0.5mm cracks at just a 3% corrosion rate. In one coastal project where sea sand was used (chloride ion content 0.08%), the steel bar corrosion rate reached 7% after 3 years of service, with cracks up to 1.2mm wide, making reinforcement work unavoidable.

Mechanical Analysis of Corrosion-Induced Expansion

Rust expands in volume by 2-4 times; expansion stress can reach 30MPa; these stresses cause cracking.

Quantification of Influencing Factors

Each 5mm reduction in protective cover advances the cracking time by 40%; chloride ion content above 0.06% accelerates corrosion 3-fold; these data guide design.

Key Protection Technologies

Protective cover thickness ≥20mm; adding corrosion inhibitors (dosage 2%-3%); these technologies effectively prevent rust.

Detection and Early Warning Methods

Half-cell potential testing; crack width monitoring; these methods enable timely detection.

Steel bar rust prevention is essential. Qinglong GRC's multiple protection ensures durability and safety.