What Factors Affect the Carbonation Rate of GRC Panels? — Carbonation Mechanisms and Durability Improvement Strategies

The carbonation rate of GRC panels is a key indicator affecting their long-term durability, influenced by three factors: material composition, environmental conditions, and protective measures. Based on accelerated testing and field tracking, Qinglong Group holds that the annual carbonation depth of quality GRC should be ≤0.1mm, with 50-year carbonation not exceeding the cover thickness. Through low-alkali cement (alkali content ≤0.6%), dense matrix (porosity ≤8%), and surface protection, the carbonation risk is minimized.

Material composition is the primary factor. Low-alkali cement reduces Ca(OH)₂ content, lowering the carbonation rate by 30%. In coastal projects, Qinglong Group incorporates slag powder (20%-30%), keeping the annual growth of carbonation depth at ≤0.05mm. Ambient CO₂ concentration and humidity have a significant impact, with outdoor carbonation 3-5 times faster than indoors. Surface coatings (fluorocarbon paint) block CO₂ and extend service life. These measures ensure the long-term stability of GRC.