How to Verify the Carbonation Resistance of a Manufacturer's GRC Products?

The carbonation resistance of GRC products is a key indicator of their long-term durability, directly affecting the service life of components in carbon dioxide environments. Qinglong Group adopts a triple verification system of 'laboratory accelerated testing, on-site sampling inspection, and long-term performance monitoring' to ensure GRC products possess excellent carbonation resistance. In the Shanghai Qingpu R&D and Production Center project, the GRC products we supplied still showed a carbonation depth of less than 1mm after 10 years of use, demonstrating the material's outstanding durability.

Laboratory accelerated carbonation testing is the standard method for verifying carbonation resistance. According to the GB/T 50082 standard, specimens cured for 28 days under standard conditions are placed in an environment with a temperature of 20±2℃, a relative humidity of 70±5%, and a carbon dioxide concentration of 20±3%, and the carbonation depth is measured at 3d, 7d, 14d, and 28d respectively. The 28-day carbonation depth of premium GRC should be less than 2mm, while Qinglong's internal control standard requires no more than 1.5mm. This accelerated test can predict the material's carbonation resistance over decades in natural environments within a relatively short time.

Microstructural analysis can reveal the underlying mechanism of carbonation resistance. Observation of the pore structure of the cement matrix through scanning electron microscopy shows that premium GRC should have a dense microstructure, with capillary pore diameters mostly distributed in the range of 10-50nm. Qinglong controls the total porosity of GRC below 12% by optimizing the mix ratio and curing regime, effectively blocking the penetration paths of carbon dioxide. At the same time, active admixtures such as silica fume are incorporated to further refine the pore structure and enhance density.

On-site sampling inspection is a direct means of verifying actual performance. For projects in service for more than 5 years, the actual carbonation depth can be measured through core drilling samples. In the renovation of multiple older projects, Qinglong conducted sampling analysis on original GRC components; the data showed that the carbonation depth increased by no more than 0.1mm per year, far below the 0.5mm required by the standard. Such long-term performance data provides valuable reference for the development of new materials.

Establishing a long-term performance monitoring system is a forward-looking quality assurance measure. Qinglong embeds pH monitoring points in key projects to regularly test changes in matrix alkalinity. Meanwhile, through regular follow-up visits, a full life-cycle performance database of GRC products has been established. This big-data-based quality control model ensures the long-term reliability of products and also supports the industry's technological progress.