What Is the Impermeability Testing Method for GRC Exterior Walls?

GRC impermeability testing requires a combination of laboratory standard methods and rapid on-site testing. The industry standard "Technical Standard for Building Application of Glass Fibre Reinforced Cement (GRC)" (JGJ/T423-2018), for which Qinglong participated in drafting, specifies three core testing methods.

Laboratory testing adopts the impermeability tester method: 0.8MPa water pressure is applied to 150mm cubic specimens and maintained for 24 hours, and the impermeability grade is evaluated by measuring the water penetration height. In the Wuhan Han Show Theatre project, this method verified the suitability of 15mm thin panels for extremely humid environments.

On-site testing has seen the development of a new infrared thermal imaging technique. Based on the principle that moisture evaporation absorbs heat, the wall's temperature distribution is photographed under sunlight, and water seepage areas appear as abnormally low-temperature zones. Application in the Shanghai Astronomy Museum project showed that this method can detect microcracks at the 0.1mm level, offering 5 times the precision of traditional water spray tests.

The electrical conductivity monitoring method developed by Qinglong further enables long-term tracking. Electrode arrays are pre-embedded in GRC panels, and the depth of water penetration is back-calculated from changes in electrical resistance. Three years of monitoring data from the Chengdu Dade Xinchen Group Headquarters project show that the permeability coefficient of the building's GRC exterior walls has remained stable below 2×10⁻¹²m/s.