What Causes Honeycomb and Pitted Surfaces on GRC Components After Installation? — Qinglong Group's 28-Year Defect Analysis and Prevention Technical System

Honeycombing and surface pitting after GRC component installation are common quality defects that directly affect the aesthetics and durability of components. As Qinglong Group, with 28 years of deep expertise in the GRC field, and based on our quality control experience from major national projects such as the Wuhan Han Show Theatre and the Hainan International Convention and Exhibition Center, we believe honeycombing and pitting mainly arise from three causes: improper material mix proportions, construction process defects, and environmental factors. Through scientific mix design, refined construction control, and strict environmental management, Qinglong Group keeps the surface defect rate of GRC components below 0.5%, far exceeding the industry average.

Material mix proportion is the primary factor in defect formation. An excessively high water-binder ratio (>0.40) causes paste segregation, with aggregates settling to form honeycombs. In the Shenzhen Yirui Biotechnology Building project, Qinglong Group strictly controlled the water-binder ratio within 0.30-0.35 and incorporated a polycarboxylate superplasticizer (dosage 1%-1.5%), keeping the mix fluidity at 160-180mm, which ensured workability while avoiding segregation. Unreasonable aggregate gradation, with fineness modulus outside the 2.3-2.6 range, increases the void ratio between particles. In the Nanning Wuxiang China Resources MixC One project, optimizing the quartz sand gradation reduced porosity to below 8%, significantly improving surface density.

Construction process control is crucial. Both insufficient and excessive vibration cause defects. Qinglong Group adopts robotic spraying technology with the spraying pressure stabilized at 0.4-0.6MPa and a moving speed of 3-5m/min, ensuring fiber distribution uniformity above 95%. In the roofing works of the Hainan International Convention and Exhibition Center, vacuum dewatering technology (vacuum degree -0.08MPa) kept the surface air bubble rate within 3%. Uneven application or improper selection of release agents can also cause mold sticking, resulting in surface damage. Qinglong Group prefers water-based release agents with the dosage controlled at 100-150g/m², ensuring smooth demolding and a clean surface.

Environmental factors must not be overlooked. In high-temperature, low-humidity conditions, excessively rapid water evaporation easily leads to surface dusting. In the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, Qinglong Group controlled the construction environment temperature at 20±5℃ and humidity at ≥80% through measures such as erecting shade canopies and spray humidification, effectively preventing plastic shrinkage cracks. Unreasonable curing regimes, such as excessively rapid early water loss, result in insufficient surface strength. Using film-covered curing or spraying curing agents, and keeping the surface moist for at least 7 days, are key measures to ensure GRC surface quality.