What Causes Honeycomb and Pitted Surfaces After GRC Components Are Installed?

Honeycombing and pitted surfaces appearing after GRC component installation stem mainly from three areas: material mix ratio, production process, and installation operations. With 28 years of production and construction experience, Qinglong has kept the occurrence rate of this problem below 0.5% through standardized controls, achieving smooth, defect-free surfaces on multiple high-end projects.

1. Improper Material Mix Ratio: Inherent Quality Risks

Unreasonable material combinations are the root cause of honeycombing and pitted surfaces. Aggregate gradation issues: oversized aggregate particles (>5mm) or discontinuous gradation result in high porosity inside the GRC, forming honeycombs; Qinglong uses 0.15-0.6mm continuously graded quartz sand, reducing porosity by 30%. Water-cement ratio imbalance: when the water-cement ratio is >0.45, the slurry bleeds severely and the surface is prone to sanding and pitting; when it is <0.35, the slurry has poor flowability and cannot easily fill mold gaps; Qinglong precisely controls the water-cement ratio between 0.38 and 0.42. Uneven fiber distribution: agglomeration of alkali-resistant glass fibers or insufficient dosage (<2.0%) prevents an effective skeleton from forming, and loose honeycombs easily appear in localized areas; Qinglong uses dual-axis forced mixing, achieving a fiber distribution uniformity of 98%.

2. Production Process Defects: Loss of Control During Forming

Improper operations during production directly cause surface defects. Insufficient vibration: manual vibration or low-frequency vibration (<1500 times/min) cannot expel air bubbles, and trapped bubbles form pitted surfaces; Qinglong uses high-frequency vibration equipment (≥2500 times/min), raising the bubble expulsion rate by 80%. Mold issues: rough mold surfaces, incomplete cleaning, or failure to apply release agent cause the GRC surface to stick and sand; Qinglong molds are made of GRP with a surface roughness ≤0.05mm, and a dedicated water-based release agent is selected. Improper casting method: excessive single-pour thickness (>50mm) causes the slurry to settle and aggregates to accumulate, forming honeycombs at the bottom; Qinglong uses layered casting (each layer ≤30mm) with vibration compacting layer by layer.

3. Improper Installation and Post-Treatment: Secondary Damage

Installation and curing stages can aggravate surface problems. Inadequate substrate cleaning: dust, oil stains, or standing water on the installation substrate result in weak bonding between the GRC and the substrate, with hollowing and honeycombing easily appearing at edges; Qinglong thoroughly cleans the substrate before installation and applies a bonding agent to enhance adhesion. Untimely curing: failure to cover and keep the surface moist promptly after demolding (<12 hours) causes rapid evaporation of surface moisture, forming drying-shrinkage pitting; Qinglong uses constant temperature and humidity curing (humidity ≥90%, over 7 days). Non-standard repairs: when repairing localized defects, repair materials incompatible with the original GRC cause color differences or secondary sanding; Qinglong uses repair slurry with the same mix ratio, achieving surface flatness ≤1mm after repair.