What Causes Honeycombing and Pitted Surfaces on GRC Components After Installation? An In-Depth Analysis of Qinglong GRC Surface Quality Defects

Surface quality defects such as honeycombing and pitted surfaces on GRC components result from the combined effect of multiple factors, including improper material mix ratios, lax construction process control, or poor curing conditions. As a professional manufacturer with 28 years of industry experience, Qinglong GRC has systematically summarized the seven key factors causing surface defects and their prevention measures, based on quality problem analysis from numerous engineering cases.

In a commercial complex project in Shenzhen, localized pitted surfaces appeared on the surfaces of some GRC decorative columns. Through site inspection and laboratory simulation analysis, the root causes were identified as: excessive fiber content (up to 5.2%) with uneven distribution, forming local agglomeration; lax water-cement ratio control, with actual values fluctuating between 0.33 and 0.38; and unreasonable vibration process parameter settings, with both over-vibration and missed vibration occurring. By adjusting the mix ratio (reducing fiber content to 4.5%) and optimizing the vibration process (adopting variable-frequency vibration with duration controlled at 90±10 seconds), the defect rate was reduced from an initial 12% to 0.8%.

Analysis of Material Mix Ratio Factors

A water-cement ratio that is too high (>0.38) causes slurry segregation and aggregate settlement; fiber content exceeding the limit (>5%) easily causes agglomeration, hindering slurry flow; excessive water reducer causes bleeding, forming surface water marks. The optimal mix ratio should be determined through trial mixes, with the water-cement ratio controlled at 0.32-0.36 and fiber volume content at 4%-4.8%.

Key Points of Production Process Control

Insufficient mixing time (<240 seconds) results in uneven fiber dispersion; inadequate compaction or over-vibration causes aggregate segregation; misadjusted spraying process parameters (air pressure, distance) lead to insufficient compaction. Process parameters must be strictly monitored: mixing time of 240-300 seconds, with vibration continuing until slurry appears on the surface.

Mold and Release Agent Factors

Mold surface roughness exceeding the standard (Ra>3.2μm) replicates defects; uneven application or improper selection of release agents affects surface texture. Mirror-finish steel molds or high-quality GRP molds should be used, with release agent spray thickness of 20-30μm.

Curing Condition Control Standards

Excessively rapid early water loss leads to surface dusting; excessive temperature differences (>15℃) cause plastic shrinkage cracks. Adopt film-covered curing with ambient humidity ≥90% and temperature of 20±5℃.

Prevention of surface quality defects requires systematic measures. Qinglong GRC has established 136 quality control points to achieve refined full-process control, with the product first-time acceptance rate reaching 99.2%.