Why Is Sea Sand Prohibited in GRC? What Are the Standards for Qualified Silica Sand?

GRC strictly prohibits the use of sea sand, as its high chloride content (0.3%-0.5%) causes fiber corrosion and rusting of metal components. Qualified silica sand must meet: SiO₂ content ≥96%, mud content ≤0.3%, chloride content ≤0.01%, and fineness modulus 1.8-2.2. These requirements ensure GRC durability.

Qinglong GRC uses high-quality silica sand from Zhangzhou, Fujian, with a SiO₂ content of 97.2% and mud content of 0.15%, which is washed and sieved to ensure consistent quality. GRC made with this silica sand, after 10 years of service in coastal areas, was tested to show a chloride penetration depth of only 1.5mm and a strength retention rate of 90%, proving the material's excellent durability.

Hazard Analysis of Sea Sand

High chloride content (0.3%-0.5%) corrodes fibers and metal components; high salt content easily absorbs moisture and causes efflorescence; abundant impurities such as shells affect strength. These hazards must be avoided.

Requirements for Qualified Silica Sand

SiO₂ content ≥96% ensures hardness; mud content ≤0.3% reduces water demand; chloride content ≤0.01% prevents corrosion; fineness modulus 1.8-2.2 optimizes particle grading. These requirements must be met.

Sand Source Selection Recommendations

Prefer river sand or washed manufactured sand; avoid using sea sand or incompletely desalinated sea sand; establish a list of qualified suppliers. These recommendations ensure sand source quality.

Incoming Inspection Control

Test chloride content for every batch of sand; conduct regular sieve analysis to check grading; return any substandard sand immediately. These controls eliminate the use of problem sand.

Strict sand control is a vital part of quality assurance. Qinglong GRC has established a comprehensive sand control system to ensure product durability.