Water absorption test

BlackBar™ – a day from QC lab!

Unlike traditional steel, GFRP rebar properties depend heavily on chemical formulation and manufacturing precision. This is why we test our GFRP rebar in our in-house laboratory — to continuously verify and refine our manufacturing process and ensure consistent quality.

Why water absorption test is critical for GFRP rebar?
The water absorption test is important quality check for glass fibre reinforced polymer (GFRP) rebar. It reveals manufacturing quality, predicts long-term durability and helps detect hidden internal defects before the material reaches the job site.

Quality control & manufacturing assessment
• High absorption often signals internal micro-cracks, air voids or incomplete fiber wetting during production
• Excessive values can indicate incomplete resin cure or a substandard polymer matrix

Durability & structural integrity
• Moisture can cause differential swelling between the polymer matrix and glass fibres, creating internal stresses that lead to cracking and interfacial debonding
• Water also acts as a transport medium for aggressive alkaline ions (OH⁻) from concrete, accelerating chemical degradation of the glass fibres and reducing long-term strength