Durability Assessment of Glass FRP Solid and Hollow Bars (Rock Bolts) for Application in Ground Control of Jurong Rock Caverns in Singapore

Abstract

This study was conducted to investigate the durability of two types of vinyl-ester/glass fiber-reinforced polymer (GFRP) rock bolts [solid and hollow (tubular) GFRP bars] that were subsequently used for ground control of the Jurong rock caverns in Singapore. The testing program aimed to assess the long-term durability characteristics of unstressed hollow and solid GFRP rock bolts subjected to a saline solution (simulating the subsea cavern water of the Jurong rock caverns in Singapore) and predicting their long-term tensile strength in such environments. The study simulated rather aggressive conditions by immersing the hollow and solid GFRP bars (rock bolts) in the solution at different elevated temperatures (20, 40, and 50°C) in climate chambers for different exposure times of 1,000, 3,000, and 5,000 h. Arrhenius plots were applied to the test results, extrapolating the project’s life to 50 years at a mean annual temperature (MAT) of 32°C. The predicted tensile strength at a MAT of 32°C is 96.8 and 97.3% for a service life of 50 years for solid and hollow GFRP bars, respectively. Based on the obtained results, the tested GFRP rock bolts were recommended as alternatives to stainless-steel rock bolts and successfully used as ground control in the Jurong rock caverns in Singapore.