Strength Development of Shotcrete in Compressed Air Pressurised Underground Environment

Shotcrete and compressed air are often utilised for providing temporary support in tunnel excavation. On occasions of concurrent application of shotcrete and compressed air, there would be concerns of the quality of concrete sprayed within pressurised space, as well as the strength development of shotcrete in pressurised environment. To address these concerns, field experimentation of the shotcrete strength development under compressed air pressure was conducted, and the results are reported in this paper.