Experimental study on mechanical aging properties of self‑swelling anchorage bolt under chemical corrosion

Abstract

ABSTRACT Chemical corrosion is found to influence the strength of grouted rockbolt reinforcement in underground excavations leading to catastrophic. As such, in this paper, we investigated the impact of the chemical corrosion on the new self-swelling anchorage rockbolt, designed by us, during long-term corrosion processes and accelerated corrosion tests with different chemical solutions. The self-swelling anchorage rockbolt uses a self-swelling anchoring agent that hydrates and expands, providing high anchoring force. The impact of pure water, acidic, and salt solutions on the load-bearing capacity and deformability of self‑swelling anchorage bolts was analysed. Additionally, a microscopic XRD component analysis method was used to reveal the changes in microscopic composition of self‑swelling anchoring agents. It was found that after 180 days of accelerated corrosion, pure water and salt solutions had a small effect on the anchorage force of self‑swelling anchorage bolts, whereas the anchorage force of self‑swelling anchorage bolts decreased by 73.4% in an acidic solution with a PH of four. In addition, the deformation capacity of the bolt deteriorates with the time regardless of the chemical solutions. Combined with XRD micro-composition analysis, the effects of different solutions on the mechanical properties of self‑swelling anchorage bolts were as follows in descending order: PH = 4>6% NaSO4>6% NaCl>3% NaSO4 + 3% NaCl>water.