Study on pitting mechanism of rebar rockbolt in highly-mineralized mine water

Abstract

Corrosion and abnormal failure of rockbolts often occur in the mine water and complex environment.It is found that local corrosion such as pitting is usually the main origin of corrosion failure.Pitting process and mechanism in simulating corrosive mine water of four rockbolts were tested and analyzed with a comprehensive method including metallographic examination, electrochemical experiments and video microscope.The results showed that rockbolt steel was prone to pitting corrosion due to the inclusions.The pitting mechanism was as follows: The inclusions were preferentially dissolved, producing granular corrosion products and forming interface grooves.Local acidification in grooves accelerated the dissolution and exfoliation of matrix and inclusions, which produced etching pits.The acceleration effect of interface grooves on corrosion was verified by the comparison of polarization curves of different electrodes.

Keywords

• highly-mineralized mine water
• rebar rockbolt
• pitting
• inclusion
• interface groove