Effects of variation in the particle size of the rock abrasion powder and standard rotational speed on the NTNU/SINTEF abrasion value steel test

Ten potentially abrasive rock samples selected from various locations of Pakistan covering igneous, metamorphic and sedimentary rocks were subjected to a comprehensive laboratory testing program. The experimental work includes the NTNU/SINTEF abrasion value steel (AVS) and Sievers' J-miniature drill (SJ) tests accompanied by CERCHAR and LCPC rock abrasivity tests. The results of SJ tests and AVS tests were further utilized to compute the cutter life index (CLI), which estimates the life of tunnel boring machine (TBM) disc cutter rings in boring hours. In this research, a comparative study was performed on an NTNU/SINTEF rock abrasivity device by varying the particle size of rock abrasion powder and rotational test speed of the steel disc. The NTNU/SINTEF AVS test results showed a gradual decrease in abrasivity with the corresponding decrease in grain size of test fractions. An increase in the wear of the test piece was observed at a test speed of 10rpm as compared to the standard test speed of 20rpm. Relevant correlations of CLI, SJ-value and AVS with CERCHAR abrasivity index (CAI) and LCPC abrasivity coefficient (ABR, g/t) were also discussed.