Correlation of Schmidt Rebound Hardness with Uniaxial Compressive Strength and P-Wave Velocity of Rock Materials


ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, vol.40, no.7, pp.1897-1906, 2015 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 40 Issue: 7
  • Publication Date: 2015
  • Doi Number: 10.1007/s13369-014-1510-z
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1897-1906
  • Keywords: Schmidt hardness, Uniaxial compressive strength, P-wave velocity, Rock material, Empirical relations, ISRM SUGGESTED METHOD, HAMMER, CONSISTENCY, PREDICTION, NUMBER, TESTS
  • Karadeniz Technical University Affiliated: Yes


The Schmidt hammer is widely used for various applications since 1950s due to its simplicity and portability. The purpose of this study was to compare two Schmidt hammer test methods: earlier (R (ISRM-EV)) and revised version (R (ISRM-RV)) of ISRM in terms of estimation capabilities of uniaxial compressive strength (UCS) and ultrasonic P-wave velocity (UPV). Multiple regression analysis was also performed between Schmidt hardness (R) and the ratio of UPV/UCS. A total of 46 rocks [28 volcanic, 8 metamorphic (metabasalt) and 10 sedimentary (carbonate rocks)] were sampled and tested. The validity of obtained coefficients of correlation was confirmed using the correlation analyses. In the present study, the result of the correlation analysis indicated strong relationships between R with UCS, UPV and UPV/UCS ratio. Relationships between R (ISRM-RV) and UCS, R (ISRM-EV) and UPV/UCS ratio, R (ISRM-RV) and UPV/UCS ratio are not significant at a 95 % confidence limit for metamorphic rocks due to the presence of micro-cracks that cause fluctuations in the test results. Other relations are statistically significant according to the correlation analyses with 95 % confidence limit. This study also revealed that UPV/UCS ratios decrease exponentially with increasing R values. It was shown that the ratio of UPV/UCS would be dependent on R for rocks.