The use of the Schmidt Hammer and Equotip for rock hardness assessment in geomorphology and heritage science: a comparative analysis
Article first published online: 5 JUL 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Earth Surface Processes and Landforms
Volume 36, Issue 3, pages 320–333, 15 March 2011
How to Cite
Viles, H., Goudie, A., Grab, S. and Lalley, J. (2011), The use of the Schmidt Hammer and Equotip for rock hardness assessment in geomorphology and heritage science: a comparative analysis. Earth Surf. Process. Landforms, 36: 320–333. doi: 10.1002/esp.2040
- Issue published online: 21 FEB 2011
- Article first published online: 5 JUL 2010
- Manuscript Accepted: 15 APR 2010
- Manuscript Revised: 1 APR 2010
- Manuscript Received: 4 JAN 2010
- rock strength;
- built environment;
- Schmidt Hammer;
Rapid, field-based measurements of rock hardness are of use in investigating many geomorphological and heritage science problems. Several different methods are now available for taking such measurements, but little work has been done to assess their comparability and strengths and weaknesses. We review here the capabilities of two types of Schmidt Hammer (Classic N type and Silver Schmidt BL type) alongside two types of Equotip (standard type D and Piccolo) for investigating rock hardness in relation to rock weathering on various types of sandstone and limestone, as well as basalt and dolerite. Whilst the two Schmidt hammers and the two Equotips show comparable results when tested at 15 individual sites, interesting differences are found between the Equotip and Schmidt Hammer values which may reveal information about the nature of weathering on different surfaces. Operator variance is shown to be an issue in particular for the Equotip devices, which also exhibit higher variability in measurements and necessitate larger sample sizes. Carborundum pre-treatment also has varying effects on the data collected, depending on the nature of the surface studied. The Equotip devices are shown to be particularly useful on smaller blocks and in situations where edge effects may affect Schmidt Hammer readings. We conclude that whilst each device contributes to geomorphological research, they do not necessarily produce comparable information. Indeed, using Schmidt Hammer and Equotip in combination and looking at any differences in results may provide invaluable insights into the structure of the near-surface zones and the nature of weathering processes. Copyright © 2010 John Wiley & Sons, Ltd.