A non-destructive tool for detecting changes in the hardness of engineering materials: Application of the Equotip durometer in the coastal zone

• The Equotip durometer was applied to rock and concrete exposed to marine conditions.
• Over 20 months, limestone hardness decreased while concrete hardness increased.
• Changes in the hardness of granite were not significant.
• Changes occurred primarily as a result of chemical and biological weathering processes.
• The Equotip is valuable as a non-destructive monitoring tool for engineers.

Non-destructive tools capable of measuring the condition and geomechanical properties of construction materials through time are of considerable value in engineering. Here, the ability of the Equotip durometer (Proceq, type D) to detect changes in the hardness of concrete and rock exposed to marine conditions was tested. Results indicated a progressive loss of hardness for limestone, while concrete hardness increased. Granite showed no significant change. Our results relate to alteration of the materials primarily via chemical and biological weathering. The Equotip is sensitive enough to detect subtle changes in the condition of construction materials over relatively short periods of time.