Quantitative Weathering Assessment of Granite Rock Slope Surfaces in Malaysia Using Image Analysis and CIELAB Color Data: A Case Study

This research improved the traditional method of visually assessing macroscopic weathering by using image analysis based on CIELAB color data input. Focusing on the granite rock slope surface assessment in Malaysia, the current study combined the use of CIELAB colour space and image analysis to develop a rapid preliminary quantitative weathering assessment. The obtained results revealed the increase of a* and b* values with the weathering outcomes. The analysis of 50 measurement points of the studied rock slope revealed that a* and b* were positively correlated (R2 of 0.9027). The results of image analysis further revealed the susceptibility of the major zones (74%) due to structural control and the considerable extent of weathering of the remaining zones (26%) in grades IV–V, which were validated through geological structural assessment and geomechanical testing. This study successfully developed a rapid preliminary quantitative weathering assessment for geotechnical and technical purposes.