Multiscale Crack Fundamental Element Model for Real-World Pavement Crack Classification

High-resolution 2D intensity and 3D range data are available to support pavement crack detection and classification. However, crack classification based on actual distress protocols specified by different state departments of transportation (DOTs) still remains a challenge because of the complexity of real-world crack classification. In addition, developing crack performance measurements that can be used consistently among different state DOTs is another challenge. The objective of this paper is to propose a novel crack fundamental element (CFE) model based on a multiscale topological crack representation. Based on the observation of real-world pavement crack characteristics, the proposed multiscale CFE model consists of (1) a CFE along with its geometrical properties that can be represented consistently at different scales, (2) connecting and expanding operations to cluster CFEs from a small to a large scale, and (3) the topological crack representation inside each CFE, including fundamental and aggregated crack properties and CFE geometrical properties. The proposed multiscale CFE model provides crack properties that enable researchers to develop innovative crack classification methods to characterize cracks at different scales and flexibly model crack classifications specified by different state DOTs. In addition, it also delivers the rich and invariant crack properties that enable researchers to develop standardized crack performance measurements. A real-world load cracking classification application based on the logistic regression method has also been developed and tested using the actual pavement data collected near Savannah, Georgia to demonstrate the use of the crack properties extracted from the proposed model. Results show that the proposed model is promising for developing real-world crack classification applications. Finally, future research is recommended. (C) 2014 American Society of Civil Engineers.