Image-Analysis-Based Measuring of Lateral Deformation of Hardening Concrete

Abstract

At present, there is no special testing method for measuring the lateral deformation of solidifying and hardening concrete. Contact methods, which are used for already hardened concrete, are not suitable due to either their incapability of attaching the measuring equipment to the surface of a specimen or the lack of adhesion in case of application of embedded strain gauges. The use of laser sensors also is not suitable for application since the longitudinal deformation of hardening concrete is quite large, which requires some mobile attachment of the laser sensor so that it can follow the targeted spot with progressing longitudinal deformation. An optical method where an image is captured with a high-resolution CCD camera is relatively easy and nowadays also inexpensive. Capturing an image solves the part of acquiring test data on the lateral deformation, however, conversion of image data to lateral deformation measurement requires an adequate method, which is described in this paper.