Accession Number : ADA265753


Title :   Automated Crack Identification for Cement Paste


Descriptive Note : Final rept. 4 Jun 1990-13 Apr 1993


Corporate Author : KANSAS UNIV LAWRENCE CENTER FOR RESEARCH IN ENGINEERING SCIENCE


Personal Author(s) : Ketcham, Kirk W ; Romero, Francisco A ; Darwin, David ; Gong, Shanglong ; Abou-Zeid, Mohamed N


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a265753.pdf


Report Date : Apr 1993


Pagination or Media Count : 85


Abstract : The development of an automated procedure for the identification of microcracks in cementitious materials is described. The degree and nature of microcracking is measured using backscattered electron images Obtained with an integrated scanning electron microscope/image analysis system. Multiple developed to identify and measure microcracks within the individual phases of cement paste. The procedure is developed to assist in the determination of the roles played by individual phases in cement paste in the formation and propagation of microcracks. Procedures for specimen testing, preparation, imaging, and crack analysis are described, along with a description of the development of the analysis program. The analysis capabilities of the program are demonstrated. The gray level of epoxy-filled cracks in polished cement paste specimens is affected by the atomic number density of underlying and adjacent phases. As a result, cracks cannot be identified based on gray level alone. Epoxy-filled cracks in polished cement paste specimens can be identified of geometric requirements; and combined procedures that establish the floor of a crack, minimum gradient and gray level adjacent to cracks, and minimum differences in gray level between the floor of a crack and adjacent solid phases provide a reproducible and consistent technique for crack identification in cement paste.... Backscattered electron imaging, Backscattering coefficient, Calibration, Cement paste, Cracking, Epoxy impregnation, Gray levels, Hydration, Image acquisition, Image analysis.


Descriptors :   *DETECTION , *CEMENTS , *MICROCRACKING , *ADHESIVES , SCANNING , COMPUTER PROGRAMS , BACKSCATTERING , ATOMIC PROPERTIES , HYDRATION , IMPREGNATION , SOLID PHASES , DETERMINATION , IMAGES , IDENTIFICATION , ELECTRON MICROSCOPES , PROPAGATION


Subject Categories : Adhesives, Seals and Binders
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE