Accession Number : ADA141788

Title :   Applications of the Scanning Electron Microscope to Concrete Failure (Axial, Biaxial, and Dynamic).

Descriptive Note : Final rept. 1 Sep 80-31 Aug 83,

Corporate Author : STEVENS INST OF TECH HOBOKEN N J

Personal Author(s) : Derucher,K

PDF Url : ADA141788

Report Date : 05 Mar 1984

Pagination or Media Count : 101

Abstract : The major objective was to directly observe the formation and/or propagation of microcracks in concrete (plain and reinforced) both before and after applications of axial, biaxial, and dynamic stress fields. As part of this objective; procedures, techniques, apparatus, and equipment were developed and/or modified for the study of concrete fracture utilizing the Scanning Electron Microscope (SEM). In addition, information regarding microcracks, propagation of these microcracks (concrete failure), aggregate shape, plain and reinforced concrete, the sum effect of various stress fields, and the ultimate strength of concrete was found. Information regarding microcracks, aggregate shape, plain and reinforced concrete, the sum effects of various stress fields, and the ultimate strength of concrete was found for concrete containing blended cements. Concrete may fail from applied service loads or applied stress fields whether they are axial, biaxial, or dynamic. Also, concrete may fail as a result of volume changes such as the hydration of the cement paste leading to the shrinkage microcracks or to various cycles of wetting and drying or temperature variations (freezing and thawing). Thus, a model previously developed was investigated and the equations developed were found to be appropriate.

Descriptors :   *Concrete, *Failure, *Electron microscopes, *Electronic scanners, Microcracking, Reinforced concrete, Biaxial stresses, Stresses, Fracture(Mechanics), Strength(Mechanics), Cements, Hydration, Shrinkage, Freezing, Thawing, Drying, Wetting

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE