Title: X-Rays for Study of Internal Structure and Microcracking of Concrete

Author(s): Floyd O. Slate and Stanley Olsefski

Publication: Journal Proceedings

Volume: 60

Issue: 5

Appears on pages(s): 575-588

Keywords:

DOI: 10.14359/7869

Date: 5/1/1963

Abstract:
Use of x-radiography for studying the internal structure of concrete is described and discussed. Thin slices of concrete are sawed out of a mass and irradiated. Radiographs provide a permanent record for further study. Miscrocopic examination of stained specimens is used as a companion method and as a check. . Both methods revealed cracks formed during drying (and possi ble carbonation), almost exclusive1 Y at th e interfaces between aggregate andes. These mortar, predominantly on larger aggregate cracks were observed in concrete not subjected to any prior loading. In concrete subjected to large compression strains, bond cracking at the interfaces was observed to be areatlv increased, with additional cracks through mortar- bridging between bond cracks. Internal segregation of unhardened concrete is also observable (on the hardened concrete) by this technique. The x-ray‘technique described is a powerful new tool for study of the internal structure, and changes in the internal structure, of concrete.