Title: Measurement of Fiber Content of Steel Fiber Reinforced Concrete by Electra-Magnetic Method
Author(s): Taketo Uomoto and Kazusuke Kobayashi
Publication: Symposium Paper
Appears on pages(s): 233-246
Keywords: fiber content; fiber reinforced concretes; measuring
instruments; metal fibers; quality control.
Increase of steel fiber reinforced concrete structures requires a simple test method for measuring steel fiber content in concrete. The measurement of steel fiber content is considered important as the fiber content is the most important index for quality control of steel fiber reinforced concrete. The prominent test methods which have been presented so far are washing analysis and X-ray image test. Both of these tests are too troublesome to be applied for field tests. Measurement of fiber content using electro-magnetic method is not only applicable to hardened concrete but also to fresh con-crete. The measurement can be done within a few minutes whether the test is performed in laboratories or on the fields. A special electro-magnetic apparatus is made and the problems encountered are investigated. The problems are such as the effects of distribution and orientation of steel fibers, the effects of the distance from the apparatus to the test specimen, etc.. A practical method to measure steel fiber content is clarified and the measured values showed good agreements with the washing analysis. Application of the apparatus for estimation of rupture sections of beams is also investigated.