Self-compacting high-performance fiber concrete for foundations

Abstract

An investigation was executed into the applicability of self-compacting
high performance fiber concrete in foundations. The applied concrete has
a concrete cube strength of about 110 MPa and contains 60 kg/m3 hooked-end steel fibers (LF = 30 mm, DF = 0.38 mm).
This publication consists of two parts: (1) Experimental assessment and
verification of design rules and (2) assessment of fiber orientation
and distribution. In the first part, experiments are described which
were carried out to determine the pre- and post-cracking strength
properties, the shear resistance of short beams, the anchorage length of
rebars, and the shear capacity of foundation slabs supported on piles.
The test results were used for a verification and extension of design
rules for fiber reinforced concrete (FRC) found in the fib Model
Code 2010. The application of the FRC developed can lead to substantial
savings in concrete and reinforcing steel. In the present second part,
cross-sections of two slabs and a beam of this testing series have been
analyzed with regard to fiber orientation and distribution. An image
analysis, executed on 111 concrete areas, indicates that a preferred
fiber orientation could not be identified throughout the assessed
elements. The data supports the conclusion of a good fiber distribution
as well; a strong correlation was obtained for the data set of full
images between measured and theoretical relation of fiber orientation
and fiber density.