| Influence of Fracture Surface Roughness Characteristics
on the Specific Fracture Energy of Concrete as a Function of Specimen and
Aggregate Size
Primary Researcher:
Roberto
Ballarini
Department of
Civil Engineering
Case Western Reserve University,
Cleveland,
OH 44106, USA
E-mail: rxb7@po.cwru.edu,
Tel. (216) 368-2963
National
Science Foundation award information
Abstract:
The influence of the microscale and concrete compressive
strength on the fracture energy per unit crack surface area will be evaluated
by studying the
roughness characteristics of
a fracture surface, such as the surface roughness index, fractal
dimension and wavelength content. The major objectives of this research
are:
a) to perform 3-point bending tests under CMOD control
on concrete beam specimens of three sizes with three maximum aggregate
sizes and three concrete compressive strengths and determine the roughness
characteristics of the fracture surfaces, that is the roughness index,
fractal dimension, and Fourier amplitude spectra for each fracture surface
b) to study the roughness characteristics of the fracture
surfaces and to evaluate their dependence on the maximum aggregate size
and concrete compressive strength and their influence on the "load vs.
load-point-displacement" response and the specific fracture energy.
c) to develop a micromechanics-based semi-empirical analysis,
wherein the apparent toughness will be calculated based on the given roughness
characteristics of the observed crack paths and aggregate size. This research
program will be undertaken through a university- state-industry collaboration.
The results will improve the methods of specification and evaluation of
the performance of normal and high strength concrete resulting in more
efficient designs.
Acknowledgment: The authors
acknowledge support from the National Science Foundation's Grant CMS 9713997
CWRU Department of Civil Engineering
Communication
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