Influence of concrete composition on the characterization
of fracture surface
An Yan
*
, Ke-Ru Wu, Dong Zhang, Wu Yao
State Key Laboratory of Concrete Materials Research, Tongji University, Siping Road 1239, Shanghai 200092, People’s Republic of China
Received 1 June 2001; accepted 10 November 2001
Abstract
An experimental method based on laser triangulation was used to measure the 3-D profile of fracture surface of concrete. The
projective-covering method was established to determine the fractal characteristics of fracture surface. Based on the experiment, the
influence of composition of concrete on the fractal dimension, including water–binder ratio, maximum aggregate size and aggregate
type, was investigated. The variation of fractal dimension with the material composition was also analysed to make further un-
derstanding of fracture mechanism of concrete.
Ó 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Fracture surface; Fractal dimension; Composition of concrete
1. Introduction
Due to roughness and irregularity of crack inside the
concrete materials, more energy is required to form new
fracture surface. Mindess [1,2] has ever pointed out that
this extra energy should be taken into consideration to
make the fracture model more reasonable. However, due
to the complexity of fracture surface, to date, the fracture
surface is still idealized as 2-D plane in the fracture me-
chanics research of concrete materials. The fracture
surface, as important post-mortem evidence, helps to
reveal the micro-mechanism of fracture and plays an
essential part in the evaluation of fracture mechanics
properties of cementitious materials.
Many researchers have paid attention to the impor-
tance of fracture surface [3–6]. The researches on the
fracture surface are made in an attempt to establish the
relationship between characterization of fracture surface
and mechanical behaviour. The characterization of
fracture surface is determined mainly by composition of
concrete materials and loading conditions so that the
relationship between composition of concrete and char-
acterization of fracture surface is important to study the
mechanical behaviour of concrete. However, there are
few systematic reports on the influence of concrete
composition on the fracture surface. In our previous
paper [7], the laser triangulation method was used to
measure the fracture surface to improve our under-
standing of the failure mechanism of concrete and to
measure fracture parameters more precisely. In this
paper, based on the information of fracture surface
achieved, the project-covering method is employed to
determine the fractal dimension of fracture surface. The
relationship between fractal dimension and materials
composition is investigated to provide evidence for
further understanding of fracture process of concrete
materials.
2. Experimental procedures
2.1. Raw materials and mix proportion
Different material compositions of concrete, includ-
ing water–binder ratio, maximum aggregate size and
aggregate type, were considered in this study in order to
investigate the relationship between fractal dimension
and composition of concrete. The controlled mix pro-
portion was shown in Table 1, named by HPC–X–Y–Z,
where X is the water–binder ratio, Y is the maximum
*
Corresponding author. Tel.: +86-21-659-8-2412; fax: +86-21-6598-
3465.
E-mail address: yanank@hotmail.com (A. Yan).
0958-9465/03/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved.
PII: S 0 9 5 8- 9465(02)00004-5
Cement & Concrete Composites 25 (2003) 153–157
www.elsevier.com/locate/cemconcomp