Title:
Size Effect and Influence of Aggregate Roughness in Interface Fracture of Concrete Composites
Author(s):
Uwe Trende and Oral Buyukoturk
Publication:
Materials Journal
Volume:
95
Issue:
4
Appears on pages(s):
331-338
Keywords:
aggregate roughness; brittleness; fracture toughness curves;
high-strength concrete; interface fracture properties; mixed mode fracture;
size effect
DOI:
10.14359/375
Date:
7/1/1998
Abstract:
The size effect exhibited by interface fracture and the influence of aggregate roughness on mortar-aggregate interface fracture parameters are investigated. The concrete composites studied are bi-material systems consisting of a granite inclusion embedded in high-strength mortar. Newly developed compact sandwiched beam specimens of three different sizes are tested in Pure Mode I and in mixed mode (opening and shear) loading conditions. Three different roughnesses of the aggregate inclusion are used: smooth, sandblasted, and flamed. The critical interface fracture energy release rates and corresponding size effect parameters are calculated from the fracture loads of the composites. The size effect data are correlated to an existing size effect law; strong size effects are observed indicating the brittle nature of interfaces in cementitious materials. Parametric analysis shows that for a given loading condition the critical interface fracture energy release rate increases with rougher aggregate surfaces for both Mode I and mixed mode tractions. Similarly, for a given aggregate roughness, the interface fracture energy release rate is shown to increase with greater shear loading.