Title: Global Size Effect Model—A Variant for Type-2 Size Effect Model

Author(s): Dong Li, Liu Jin, and Xiuli Du

Publication: Materials Journal

Volume: 118

Issue: 3

Appears on pages(s): 117-130

Keywords: cementitious system; maximum aggregate size; morphological structure; quasi-brittle fracture mechanics; size effect

DOI: 10.14359/51730425

Date: 5/1/2021

Abstract:
The concept of global size effect theory from material level to structural level is raised. The material level is described by a Universal Morphological Model (UMM) that accounts for the size effect behaviors introduced by the mixture variables of concrete, whereas the structural level is linked to the size effect theory based on quasi-brittle fracture mechanics. First, the UMM that is eligible for the description of material-level size effect is established and verified. Parametric study on the UMM shows that the mechanical properties of concrete are insensitive to the maximum aggregate size (MAS) at a critical interface crack index ηc. Secondly, by introducing the UMM into the formulation of structural-level size effect, a global size effect model (GSEM) expressed as a variant for the Type-2 size effect model (SEM) is proposed. Parametric study on the GSEM shows that the properties and the scales of mesostructures have significant influences on the size effect behaviors of concrete at the structural level. The critical interface crack index ηc determined by the UMM should receive sufficient attention in large-scale structural concrete design in practice.