Comprehensive tests and quasi-brittle fracture modeling of light-weight foam concrete with expanded clay aggregates

Abstract

Expanded Clay Foam Concrete (eC-FC) is a light-weight foam concrete with expanded clay aggregates, which is an important class of building materials, yet its tensile strength ft and fracture toughness KIC cannot be easily measured using small test samples due to its highly heterogeneous microstructures. This study presents a simple closed-form model for quasi-brittle fracture of heterogeneous solids confirmed by comprehensive three-point-bend (3-p-b) test results from 168 notched eC-FC specimens with eight group sample designs. One tensile strength ft was determined from individual group or all from the model initially developed for normal concrete, proving both the trans-granular fracture in eC-FC and inter-granular fracture in normal concrete can be modeled by this fracture model. Unidirectional compressive tests of the eC-FC were also performed, and tensile strength ft estimated from the compressive strength fc is consistent with ft from 3-p-b tests. Fracture toughness KIC was determined from the model using tensile strength ft and the average aggregate size G.