Fracture strength of warm mix asphalt concretes modified with crumb rubber subjected to variable temperatures

Abstract

This paper was aimed to investigate the effects of crumb rubber, weather condition and loading mode on fracture behaviour of warm mix asphalt (WMA) mixtures. For this purpose, two WMA mixtures were prepared such that the first mixture contained Sasobit (called normal WMA concrete) and the second one contained the same Sasobit but was modified by crumb rubber of recycled tyres (called modified WMA concrete). Fracture experiments were performed on semi-circular bend (SCB) specimens made of the normal and modified WMA concretes under different loading modes of I, II and mixed-mode I/II at different weather conditions of CT (constant temperature) and VT (variable temperature). The results demonstrated that the crumb rubber improved the fracture strength of WMA concretes significantly. Furthermore, both the normal and modified WMA concretes at the weather condition of VT resisted against fracture worse than those at the weather condition of CT, signifying that the weather condition of VT adversely affected the fracture resistance of WMA mixtures. It was also found that the WMA concretes were more vulnerable to fracture under mixed-mode I/II than under pure mode I (or II).

Keywords:

• WMA concrete
• fracture strength
• weather conditions of CT and VT
• mixed-mode I/II
• SCB specimen

Acknowledgments

The authors gratefully acknowledge Dr S-Javid Zakavi and Eng. Siyab Houshmand for their supports in this research program and Mr Fazel Nazafat for his help in preparing the specimens.This support is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.