Experimental Investigation on Damage Behavior of Polypropylene Fiber Reinforced Concrete under Compression

Lihua Xu,Biao Li,Xiaoxiao Ding,Biao Huang,Yin Chi,Yuchuan Shi,Changning Li

doi:10.1186/s40069-018-0302-3

Abstract

This paper presents an experimental investigation on the stress–strain behavior and the damage mechanism of polypropylene fiber reinforced concrete (PFRC) under monotonic and cyclic compression. Fifty-four specimens for different fiber volume fractions and aspect ratios were tested. Acoustic emission (AE) technique was used to monitor the damage progression. The damage mechanism of concrete was analyzed based on the AE parametric analysis. The results show that the incorporation of polypropylene fiber (PF) has a positive effect on the monotonic and cyclic behaviors of concrete, especially for the post-cracking branch. The toughness and ultimate strain are enhanced and the performance degradation in terms of elastic stiffness and strength is alleviated by the addition of PF. However, PF has little influences on the plastic strain, and the damage process of concrete is mainly driven by the envelope strain. The effect of fiber volume fraction on the cyclic behavior of concrete shows more pronounced than that of aspect ratio. In addition, it is found from AE results that the damage, closely related to AE events, has a quick evolution just after the peak stress, with the AE hits having a concentrated release. The total amount of AE hits increases with increasing fiber volume fraction due to fiber pullout and sliding, while the concrete with fiber aspect ratio of 280 reaches the largest amount. Meanwhile, as substantiated by AE, the failure of PFRC shows an obvious shear mode, with shear cracks dominating the damage progression. Finally, a damage elasto-plastic model is developed to predict the monotonic and cyclic responses of PFRC and the prediction yields a fairly close estimation with experimental results.

Highlights

In recent years, polypropylene fiber reinforced concrete (PFRC) has been experiencing a rapid development and its application has become widespread in civil engineering fields, such as constructions, bridges, surface of pavements, tunnel linings and hydraulic structures (Brandt 2008)
The damage evolution law and damage mechanism at a material level are the key aspects for accurate prediction of the mechanical behavior of PFRC structures
A good understanding of the monotonic/cyclic stress–strain behavior and damage mechanism of PFRC is of great importance for the engineering design of PFRC structures and the application of PFRC material

Summary

Introduction

Polypropylene fiber reinforced concrete (PFRC) has been experiencing a rapid development and its application has become widespread in civil engineering fields, such as constructions, bridges, surface of pavements, tunnel linings and hydraulic structures (Brandt 2008). It is acknowledged that the reliable design and seismic retrofit of PFRC structures against external complex actions, e.g., earthquake, fatigue and other types of loads, necessitates a clear comprehension of the Journal information: ISSN 1976-0485 / eISSN 2234-1315 mechanical behavior of PFRC under both monotonic and cyclic loadings. As demonstrated by experimental observations (Li and Ren 2009; Dassios et al 2013), the failure behaviors of concrete members and structures are mainly determined by the damage accumulation during the loading process. The damage evolution law and damage mechanism at a material level are the key aspects for accurate prediction of the mechanical behavior of PFRC structures. A good understanding of the monotonic/cyclic stress–strain behavior and damage mechanism of PFRC is of great importance for the engineering design of PFRC structures and the application of PFRC material. As reported by previous studies (Song et al 2005; Xu et al Int J Concr Struct Mater (2018) 12:68

Objectives

Methods

Results

Conclusion