Experimental Study of Bond Behavior Between Rebar and PVA-Engineered Cementitious Composite (ECC) Using Pull-Out Tests

Jie Xiao,Haibo Jiang,Lingfei Liu,Keyi Zhai,Xiang Long,Ming Ye

doi:10.3389/fmats.2021.633404

Jie Xiao, Haibo Jiang + Show 4 more

Open Access

https://doi.org/10.3389/fmats.2021.633404

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Abstract

As a novel civil engineering material, Engineered Cementitious Composite (ECC) has attracted more and more attention due to its strain-hardening characteristics, good post-cracking resistance and its unique properties. Bonding between Engineered Cementitious Composite (ECC) and rebar has a great effect on the mechanical behavior of structural members. In this paper, direct pull-out tests were conducted to understand the bond behavior between the ECC and rebar. The test parameters included rebar diameter and type, cover layer thickness, embedment length and fiber volume content. Bond-slip curves, failure and cracking pattern and bond strength were compared and discussed. The test results indicated that the bond strength decreased with the increase of embedded length. Through regression analysis with the test data, the functional relationships between bond strength and cover layer thickness and rebar diameter were fitted well. According to the positive and negative signs of the fitting parameters m and n, the relationship between the bond strength and the cover layer thickness and the rebar diameter could be determined. The bond strength increased obviously with the increase of fiber content. When the fiber volume content was 1, 1.5 and 2%, the bond strength of these specimens were 1.5, 2.5 and 3.1 times that of specimens without polyvinyl alcohol (PVA) fiber.

Highlights

Concrete is one of the most widely used and studied building materials in civil engineering projects around the world (Jiang et al, 2016; Xiao et al, 2016; Zhang et al, 2018; Wang et al, 2020a; Wang et al, 2020b; Wang et al, 2020c; Yu et al, 2020a; Wang et al, 2021; Xiong et al, 2021)
When the diameter of the rebar changed under the same embedment length, the experimental bond strength would be larger if the embedment length was less than 5 times the diameter of the rebar
This paper investigated the bond behavior of rebar embedded in engineered cementitious composite (PVA-ECC) by pull-out test and evaluated the influence of rebar diameter and type, cover layer thickness, embedment length and fiber volume content

Summary

INTRODUCTION

Concrete is one of the most widely used and studied building materials in civil engineering projects around the world (Jiang et al, 2016; Xiao et al, 2016; Zhang et al, 2018; Wang et al, 2020a; Wang et al, 2020b; Wang et al, 2020c; Yu et al, 2020a; Wang et al, 2021; Xiong et al, 2021). Investigated the bond behavior of steel bar embedded in ECC by pull-out test to consider the influence of bar shape, bar diameter, ECC strength, cover thickness and fiber volume content and concluded that the bond stress-slip curves of ECC specimens declined slowly which demonstrated better ductility than that in reinforced concrete (Chao et al, 2009). Pull-out tests were used to study the bond behavior of steel bar-ECC considering the effects of parameters such as steel bar diameter and type, cover layer thickness, embedment length and fiber volume content. Specimen E-B16R denoted pull-out test specimen with engineered cementitious composite (ECC), embedment length of [80, 16] mm-diameter plain rebar and PVA fiber fraction of 2%. Specimen E-B16–1.5 denoted pull-out test specimen with engineered cementitious composite (ECC), embedment length of [80, 16] mm-diameter deformed rebar and PVA fiber fraction of 1.5%. The average relative slip between the rebar and the matrix along the anchorage section can be calculated as follows:

EXPERIMENTAL RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT