Feasibility of Reduced Lap-Spliced Length in Polyethylene Fiber-Reinforced Strain-Hardening Cementitious Composite

Seok-Joon Jang,Wonchang Choi,Hyun-Do Yun

doi:10.1155/2018/1967936

Abstract

This research investigates the interfacial behavior between polyethylene (PE) fiber-reinforced strain-hardening cement composite (PE-SHCC) and reinforcing bars that are spliced in the tension region to determine feasibility of reduced lap-spliced length in PE-SHCC. Twenty test specimens were subjected to monotonic and cyclic tension loads. The variables include the replacement levels of an expansive admixture (0% and 10%), the compressive strength of the SHCC mixtures (40 MPa and 80 MPa), and the lap-spliced length in the tension region (40% and 60% of the splice length recommended by ACI 318). The PE-SHCC mixture contains polyethylene fiber to enhance the tensile strength, control the widths of the cracks, and increase the bond strength of the lap splice reinforcement and the calcium sulfo-aluminate- (CSA-) based expansive admixture to improve the tension-related performance in the lap splice zone. The results have led to the conclusion that SHCC mixtures can be used effectively to reduce the development length of lap splice reinforcement up to 60% of the splice length that is recommended by ACI 318. The addition of the calcium sulfo-aluminate-based expansive admixture in the SHCC mixtures improved the initial performance and mitigated the cracking behavior in the lap splice region.

Highlights

Many research studies have been carried out to investigate the force transfer from the reinforcement to the concrete in a splice zone in both tension and compression [1,2,3,4,5,6,7]
Ganesan et al [6] reported that the confinement and bridging effect of hybrid fibers enhanced the bond strength of deformed reinforcing bars embedded in hybrid fiber-reinforced high-performance concrete (HFRHPC) composites when compared to plain high-performance concrete (HPC). ey concluded from their test results that the anchorage length requirement for deformed bars can be reduced by the usage of HFRHPC
Twenty strain-hardening cement composite (SHCC) specimens were fabricated to examine the tensile performance in the lap splice zones; the tensile performance was based on the mechanical characteristics of the reinforcing bers and mixing conditions. e splice lengths for the concrete specimens (C40 and C80) were computed using the equation found in ACI 318

Summary

Introduction

Many research studies have been carried out to investigate the force transfer from the reinforcement to the concrete in a splice zone in both tension and compression [1,2,3,4,5,6,7]. Several investigations have been carried out to study the e ect of ber as an alternative method for improving the bond strength between concrete and reinforcement. E pullout loads of the deformed steel reinforcement are a ected by the mechanical properties of the concrete mix, concrete cover, amount of steel bers, and the aspect ratio of the steel bers. SHCCs reinforced with ber show superior tensile performance, which includes the control of crack propagation, but considerable shrinkage was observed due to the rich mix design [14]. Is study investigated the e ects of the expansive admixture, compressive strength, and the reduced lap splicing length associated with the bond performance in the splice region. It is likely that the initial shrinkage cracks adversely a ect the tensile strength, lap splice length, and bond behavior in the splice region. To compensate for the excessive shrinkage of the SHCC mixtures, the cement was replaced with an expansive admixture [15]

Experimental Program

Experimental Results

Conclusions