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Indexed by:期刊论文

Date of Publication:2016-12-15

Journal:CONSTRUCTION AND BUILDING MATERIALS

Included Journals:SCIE、EI、Scopus

Volume:128

Page Number:154-162

ISSN No.:0950-0618

Key Words:Concrete-filled steel tube; Void area; Ultrasonic testing method; Propagation path; Chromatogram; De-bonding

Abstract:Due to shrinkage and/or inadequate compaction during concreting, voids may develop in a concrete-filled steel tube (CFST) between the concrete core and outer steel tube, which reduce the confinement effect of the steel tube on the concrete core, and further, decrease the load-carrying capacity and ductility of a CFST. In this study, an ultrasonic technique is utilized for quantifying voids in CFSTs by analyzing the ultrasound travel time in them. Four potential travel paths are identified in CFSTs with/without preset voids. By making a comparison of the experimental and theoretical ultrasound travel time, the actual ultrasound travel path is determined in CFSTs. Further, by analyzing the matrix of ultrasound travel time obtained from experiment, a novel method is proposed to generate the chromatogram of the distribution of ultrasound travel time, which is utilized to quantify the voids in a CFST. The chromatogram intuitively shows the position and geometry of the voids in CFST5 and is in reasonable agreement With the pre-set voids. This study, therefore, establishes a new method for quantifying voids in a CFST through the ultrasonic technique. (C) 2016 Elsevier Ltd. All rights reserved.