Evaluation of Bond Strength in Concrete Elements Externally Reinforced with CFRP Sheets and Anchoring Devices

This paper presents an experimental investigation of the bond strength between carbon fiber reinforced polymer (CFRP) and steel substrate by utilizing the pull-off test and scanning electron microscope (SEM) analysis. A series of pull-off experiments was conducted by using three types of CFRP (CFRP sheets and CFRP laminates with/without woven mesh) and two types of epoxy adhesive (ductile and brittle epoxy adhesive) with/without carbon nanotube (CNT) modification. Pull-off samples with CFRP laminates possess higher (about double) bond strength than that of samples with CFRP sheets, due to the good saturation of fibers in the laminates. The steel-CFRP bond with ductile epoxy adhesive (Araldite 2011) is found to have about 16% higher bond strength when compared to that of brittle epoxy (MBrace Saturant), even though the tensile strength of Araldite 2011 is about 40% less than that of MBrace Saturant. Also, it is shown that modified epoxy with CNTs is more efficient than neat epoxy for bonding CFRP to steel at a moderately elevated temperature, and increasing the bond strength about twofold.

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Double shear tests to evaluate the bond strength between GFRP/concrete elements

Composite Structures ◽

10.1016/j.compstruct.2011.09.003 ◽

2012 ◽

Vol 94 (2) ◽

pp. 681-694 ◽

Cited By ~ 26

Author(s):

Hugo C. Biscaia ◽

Carlos Chastre ◽

Manuel A.G. Silva

Keyword(s):

Bond Strength ◽

Shear Tests ◽

Double Shear ◽

Concrete Elements

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Evaluation of bond between reinforcement and concrete

MATEC Web of Conferences ◽

10.1051/matecconf/201823002027 ◽

2018 ◽

Vol 230 ◽

pp. 02027 ◽

Cited By ~ 3

Author(s):

Olena Romashko ◽

Vasyl Romashko

Keyword(s):

Bond Strength ◽

Stressed State ◽

Statistical Evaluation ◽

Contact Layer ◽

Normal Stresses ◽

Tangential Stresses ◽

Universal Dependence ◽

State Changes ◽

Experimental Values ◽

Concrete Elements

The scheme of stressed state changes of the concrete contact layer and reinforcing rod during its pulling out of concrete is considered. The most important drawbacks of the known methods for evaluating the bond strength of reinforcement to concrete have been analyzed. Particular attention is focused on bond estimating by average tangential stresses. It is substantiated why the linear dependence of these stresses on normal stresses in the reinforcement cannot cover the processes of reinforcement bonding with concrete in the stage of use of reinforced concrete elements. A universal dependence of the average tangential stresses for estimating the reinforcement bond to concrete at any stage of elements deformation is proposed. Statistical evaluation of the obtained dependence was made on the basis of theoretical and experimental values of the average tangential bonding stresses comparison. The area of use of reinforcement bond with concrete average stresses dependence is defined.

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