Bond properties for plain bars in frost-damaged concrete

Typical applications for post-installed rebar connections consist in overlapping joints with existing reinforcement or anchoring of the reinforcement at a slab or beam support. At cold state it may be shown by testing that a post-installed rebar system can develop the same bond resistance with the same safety margin as cast-in-place rebar. Consequently, anchorage length and lap length for post-installed rebars can be calculated as for cast-in-place according to the Eurocode 2 provisions. However, when subjected to temperature, the decay in bond properties for post-installed systems is significantly more dramatic than for cast-in-place rebars. The paper presents the result of an experimental campaign carried out on a post-installed connection using a vinylester polymer, investigating the effects on the bond strength both of the temperature and of different testing conditions. Finally, design criteria are provided and applied to a typical case study consisting in a post-installed solid slab.

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F–H···N hydrogen bonds: Influence of substituent and hybridization of nitrogen on H-bond properties and two-bond 19F–15N spin–spin coupling constants (2hJF–N)

Chemical Physics Letters ◽

10.1016/j.cplett.2010.03.051 ◽

2010 ◽

Vol 491 (1-3) ◽

pp. 11-16 ◽

Cited By ~ 3

Author(s):

Ali Ebrahimi ◽

Mostafa Habibi-Khorassani ◽

Masoome Doosti

Keyword(s):

Hydrogen Bonds ◽

Coupling Constants ◽

Spin Coupling ◽

Bond Properties ◽

Spin Coupling Constants ◽

Spin Spin Coupling

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Fiber Debonding Along a Crack Front in Paper

MRS Proceedings ◽

10.1557/proc-539-153 ◽

1998 ◽

Vol 539 ◽

Cited By ~ 1

Author(s):

H. Kettunen ◽

K. J. Niskanen

Keyword(s):

Fracture Energy ◽

Crack Front ◽

Fracture Process ◽

Fracture Process Zone ◽

Process Zone ◽

Bond Properties ◽

Crack Line ◽

Pull Out ◽

Microscopic Damage ◽

Debonding Process

AbstractWe follow the accumulation of microscopic damage ahead the crack tip in paper. The fiber debonding process varies even within each specimen because of large variation in fiber and bond properties. In general, stiff and weakly bonded fibers tend to debond as a rigid body while ductile or well bonded fibers pull out gradually in a process that propagates from the crack line to the fiber ends. Particularly in the latter case the network ruptures coherently rather than through debonding of single fibers. Experimental analysis and simulations show that fracture energy correlates closely with the size of the fracture process zone (FPZ) irrespective the nature of the debonding process. Only the cases of low bonding and stiff fibers seem to make an exception in that FPZ can grow in size without a corresponding increase in fracture energy.

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Bond paths and bond properties of carbon-lithium bonds

Journal of the American Chemical Society ◽

10.1021/ja00254a004 ◽

1987 ◽

Vol 109 (20) ◽

pp. 5909-5916 ◽

Cited By ~ 75

Author(s):

James P. Ritchie ◽

Steven M. Bachrach

Keyword(s):

Bond Properties

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