Testing of Bond Between Fresh and Hardened Concrete

Abstract

The bond between fresh and hardened concrete can be subjected to various stress states depending on the application and service conditions. Four test methods, reflecting different stress states at the bond between the fresh and hardened concrete, are evaluated. The four methods are a slant shear test, an indirect tension test and two different flexure tests.The slant shear test is shown to b~ consistent and the most sensitive test in showing the strength of the bond, and was used to evaluate the effect of the following parameters on that strength:We conclude that copolymer PVA is a poor bonding agent over a wide range of curing conditions and that the thickness of a portland cement mortar layer has a strong influence on bond strength. The other factors did not affect strength significantly.

The Longitudinal Shear Behavior of Carbon Fiber Grid Reinforced Concrete Toppings

“…According to Hindo (1990) Other testing methods exist such as those discussed by Wall et al (1986) Conclusions or recommendations in this report are the opinions of the authors. PCI assumes no responsibility for the interpretation or application of the information contained herein.…”

Suitability of different tests for characterization of the dimpled concrete‐to‐concrete interface

“…Abu-Tair et al 11 developed a modified setup suitable for characterizing the tensile bond strength of thin repair layers (20-25 mm) or repair material placed between two halves of a substrate concrete specimen. Wall et al 12 performed flexure tests, with bond planes at 45 and 60 relative to the horizontal axis, in accordance with ASTM. 16 .…”

“…proposed by: (a) Ohama et al, 10 (b) Abu-Tair et al, 11 (c) Wall et al, 12 (d) Kunieda et al, 13 and (e) Kamada and Li 14 F I G U R E 3 (a) Direct tension test, (b) pull-off test, and (c) twist-off test effects of drilling depth, shrinkage, and material mismatch, by means of numerical analysis and an extensive experimental program.…”

Bond strength evaluation of polymer modified cement mortar incorporated with polypropylene fibers

“…There are several tests available to evaluate the behavior and/or the strength of overlay-to-substrate interfaces. These tests can be classi ed into three categories according to the stress resultant at the interface 1) axial, includes; Pull-off (Long and Murray, 1984;Delatte et al, 2000), Direct Tension (Ohama et al, 1986), and Split-Tensile test (Sustersic and Zajc, 1999;Tschegg et al, 2000), 2) bending, includes exural test (Wall et al, 1986;Abu-Tair et al, 1996;Kunieda et al, 2000;Kamada and Li, 2000), and 3) shear, includes testing by; Direct Shear (Chen et al, 1995;Li et al, 1997), Slant-Shear (Tayeh et al, 2013;Pattnaik, 2015), Bi-surface shear, and Push-off (Hofbeck et al, 1969;Mattock, 1974;Crane, 2010).…”