Slant shear test

ABSTRACT This research project aims to use reactive powder concrete, RPC. as a new repair material and evaluate its bond strength and bond durability to existing concrete. One accelerated aging environment, namely a freeze-thaw cycle acceleration deterioration test, was selected for the evaluation of bond durability of the repair materials. Before and after aging, the samples were evaluated by the compressive strength, bond strength (slant shear test), steel pull out strength, and relative dynamic modulus NDT tests. 

Tests performed in this experimental study included abrasion resistance, compressive strength, twnd strength (slant shear test), steel pull out strength, and relative dynamic modulus NDT tests. 

There were three different failure modes in this slant shear test. The failure type for RC/RC specimens was interface failure. The failure modes for RPC/RPC specimens included repair material failure and substratum failure. The failure modes for HSM/RC and RPC/RC specimens were interface failure or substratum failure. RC and HSM specimens have relatively lower concrete bond strength, while RPC specimens still have relatively higher values after 1000 freeze-thaw cycles. 

The results of slant shear tests show that the bond strength of RC/RC, HSM/RC. and RPC/RC decreased significantly more with ffeeze-thaw cycling as compared with thatofRPC/RPC. 

Little information exists on the effects of surface pretreatment on bond strength and durability, and there is a general absence of appropriate test methods to assess such effects on adhesion. The pull-off test(68) is, perhaps, currently the most suitable the slant-shear test, as described in BS 6319(69), is of limited use in assessing adhesion because the interfaces are not subjected to tensile forces. 

With SBR slurries the use of more than one coat can reduce bond strengths assessed using the slant shear test(13). It is now accepted that these materials form a skin if allowed to dry which can impair adhesion of subsequent layers. 

Slant shear test, loaded in compression, for resins used in construction concrete substrates used Collar and pin bonded with anaerobic adhesive and loaded in tension... 

Three adhesive formulations were chosen to cover the anticipated temperature range at the time of application, i.e. 4 C-38 °C. Control of correct mixing and materials was achieved by measuring hardness of small specimens after curing for 20 minutes in a small oven. Subsequently slant shear and compressive strength tests were performed. 

BS 6319 Part 4 1984. Testing of resin compositions for use in construction. Part 4, Method for measurement of bond strength (slant shear method), British Standards Institution, London. 

The tests reported by Julio etaL (2004) on slant shear and pull-off specimens... 

Figure 4.50i l indicates the adhesion of latex-modified mortars to ordinary cement mortar as a substrate, measured by four types of test methods. CJenerally, the adhesions in tension, flexure, and direct compressive shear of the latex-modified mortars to ordinary cement mortar increase with a rise in the polymer-cement ratio regardless of the type of polymer and test method. The adhesion in slant (indirect) compressive shear of the latex-modified mortars attains a maximum at a polymer-cement ratio of 5 or 10%, and is extremely large compared to the adhesions determined by other test methods irrespective of the polymer type and polymer-cement ratio. The reasons for diis may be due to the effects of the combined shear and compressive stresses and their relaxation by the polymer films formed on the bonding joints. Considering the above adhesion data, it is most important to select the best test methods to successfully reproduce service conditions in the applications of the latex-modifled mortars. 

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