Shear accelerated ageing

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. 

Figure 7.9 Toughness (Gunl onset of non-linear response and G,io mode II delamination) plotted against log (immersion time). (Reproduced from Influence of water and accelerated aging on the shear fracture properties of glass epoxy composite, page 84 in Applied Composite Materials 1996 3 (2) with the kind permission of Peter Davies and Kluwer Academic Publishers.)...

P Davies, F Pomies and L A Carlsson, Inllnence of water and accelerated aging on the shear fracture properties of glass/epoxy composite , Appl Compos Mater... 

Accelerated ageing G W CRITCHLOW Shear and wedge tests, humidity, corrosive environments... 

D-2559. Specification for Adhesives for Structural Laminated Wood Products for Use Under Exterior (Wet Use) Exposure Conditions. Sample beams, made under various assembly time extremes, are tested for (a) basic dry glueline shear strength and wood failure and (b) resistance of glueline to delamination after accelerated aging. It also requires testing the adhesive s diy creep resistance. Used in qualifying new adhesives for use in exterior laminated beams. 

Adhesives for ceramic tiles are specified by the standard EN 12004 2007 (Adhesives for tiles. Requirements, evaluation of conformity, classification, and designation), and includes performance requirements for cementitious, dispersion, and reaction resin adhesive types for all internal and/or external wall, floor and ceiling applications. Annex ZA, of this standard, sets out the requirements, which address the provisions of the Construction Products Directive (see O Sect. 35.4 below), and include assessments of durability. Compliance with these requirements confers a presumption of fitness for purpose for the applications and form part of a CE mark. In these cases durability is assessed by elevated temperature and/or water immersion accelerated ageing or freeze-thaw cycling of test specimens and then determining tensile or shear adhesion strength against minimum requirements. 

Tear strength is only applicable to flexible materials and is very little used to monitor ageing simply because tensile strength will serve perfectly well. There are circumstances where compression stress-strain properties would be relevant but the relatively bulky test pieces will be subject to the limitation of oxygen diffusion in any accelerated tests and changes can probably be estimated from tensile measurements. Similarly, shear stress-strain is very rarely used for monitoring ageing. 

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