Bond characteristics of fibre reinforced mortar in masonry using image analysis

The flexural bond strength between brick and mortar is a measure of the ability of masonry to resist applied stress and differential movements. It can be considered as the stress required to cause failure and is quantified by the masonry flexural strength. The paper is the further development of previous study on the influence of steel and polypropylene short fibres on masonry flexural bond strength characteristics with a view to improving the strength of masonry constructions. The addition of fibres in concrete materials improves concrete tensile strength in many applications; however, little has been done to transfer this approach to mortar in masonry applications. Research by the investigators using quantitative image analysis has found some potential benefits from the addition of the fibres, particularly in relation to the relationship between the flexural bond strength and microstructure characteristics of the mortar and the resulting shear bond strength. Image analysis, as an evolving technique in engineering applications to observe microstructure of objects and extract relevant information from samples, was applied to analyse the interface between brick and mortar to quantify various microstructure features. It was found that the samples with steel fibres exhibited lower flexural bond strength when greater porosity and larger pores were observed.