(1) Department of the Natural and Built Environment, Sheffield Hallam University,

Sheffield, South Yorkshire, S1 1WB, England



This project was designed to compare and contrast the performance characteristics and properties of a variety of different mortar mixes, with the entire sample set being tested at 28 days. Volume proportioned mortar mixes were produced using both eminently hydraulic lime (NHL5) and Portland cement to give target performance strength specifications of M2, M4 and M6. These target strength specifications are equivalent to traditional volume proportions of 1:3, 1:6 and 1:8.

   In each case the mortars were made using a constant mass of sand and the correct proportions of each mortar mix were obtained by varying the mass of binder used. This was designed to give greater control over the water content of each mix.

   Bond strength tests were performed on couplets using a direct tensile test, developed at Sheffield Hallam University. The results indicated that Portland cement mortars consistently performed better than the corresponding hydraulic lime mortars in terms of tensile bond strength. However, the results also indicated that the higher mix proportion limes did compare favourably with the lower proportioned cement based mortars.


KEYWORDS: masonry, tensile bond strength, eminently hydraulic lime (NHL5), Portland cement mortar, comparative studies.