1) Professor, University of Bath, BRE Centre for Innovative Construction Materials, p.walker@bath.ac.uk

2 PhD student, University of Bath, BRE Centre for Innovative Construction Materials, ab0smk@bath.ac.uk

3) MEng student, University of Bath, Dept. Architecture & Civil Engineering, ahj24@bath.ac.uk


The paper presents the results from an experimental study comparing the use of CL90-S grade hydrated lime with a proprietary air-entraining agent for the production of cement:lime:sand and cement:sand:admixture mortar mixes varying between M2.5 and M10. The study compared fresh (flow table) and hardened (28-day flexural compressive) mortar properties, masonry bond wrench flexural strength and the yield (number of bricks laid for given mortar quantity). Two different mortar sand gradings (fine and medium) were used in the comparison. The cement:lime:sand mortars showed good compliance with expected performance criteria. Air-entrained cement based mortars underperformed in respect of target compressive strength and adhesion values. The high air-entrainment to obtain the target workability increased the yield for the admixture mortars, which was marginally higher than for the lime mortars. Mortar compressive strength improved using the coarser graded sand.


Keywords: Hydrated lime, masonry mortar, air-entraining admixture