Graham. R. Sargeant1
1)  H+H UK Ltd,
Celcon House, Ightham, Sevenoaks, Kent TN15 9HZ United Kingdom

Keywords: Bond, Wrench, AAC, Mortar, Ice, Temperature.

Abstract. Investigation into bond strength development between Autoclaved Aerated Concrete (AAC) and various mortars determined using bond-wrench apparatus designed using the principles of prEN 1052-5:2002 (E). The main thrust of the work was the comparison between traditional mortars and thin layer mortars and how the relative bond strengths were developed at ambient and sub-zero temperatures.
The work showed that unlike traditional mortars, certain thin layer mortars were suitable for use around zero degrees. It also highlighted the importance of introducing a thawing period during the test regime as results could be skewed by the significant influence of ice-bonds if testing was carried out immediately after removal from the sub-zero environment.
In the UK, traditional mortar predominates and cannot be used at temperatures of 3°C and falling. As a consequence of this work, AAC masonry can now be built in the UK at 0°C, this helping to increase masonry site productivity.