Development of a novel binder for mortar for unfired clay bricks

Interest in traditional unfired clay building materials has grown in the UK in recent years. Although the use of vernacular techniques has raised the profile of earthen architecture, a wider impact on modern construction is more likely to come from modern innovations such as unfired extruded clay masonry units. Traditional unfired clay walls often have basal widths of 300mm or more, providing an inherent stability through self-weight. Masonry units extracted from UK brick production lines before the firing process are typically 100mm wide, which requires good mortar-brick bond strength to meet structural robustness requirements in a typical 2.4m high wall. In testing, traditional mortars have not provided sufficient strength. This paper reports on the development of a mortar which appears to be suitable for a wide range of clay types. Results of long term tests demonstrate the suitability of this mortar for use with unfired clay masonry units.