Selective demolition of masonry unit walls with a soundless chemical demolition agent.

• SCDA insertion into unit masonry walls of new and historic bricks and mortar. • Type N mortar exhibited slower but significantly more and wider cracking than lime only mortar. • Partial demolition, though not selective unit removal, was achieved for the first time in masonry walls. • Demonstrated viability of SCDAs for partial demolition of full-scale unit masonry. A soundless chemical demolition agent was applied for selective demolition to unit masonry [2 full-scale concrete brick walls in Type N mortar and 2 wallettes in lime mortar – 1 historic brick and 1 concrete brick]. Typically, cracking began shortly after 9 h and ultimately produced an average crack length of 418 mm per hole and an average maximum 5.22 mm crack width. Samples in Type-N mortar exhibited slower but significantly more cracks and wider cracking. Ninety-three percent of cracking occurred within 4 days. No masonry units were damaged and partial demolition was successful, although selective unit removal was not due to confinement. [ABSTRACT FROM AUTHOR]