Rationale

Because of the higher strength of modern cements, mortars are much stronger than historically. Type K was removed in 1982 as it was largely unnecessary except in very specific instances. The formula for a proportioned Type K was maintained in the appendix. However, with the higher strength of Type N and Type O mortars today, C15 would like to investigate the possibility of reinstating Type K as a low strength alternative when using salvaged brick or working with historical masonry where Type O may be too strong. With the appendix to C270 pending a significant overhaul, now is a good time to discuss resurrecting Type K.