This specification covers requirements for chemically setting silicate and silica chemical-resistant mortars for bonding chemical-resistant masonry units. The setting agent generally used is an acid compound that reacts with the silicate binders, or an alkaline compound that reacts with the silica sol binder, to form an insoluble silica gel. The filler materials shall be selected to have resistance to the particular chemicals to which they will be exposed. Chemically setting silicate or silica chemical-resistant mortars prepared from these materials shall conform to the respective physical requirements prescribed. The liquid binder shall be of a viscosity that will permit it to be readily mixed manually with the filler. The bond strength, absorption, working life and setting times, shrinkage, compressive strength, and flexural strength shall be tested.