An effective way to reduce the impact of cement production on the environment is to use supplementary cementitious materials (SCM) as a partial substitution to cement. In addition to the reduction in cost and energy saving, the use of SCM in cement for the manufacture of mortar and concrete offers technical advantages. In this paper, cement was partially substituted by fines obtained from crushed recycled bricks recovered from a brick plant. The level of substitution was either 0%, 5%, 10% or 15% by weight of cement. The results show that cement substitution by brick fines resulted in a slight loss of workability with the increase of the substitution rate. Substitutions rates of 5% and 10% produced at long-term comparable strength as control mortars. The differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) results show cement hydration improved significantly with different rates of substitutions at 28 and 180 days of age.