Abstract This report presents results of a preliminary investigation dealing with the compressive strength development of alkali activated ground granulated blast-furnace slag concretes. These concretes incorporated sodium silicate as an activator but did not contain any portland cement. The five concrete mixtures studied were proportioned using sodium silicate and small amounts of hydrated lime. The water-to-binder ratio of the mixtures ranged from 0.34 to 0.50. The air-entrained concrete produced satisfactory workability. The 1-day and 28-day compressive strengths of the concretes ranged from 20.4 to 38.9 MPa and from 45.5 to 59.6 MPa, respectively. 2he 7- and 14-day flexural strengths were of the order of 5 MPa.