Pozzolan cements are produced by adding pozzolans such as silica fume, rice husk ash, blast furnace slag, fly ash, trass in 20% replacement for Portland cement. On the 28th day of production, the produced specimens are stored in water, in MgSO4 . 7H(2)O (5%) solution and in HCl (pH = 2) solution. The strengths and weights were determined after the mortars are stored in solutions for 56 days. Compressive strengths of the mortars stored in water for 28 days are silica fume, rice husk ash, and control, 43.3, 40.1, and 31.0 MPa, respectively. The highest loss of compressive strength is 20% and the highest gain of weight is 4.2%, occurring in blast furnace slag mortar in MgSO4. (C) 1997 Elsevier Science Ltd.