Ten aluminosilicate waste materials (fly ashes and mineral wastes) were studied for their chem., phys. and mineral. properties, leached with 1% HF soln. at room temp., calcinated at 1000 degrees C, alkali-activated (cured) in 12 M NaOH soln. and studied for flexural and compressive strengths. All aluminosilicate materials were converted to useful building materials. The high contents of aluminosilicate and vitreous phase resulted in an improvement of the product properties. The high contents of SO3 and Ca as well as high ignition losses contributed to deterioration of the product quality.