ABSTRACT
In s p i t e of these discouraging r e s u l t s a commercial i n s t a l l a t i o n was a c t u a l l y e s t a b l i s h e d i n Dusseldorf f o r the production of masonry u n i t s made with ground b r i c k powder and lime by steam curi n g ( 7 1 ) . T e s t s had shown that the r e c y c l e d r u i n s - d e r i v e d rubble contained s u f f i c i e n t r e a c t i v e s i l i c a which strengthened the p a r t i c l e s t r u c t u r e by forming calcium s i l i c a t e hydrate i n the course of the autoclave treatment, a f t e r mixing i n of an appropriate quantity of calcium hydroxide. The compressive s t r e n g t h of the blocks produced was around 13 N/mm^ ; they were c l a s s i f i e d as Mz 10. Improvements i n compressive s t r e n g t h were p o s s i b l e by mixing i n appropriate amounts of lime and by i n c r e a s i n g the cur i n g time. Water absorption of the blocks was 17%. By using almost pure crushed b r i c k , the p r o p e r t i e s of the blocks i s s a i d to have come very c l o s e to the p r o p e r t i e s of baked c l a y b r i c k s ( 7 1 ) .
