ABSTRACT

In 1974 , "Th e Researc h Committe e o n Disposa l an d Reus e o f Construction waste " wa s establishe d b y Buildin g Contrac - tors Society(BCS ) i n Japan . Abou t 7 year s later , th e similar projec t tea m wa s starte d b y Ministr y o f Construc - tion t o confir m th e result s o f BC S an d propose d fou r Guid - lines o n th e recycle d aggregat e an d recycle d aggregat e concrete fo r th e Public k wor k an d Buildin g respectively . In 1988 , Th e 2n d Internationa l Symposiu m o n Demolitio n an d Reuse o f Concret e an d Masonr y hele d i n Tokyo . Th e author s

r e p o r t e d t h e t e s t r e s u l t s o f a b o u t 2 0 s a m p l e s o f r e c y c l e d c o a r s e a g g r e g a t e f r o m t w o d i f f e r e n t p r o c e s s i n g p l a n t s i n t h e s u b u r b s o f T o k y o . I n t h e p a p e r , t h e a m o u n t o f i m p u r i t i e s an d f i n e p a r t i c l e s i n r e c y c l e d c o a r s e a g g r e g a t e w e r e i n v e s t i g a t e d . B u t w e d i d n ' t mak e i t c l e a r t h e r e l a t i o n s h i p b e t w e e n t h e i m p u r i t i e s o f r e c y c l e d a g g r e g a t e a n d t h e s e v e r a l p r o p e r t i e s o f r e c y c l e d a g g r e g a t e c o n c r e t e . I n t h i s p a p e r , t h e e f f e c t s o f s o r t an d c o n t e n t s o f i m p u r i t i e s i n r e c y c l e d c o a r s e a g g r e g a t e o n t h e p r o p e r t i e s o f r e c y c l e d c o n c r e t e w e r e t e s t e d .