|
Abstract: Successive coating a lay of postponed-set mortar (PSM) on prestressed strand is a key to engineering application for a new type of bond-retarded prestressed concrete system. According to the principle of screw conveying and die forming, coating equipment for bond-retarded prestressed strand is developed and coating experiments are carried out. Based on the theories of rheology, successive coating process of PSM is analyzed. The theoretical analysis and the experimental results show the followings. In order to achieve automatically and successively coating PSM and plastic (sealing PSM) on prestressed strand only once, both PSM with Bingham plastic in screw channel and annular passage surrounding strand and polyethylene sheath must be in fully flow state, which means screw revolutions and coating velocity exist respective critical values.
Key words: Prestressed concrete strand Postponed-set mortar Successive coating
CLC No:
TU646 TU311
铁道部科技发展计划(96G56)和甘肃省科技攻关计划(GS003-A52-019)资助项目.
Received
20070228,
received
in
revised
form
20070802
|