ABSTRACT
This paper giv e s i n f o r m a t i o n of four d i f f e r e n t ways to i n f l u e n c e on the w o r k a b i l i t y time of high s t r e n g t h conc r e t e s . Besides concise phenomenological review the s e l e c t i o n of compatible s u p e r p l a s t i c i z e r binder combinat i o n and simultaneous use of s u p e r p l a s t i c i z e r and r e t a r d - er are discussed s h o r t l y * Delayed dosage of the superp l a s t i c i z e r i n t o the mixer and repeated dosage of the s u p e r p l a s t i c i z e r are the main fe a t u r e s examined i n the paper. Using delayed s u p e r p l a s t i c i z e r dosage or both delayed s u p e r p l a s t i c i z e r dosage and repeated superplast i c i z e r dosage at the b u i l d i n g s i t e , over 80-90 minutes w o r k a b i l i t y times were achieved w i t h s e v e r a l superplast i c i z e r binder combinations.
