ABSTRACT
This paper deals w i t h a study, the purpose of which was t o study some of the f a c t o r s a f f e c t i n g the w o r k a b i l i t y of concrete. A new apparatus c a l l e d I n t e n s i v e Compaction Tester has made t e s t s p o s s i b l e f o r no-slump concrete and 2-Point Tester f o r semi-and high-slump concretes. Even small changes i n w o r k a b i l i t y can be observed by the methods. I n v e s t i g a t i o n s show t h a t the w o r k a b i l i t y i s improved by, s u p e r p l a s t i c i z e r , s i l i c a fume and high-grade sand. The w o r k a b i l i t y i s d e t e r i o r a t e d by sand w i t h a high s i l t content. Keywords : No-slump concrete, High-slump concrete, Workab i l i t y , T e s t i n g , S i l i c a fume, Aggregate, Hollow-core s l a b , S u p e r p l a s t i c i z e r
1 Introduction
The measuring of the b a s i c r h e o l o g i c a l p r o p e r t i e s of semi-and high-slump concretes i s not p o s s i b l e w i t h the usual w o r k a b i l i t y t e s t s l i k e w i t h the slump t e s t . P a r t i - c u l a r l y when producing s p e c i a l concretes l i k e high stre n g t h grades, i t i s important t o know such f a c t o r s as y i e l d value and p l a s t i c v i s c o s i t y . Otherwise the c o n t r o l of p r o p e r t i e s of f r e s h concrete i s u n r e l i a b l e . The e x c e l l e n t p r o p e r t i e s of no-slump concrete have o f t e n been recognized, but the l a c k of appropriate t e s t and compaction methods i n p a r t i c u l a r has l i m i t e d both i t s use and i n v e s t i g a t i o n . No-slump concretes are a l s o s e n s i t i v e t o l o c a l c o n d i t i o n s , f o r which reason the r e s u l t s obt a i n e d i n d i f f e r e n t places are d i f f i c u l t t o compare with one another. The two p o i n t t e s t e r f o r semi-and high-slump concretes has been used i n t h i s study. The apparatus i s developed by Dr. G.H. T a t t e r s a l l and the p r i n c i p l e s and a p p l i - c a t i o n s are w e l l known. The apparatus used i n t e s t s was a l s o equipped with a conversion k i t f o r semi-workable concretes. A new t e s t method i n c l u d i n g an equipment c a l l e d I n t e n s i v e Compaction Tester (ICT) has been used f o r t e s t i n g no-
slump concrete f o r hollow-core s l a b s . The t e s t e r i s designed p a r t i c u l a r l y f o r t e s t i n g the p r o p e r t i e s of noslump concrete. The t e s t e r can be used f o r monitoring w o r k a b i l i t y and f o r the manufacture of c y l i n d r i c a l sampl e s t o t e s t the compressive strength. The t e s t s have been c a r r i e d out by Partek Corporation's Concrete l a b o r a t o r y at Pargas, F i n l a n d .
