The influence of microstructure on the dimensional stability of lightweight aggregate concrete
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Date
1990
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of New Brunswick
Abstract
The m i c r o s t r u c t u r e of f o u r types o f manufactured
aggregates were s t u d i e d using a scanning e l e c t r o n microscope
and the r e s u l t s of t h i s work were used t o p r o v i d e an i n s i g ht
i n t o the d i m e n s i o n a l s t a b i l i t y of prisms made o f these
aggregates. The commercial names o f t h e f o u r types of
aggregates are S o l i t e , A a r d e l i t e , Poraver and L y t a g . The
dimensional s t a b i l i t y as determined from d r y i n g shrinkage
t e s t s (ASTM C157, C331) v a r i e d w i d e l y between t h e f o u r types
o f aggregate. The one w i t h the g r e a t e s t shrinkage was
A a r d e l i t e and t h e one w i t h the l e a s t was S o l i t e . The
r e l a t i o n s h i p of t h e s h r i n k a g e t o t h e p o r o s i t y of t h e
aggregate i s i m p o r t a n t . The p o r o s i t y ranges from t h e l i g h t e r
expanded glass ( w i t h i n t e r c o n n e c t e d pores) i n t h e case of
Poraver t o expanded shale produced by t h e r o t a r y k i l n method
t h a t has e s s e n t i a l l y n o n i n t e r c o n n e c t e d pores i n t h e case of
S o l i t e . I t i s t h e n a t u r e o f how p o r o s i t y i s a c h i e v e d r a t h er
than t h e degree o f p o r o s i t y t h a t i s i m p o r t a n t i n terms of
dimensional s t a b i l i t y.