91 research outputs found
Novel syntactic foams made of ceramic hollow micro-spheres and starch: theory, structure and properties
Novel syntactic foams for potential building material applications were developed using starch as binder
and ceramic hollow micro-spheres available as waste from
coal-fire power stations. Foams of four different microsphere size groups were manufactured with either pre- or post-mould gelatinization process. They were of ternary
system including voids with a foam density range of
approximately 0.33–0.44 g/cc. Compressive failure
behaviour and mechanical properties of the manufactured
foams were evaluated. Not much difference in failure
behaviour or in mechanical properties between the two
different processes (pre- and post-mould gels) was found
for a given binder content. Compressive failure of all
syntactic foams was of shear on plane inclined 45 to
compressive loading direction. Failure surfaces of most
syntactic foams were characterized by debonded microspheres.
Compressive strength and modulus of syntactic foams were found to be dependant mainly on binder content
but mostly independent of micro-sphere size. Some
conditions of relativity arising from properties of constituents leading to the rule of mixtures relationships for compressive strength and to understanding of compressive/transitional failure behaviour were developed. The developed relationships based on the rule of mixtures were partially verified. Some formation of starch webs on failure surfaces was discussed
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