Graphene Oxide – A New Potential Nano Reinforcement
Master thesis
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http://hdl.handle.net/11250/2456229Utgivelsesdato
2017-06Metadata
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- Studentoppgaver (TN-ISØP) [1468]
Sammendrag
Graphene oxide (GO) is a new potential nano reinforcement in cementitious
composites. In previous research, graphene oxide has shown promising
potential for improving mechanical properties, and particularly the tensile
strength capacity. The thesis investigates the effect of GO on fresh cement
mortar (workability, air content, heat of hydration), microstructure (SEM &
EDS) and mechanical strength (Flexural -, compressive -, splitting tensile
strength) after 3,7, and 28 days of curing. These properties are studied by
introducing various dosages of GO combined with a constant content of
polycarboxylate (SP). The selected dosages of GO are 0.03 wt%, 0.05 wt%, and
0.2 wt% of the cement weight. The effects of two different types of GO have
been studied: Water dispersed- and fine powder concentrate GO. The results
show that the workability decreases correspondingly to the increasing content
of water dispersed GO. The heat of hydration is increased for both types of GO
which indicate a chemical reaction between GO and cement. The percent air
content is almost constant with a GO dosage of 0.03 wt% and 0.05 wt%, but is
increased from 3.2 % to 4.9 % with 0.2 wt% water dispersed GO. The increased
air content is an indirect outcome of poor compaction and workability. The
adverse effects of GO on fresh mortar will consequently influence the
mechanical properties. GO has the potential of accelerating the hydration
process and enhance the early mechanical strength (3 and 7 days), but has no
effect after 28 days of curing. Particularly for the highest content of water
dispersed GO, the adverse effect on the workability seems to diminish the
mechanical strength after 28 days. No distinct influence of GO on the
microstructure has been observed with SEM, except for the presence of GO
sheets verified by EDS.
Beskrivelse
Master's thesis in Industrial economics