| Effect of Concrete Waste on Compressive Strength and
Microstructure Development of Ceramic Geopolymer Pastes |
Ahmed S. Ouda1, 2, * and Khaled L. Abdel-Aal 2
Pages : 146-154
DOI : 10.1080/0371750X.2019.1640637 |
| Abstract |
| Ceramic industry generates a large amount of wastes, which pollutes and damages
the environment. This paper presents the effects of concrete waste incorporating
dolomite aggregate on ceramic-based geopolymer pastes in terms of
microstructure and compressive strength. Recently, attention has been drawn to
the use of geopolymer technology in the production of building units. Geopolymers
were prepared from alkali activation of ceramic waste by 6%, 8%, 10% and 12%
NaOH. To enhance the mechanical properties, alkali-activated ceramic geopolymer
with 10% and 12% NaOH was partially substituted with concrete waste containing
dolomite coarse aggregate at proportions of 5%, 10%, 15%, 20% and 30% by weight.
Likewise, other geopolymer mixtures were manufactured by replacing ceramics
with 5%, 10%, 15%, 20% and 30% calcined concrete waste at 850oC. Water/binder
ratio as well as compressive strength of all mixtures was determined at 1, 7, 14
and 28 days. Phase composition and microstructure of geopolymer were identified
using Fourier transform infrared spectroscopy and scanning electron microscopy
techniques. Incorporation of 10% concrete waste and 20% calcined concrete waste
enhanced the compressive strength and the microstructure of ceramic geopolymer
pastes, while embedding extra amounts led to adverse effects.
[Keywords: Geopolymers, Recycled concrete waste, Alkali-activated materials,
Mechanical properties, Microstructure] |
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