Abstract
In the present study, the mechanical and durability properties of silica nanoparticle (SNP)-incorporated fly ash (FA) concrete mix were examined after 365 days of exposure. The dosages of FA replaced by cement in the present study were 30%, 40%, and 50%, while 3% SNPs were added by the weight of cement in the FA incorporated mix. For a comparison of SNPs with silica fume (SF), 6% SF was added (by the weight of cement) and entire casting was performed at a constant water to binder (w/b) ratio of 0.29. The present work is the extension of a previous study wherein durability properties of the same mixes were reported for up to 180 days of exposure. Compressive strength results show that in the presence of SNPs, the enhancement in compressive strength was in the range of 10–14%, while, in presence of SF, 8–10% of the enhancement was observed as compared to control. However, exposed samples in a carbonation environment showed that the compressive strength of the control and SF incorporated mix increased, while SNP-incorporated samples showed negligible enhancement. Further, sulphate exposed mix show that compressive strength decreases, however, the SNP-incorporated mix showed the lowest reduction compared to other mixes. Therefore, the study shows that the SNP-incorporated mix has higher mechanical properties and more durability compared to other mixes in a severe environment.
Highlights
Extensive utilization of concrete by the construction industries has led to the enormous consumption of cement, and it is necessary to preserve the buildings in their original forms for a long time with sustainable material
40 fly ash (FA) and 50 FA concrete specimens exhibit higher compressive strength enhancement as compare to 30 FA specimens, showing more carbonation as the porosity increases with the higher dosages of FA, and, accelerated carbonation occurred
Concrete samples exposed in sulphate solution show strength reduction since, during the sulphate attack, sulphate ions react with the CH and AFm phases, which leads to the formation of ettringite and gypsum, resulting in expending in pressure and cracks
Summary
Extensive utilization of concrete by the construction industries has led to the enormous consumption of cement, and it is necessary to preserve the buildings in their original forms for a long time with sustainable material. Researchers have been developing sustainable concrete using less energy and supplementary cementitious materials to reduce the carbon footprint of cement (Guterres, 2017). 2021 investigated the microscopic performances of metakaolin (MK) containing a UHPC matrix using steam curing They have reported that MK reaction kinetics increased with higher curing temperature; cement hydration rate reduced. Zhang et al, 2021 have investigated the role of steam curing in the performance of PC incorporating self-ignited coal gangue (CG) particles They have reported that steam curing can significantly activate the pozzolanic reaction of the CG particle and alleviate the negative impact arising from CG addition.
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