Effect of Curing Time on the Performance of Fly Ash Geopolymer-Stabilized RAP Bases

Jallu, Maheshbabu and Saride, Sireesh and Arulrajah, Arul and Challapalli, Subrahmanyam and Evans, Robert (2021) Effect of Curing Time on the Performance of Fly Ash Geopolymer-Stabilized RAP Bases. Journal of Materials in Civil Engineering, 33 (3). 04021001. ISSN 0899-1561

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Abstract

The long-term integrity of fly ash (FA) geopolymer-stabilized high-percentage reclaimed asphalt pavement (RAP) in the pavement base layer was investigated in this research. The FA geopolymer-stabilized RAP and virgin aggregate (VA) mixes were studied as an economical and durable alternative to 100% VA bases, with an emphasis on the influence of curing time. The maturity age of FA is usually set as 28 days, similar to traditional portland cement. However, due to partial pozzolanic reactions, though geopolymerized, the dilution of partial FA particles does not fully play its role at 28 days of curing time. Hence, this is not a realistic reference time for predicting the service life of FA geopolymer-stabilized aggregate blends. Therefore, a detailed experimental investigation was undertaken to evaluate the ultimate strength, durability, and microstructural characteristics of four distinct FA geopolymer-stabilized RAP:VA blends for a long-term ambient curing time up to 270 days. In this study, the long-term cured specimens showed significant improvement in mechanical strength and stiffness, yielding lower permanent deformations. It was noticed that only about 12% and 40% average unconfined compressive strength (UCS) could be achieved in 7- and 28-day cured specimens, respectively, with reference to their ultimate strength at 270 days. Hence, to examine the microstructural characteristics of powdered FA geopolymer blends, X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), and Fourier transform-infrared spectroscopy (FT-IR) studies were performed. The test results revealed that the consumption of reactive metal ions was continued for an extended period under a controlled curing regime, which resulted in improved mechanical strength and durability of the solidified product.

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IITH Creators:
IITH CreatorsORCiD
Jallu, M.UNSPECIFIED
Saride, S.UNSPECIFIED
Challalli, S.UNSPECIFIED
Item Type: Article
Uncontrolled Keywords: Aggregates; Compressive strength; Curing; Durability; Energy dispersive spectroscopy; Fly ash; Fourier transform infrared spectroscopy; Geopolymers; Metal ions; Metals; Portland cement; Scanning electron microscopy; Energy dispersive X ray spectroscopy; Experimental investigations; Fourier transform infra red (FTIR) spectroscopy; Micro-structural characteristics; Permanent deformations; Reclaimed asphalt pavements; Strength and stiffness; Unconfined compressive strength
Subjects: Chemistry
Chemistry > Inorganic chemistry
Chemical Engineering
Divisions: Department of Chemistry
Depositing User: . LibTrainee 2021
Date Deposited: 18 Jun 2021 09:58
Last Modified: 18 Jun 2021 09:58
URI: http://raiith.iith.ac.in/id/eprint/7931
Publisher URL: http://doi.org/10.1061/(ASCE)MT.1943-5533.0003581
OA policy: https://v2.sherpa.ac.uk/id/publication/11572
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