Effect of Curing Time on the Performance of Fly Ash Geopolymer-Stabilized RAP BasesSource: Journal of Materials in Civil Engineering:;2021:;Volume ( 033 ):;issue: 003::page 04021001-1Author:Maheshbabu Jallu
,
Sireesh Saride
,
Arul Arulrajah
,
Subrahmanyam Challapalli
,
Robert Evans
DOI: 10.1061/(ASCE)MT.1943-5533.0003581Publisher: ASCE
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.
|
Collections
Show full item record
contributor author | Maheshbabu Jallu | |
contributor author | Sireesh Saride | |
contributor author | Arul Arulrajah | |
contributor author | Subrahmanyam Challapalli | |
contributor author | Robert Evans | |
date accessioned | 2022-01-31T23:32:16Z | |
date available | 2022-01-31T23:32:16Z | |
date issued | 3/1/2021 | |
identifier other | %28ASCE%29MT.1943-5533.0003581.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl1/handle/yetl/4269895 | |
description 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. | |
publisher | ASCE | |
title | Effect of Curing Time on the Performance of Fly Ash Geopolymer-Stabilized RAP Bases | |
type | Journal Paper | |
journal volume | 33 | |
journal issue | 3 | |
journal title | Journal of Materials in Civil Engineering | |
identifier doi | 10.1061/(ASCE)MT.1943-5533.0003581 | |
journal fristpage | 04021001-1 | |
journal lastpage | 04021001-10 | |
page | 10 | |
tree | Journal of Materials in Civil Engineering:;2021:;Volume ( 033 ):;issue: 003 | |
contenttype | Fulltext |