Dissertation/Thesis Abstract

Soil-Geopolymer Mixtures Using Fly Ash and Recycled Concrete Aggregates (RCA) forRoad Base and Subbase Layers
by Odion, Daniel, M.S., University of Louisiana at Lafayette, 2019, 142; 13899418
Abstract (Summary)

The effectiveness of various materials as soil stabilizers has been investigated. While some are causing hazardous effects on the environment and are harmful to human health, others have no significant effect on the strength and durability on the affected soil. Out of several techniques available for improving the soil strength, our project aims at probing the efficacy of a low calcium geopolymer fly ash and recycled concrete aggregates (RCA) as a new ecofriendly binder material in enhancing the strength characteristics of high and low plastic soil. In the study, a geopolymer synthetized from low calcium fly ash and an alkaline solution made from sodium silicate and sodium hydroxide was used to stabilize these two soils from Louisiana. The soil samples were stabilized with fly ash and RCA at 5%, 15% and 25%, and their mechanical properties, shrinkage and durability were determined through unconfined compression test, indirect tensile test, drying shrinkage test and durability tests respectively. It was observed that unconfined compressive strength of soil-geopolymer system increases with the source material contents. Molar concentration of alkali activator, alkali-to-source material ratio and percent content of source material altogether affect the unconfined compressive strength of stabilized soil. The shrinkage for geopolymer was less than the soil cement mixture while the former was found to be more durable than later as well. Apparently, geopolymer with its high strength, low cost, low energy consumption and CO2 emissions during synthesis offers a better substitute to soil cement stabilized soil.

Indexing (document details)
Advisor: Khattak, Mohammad J.
Commitee: Sun, Xiaoduan, Zhang, Qian
School: University of Louisiana at Lafayette
Department: Civil Engineering
School Location: United States -- Louisiana
Source: MAI 82/1(E), Masters Abstracts International
Subjects: Engineering
Keywords: Geopolymer, Low calcium fly ash, RCA, Recycled concrete aggregates, Soil RCA geopolymer, Soil-geopolymer
Publication Number: 13899418
ISBN: 9798662485372
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