Date of Defense

12-11-2024 6:00 PM

Location

F3-134

Document Type

Thesis Defense

Degree Name

Master of Science in Civil Engineering (MSCE)

College

COE

Department

Civil and Environmental Engineering

First Advisor

Dr. Hilal El-Hassan

Keywords

Masonry, geopolymer, recycled aggregates, units, mortars, walls, slag, fly ash, performance evaluation, analytical models.

Abstract

Sustainable construction materials have been commonly adopted to replace primary components in concrete, namely cement and natural aggregates. Yet, the combined effect of utilizing geopolymers and recycled aggregates in masonry, one of the oldest construction products and methods in the world, has not been widely investigated. Therefore, this thesis evaluates the feasibility of utilizing recycled aggregates in slag-fly ash blended geopolymer concrete masonry units and mortars for masonry wall construction applications. A blend of slag and fly ash served as the precursor binding material. A sodium-based alkaline solution was employed to activate the blended binder. Natural aggregates were substituted with recycled aggregates at 25, 50, 75, and 100% mass replacement rates. The current work was divided into three major phases. In the first phase, the physical and mechanical properties of geopolymer concrete masonry units made with recycled coarse aggregates were assessed. The second phase investigated the fresh, mechanical, physical, and durability properties of geopolymer masonry mortars made with recycled fine aggregates. Additionally, environmental and economic impact assessments were conducted on the developed masonry unit and mortar mixes to select the optimal mix based on multiple performance criteria. Finally, the third phase entailed examining the mechanical behavior of geopolymer concrete masonry prismatic walls made with recycled aggregates. Results emphasized the potential viability of geopolymer concrete masonry units, mortars, and prismatic walls made with recycled aggregates to be used for structural purposes. Such sustainable masonry products were able to attain comparable or superior mechanical properties to traditional cement-based masonry counterparts made with natural aggregates. Simultaneously, they would reduce carbon dioxide emissions, valorize recycled aggregates, and conserve natural resources. Analytical models were also developed to correlate the different properties of masonry units and mortars and to predict the mechanical behavior of masonry prismatic walls based on the compressive strength of their components, i.e., masonry units and mortars.

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Nov 12th, 6:00 PM

PERFORMANCE EVALUATION OF GEOPOLYMER CONCRETE MASONRY UNITS AND GEOPOLYMER MASONRY MORTARS INCORPORATING RECYCLED AGGREGATES

F3-134

Sustainable construction materials have been commonly adopted to replace primary components in concrete, namely cement and natural aggregates. Yet, the combined effect of utilizing geopolymers and recycled aggregates in masonry, one of the oldest construction products and methods in the world, has not been widely investigated. Therefore, this thesis evaluates the feasibility of utilizing recycled aggregates in slag-fly ash blended geopolymer concrete masonry units and mortars for masonry wall construction applications. A blend of slag and fly ash served as the precursor binding material. A sodium-based alkaline solution was employed to activate the blended binder. Natural aggregates were substituted with recycled aggregates at 25, 50, 75, and 100% mass replacement rates. The current work was divided into three major phases. In the first phase, the physical and mechanical properties of geopolymer concrete masonry units made with recycled coarse aggregates were assessed. The second phase investigated the fresh, mechanical, physical, and durability properties of geopolymer masonry mortars made with recycled fine aggregates. Additionally, environmental and economic impact assessments were conducted on the developed masonry unit and mortar mixes to select the optimal mix based on multiple performance criteria. Finally, the third phase entailed examining the mechanical behavior of geopolymer concrete masonry prismatic walls made with recycled aggregates. Results emphasized the potential viability of geopolymer concrete masonry units, mortars, and prismatic walls made with recycled aggregates to be used for structural purposes. Such sustainable masonry products were able to attain comparable or superior mechanical properties to traditional cement-based masonry counterparts made with natural aggregates. Simultaneously, they would reduce carbon dioxide emissions, valorize recycled aggregates, and conserve natural resources. Analytical models were also developed to correlate the different properties of masonry units and mortars and to predict the mechanical behavior of masonry prismatic walls based on the compressive strength of their components, i.e., masonry units and mortars.