Date of Defense
30-4-2025 2:00 PM
Location
F3-223
Document Type
Dissertation Defense
Degree Name
Doctor of Philosophy in Civil Engineering
College
COE
Department
Civil and Environmental Engineering
First Advisor
Dr. Hilal El-Hassan
Keywords
Concrete, volcanic ash, calcium carbide residue, carbonation curing, carbon storage.
Abstract
The production and use of cement and concrete is a major contributor to numerous environmental problems, primarily centered around high carbon emissions, extensive resource depletion, and vast waste generation. This thesis aims to develop and characterize low-carbon concrete by using volcanic ash (VA) and calcium carbide residue (CCR) as partial cement substitutes while exposing the cementitious composite to accelerated carbonation curing. The study is a multi-level assessment of the incorporated materials and curing method divided into four phases. The first stage studied and optimized the CCR content and carbonation curing parameters of carbonation-cured concrete. It was revealed that using 5% CCR was optimum for strength, whereas up to 10% CCR was optimum for carbon sequestration. Meanwhile, prolonging the carbonation curing duration (up to 40 hours) and increasing the CO2 pressure (up to 5 bars) improved all properties.
The second phase aimed to optimize the mix design parameters of cementitious composites containing VA and dune sand. Using the Taguchi-TOPSIS hybrid method, the optimum mix was determined to have a binder content of 500 kg/m3, a water-to-binder ratio of 0.5, a dune sand content of 20%, a VA content of 20%, and a superplasticizer content of 0.75%. The optimum mix was validated experimentally and had superior fresh, mechanical, and durability properties to other mixes. Phase three investigated the ternary system replacing cement with VA and CCR. The inclusion of CCR alone was more impactful on the fresh properties than VA, decreasing the flow and prolonging the setting time. Meanwhile, incorporating VA and CCR extended the setting time except for the mix made with 20% VA and 5% CCR. At these replacement levels, the highest mechanical and durability performance was achieved.
The fourth phase optimized the mix design and process parameters of carbonation-cured concrete containing VA and CCR. The carbonation regime involving 20-hour initial air curing and 4-hour carbonation rendered the highest carbon sequestration at 5-40% CCR and 0-5% VA. Conversely, the best early-age performance was reported for a binder comprising 0-20% CCR and 0-5% VA. Meanwhile, the optimum 28-day performance was for a mix made with a binder incorporating 0-5% CCR and 10-35% VA and exposed to a carbonation scheme of 4-hour initial air curing and 20-hour carbonation. This thesis develops innovative low-carbon concrete solutions by integrating recycled waste materials with carbonation curing. These composites address multiple environmental challenges in a single approach, contributing to reduced carbon emissions and resource conservation.
Included in
DEVELOPMENT OF LOW-CARBON CEMENTITIOUS COMPOSITES WITH VOLCANIC ASH AND CALCIUM CARBIDE RESIDUE USING CARBONATION CURING
F3-223
The production and use of cement and concrete is a major contributor to numerous environmental problems, primarily centered around high carbon emissions, extensive resource depletion, and vast waste generation. This thesis aims to develop and characterize low-carbon concrete by using volcanic ash (VA) and calcium carbide residue (CCR) as partial cement substitutes while exposing the cementitious composite to accelerated carbonation curing. The study is a multi-level assessment of the incorporated materials and curing method divided into four phases. The first stage studied and optimized the CCR content and carbonation curing parameters of carbonation-cured concrete. It was revealed that using 5% CCR was optimum for strength, whereas up to 10% CCR was optimum for carbon sequestration. Meanwhile, prolonging the carbonation curing duration (up to 40 hours) and increasing the CO2 pressure (up to 5 bars) improved all properties.
The second phase aimed to optimize the mix design parameters of cementitious composites containing VA and dune sand. Using the Taguchi-TOPSIS hybrid method, the optimum mix was determined to have a binder content of 500 kg/m3, a water-to-binder ratio of 0.5, a dune sand content of 20%, a VA content of 20%, and a superplasticizer content of 0.75%. The optimum mix was validated experimentally and had superior fresh, mechanical, and durability properties to other mixes. Phase three investigated the ternary system replacing cement with VA and CCR. The inclusion of CCR alone was more impactful on the fresh properties than VA, decreasing the flow and prolonging the setting time. Meanwhile, incorporating VA and CCR extended the setting time except for the mix made with 20% VA and 5% CCR. At these replacement levels, the highest mechanical and durability performance was achieved.
The fourth phase optimized the mix design and process parameters of carbonation-cured concrete containing VA and CCR. The carbonation regime involving 20-hour initial air curing and 4-hour carbonation rendered the highest carbon sequestration at 5-40% CCR and 0-5% VA. Conversely, the best early-age performance was reported for a binder comprising 0-20% CCR and 0-5% VA. Meanwhile, the optimum 28-day performance was for a mix made with a binder incorporating 0-5% CCR and 10-35% VA and exposed to a carbonation scheme of 4-hour initial air curing and 20-hour carbonation. This thesis develops innovative low-carbon concrete solutions by integrating recycled waste materials with carbonation curing. These composites address multiple environmental challenges in a single approach, contributing to reduced carbon emissions and resource conservation.