Engineering Commons^™

Persistence And Mitigation Of Pfas Within Concrete Stormwater Drainage Infrastructure, Jason R. Mcdonald

Theses and Dissertations

The persistence, fate, and transport of per- and poly-fluoroalkyl substances, which have been shown to have adverse effects on human health, have been previously studied in environmental media such as soils and groundwater. This study investigates concrete, a medium that is rarely studied but frequently present in instances where PFAS originating from AFFF releases and spills have occurred. Used heavily throughout aviation firefighting, AFFF poses environmental hazards due to the length of PFAS degradation and toxicological implications, thus its classification as a forever chemical. From the very limited reports to date, studies have suggested very slow release from concrete, potentially …

Macro - And Microstructure Evaluation And Field Applications Of Concrete With Recycled Glass Pozzolan, Marija Krstic

Dissertations and Theses

Concrete is the most used material in the world, second only to water. Conventional concrete is produced with Portland cement (PC). The production of cement is an energy intensive operation that has raised significant environmental concerns, since one ton of cement generates an equal ton of CO₂. In the USA about 90 million tons of cement are used annually, with 3 million tons used in New York. Most contemporary concrete applications for buildings and infrastructure use high-performance concrete (HPC) mixtures which are produced by replacing a percentage of cement with supplementary cementitious materials (SCMs), consisting mainly of fly-ash …

Alkali-~Activated Fly Ash Binders: Feasibility As A Sustainable Alternative To Ordinary Portland Cement For Pre-~Cast Systems, Kimberly Sierra

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fresh, load-dependent, transport, and durability properties of alkali-activated fly ash mortars were studied. The influences of activator concentration, solution-to-binder ratio, curing condition, activator type, and sodium silicate-to-total solution ratio on the properties of the studied alkali-activated mortars were examined. This study was divided in two phases. The first phase dealt with the use of sodium hydroxide as the sole activator. The second phase of the study was divided into two parts, both of which used a combination of sodium hydroxide and sodium silicate as the activator solution. Part I of phase II used elevated temperature curing conditions, whereas part II …

Advanced Sustainable Concrete Materials For Infrastructure Applications, Kaylea Ann Smith

Masters Theses

"This study was performed to examine the effects of cement replaced by high volumes of Class C fly-ash on durability characteristics of concrete up to 120 days. Specifically, this study investigates possibility of amending American Society for Testing and Materials (ASTM) to allow High Volume Fly-ash (HVFA) concrete to cure until later ages prior to testing instead of 28 days. Five mix designs were compared with varying fly-ash percentages from 0 to 70% (by total cementitious mass). No other additives were present in any of the five mix designs. Water-to-cementitious ratio (w/cm) and total cementitious material remained constant as 0.40 …

An Investigation Of Waste Glass-Based Geopolymers Supplemented With Alumina, Mary U. Christiansen

Dissertations, Master's Theses and Master's Reports - Open

An increased consideration of sustainability throughout society has resulted in a surge of research investigating sustainable alternatives to existing construction materials. A new binder system, called a geopolymer, is being investigated to supplement ordinary portland cement (OPC) concrete, which has come under scrutiny because of the CO2 emissions inherent in its production.

Geopolymers are produced from the alkali activation of a powdered aluminosilicate source by an alkaline solution, which results in a dense three-dimensional matrix of tetrahedrally linked aluminosilicates. Geopolymers have shown great potential as a building construction material, offering similar mechanical and durability properties to OPC. Additionally, geopolymers have …

An Evaluation Of In-Stream Structures Designed To Provide Fish Habitat, Charles H. Call Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In-stream concrete structures were studied through model tests and river tests. The model studies indicated that four designs provided good habitat in the model stream. These structures were the inverted weir, the "V" structure, the slab with legs and the cylinder. Through the river studies it was determined that these structures did not influence enough of the total river area to be effective in providing good fish habitat. Also an appreciable amount of yearly maintenance would be required to free the structures from silting in, debris, and vandalism. The slab with legs was the only promising structure.