Engineering Commons^™

Application Of Image Processing And Finite Element Analysis In Modeling Chloride Diffusion In Concrete, Arash Razmjoo

All Dissertations

Utilizing numerical simulation models to predict the long-term mechanical and transport behavior of concrete structures is becoming increasingly popular. The majority of these models have been developed using laboratory test data that consider concrete as a homogeneous material with spherical aggregates. These models could not be a represented of real concrete because it has no primitive shaped aggregate besides that the porosity size and distribution varies from point to point. In this study a novel method for more accurate prediction of the chloride diffusion in concrete was developed. A general framework of the quantitative computed tomography (QCT) and finite element …

Deicer Usage On Concrete And Asphalt Pavements In Utah, Chase David Thomas

Theses and Dissertations

The objectives of this research were to 1) compile winter maintenance data for the Utah Department of Transportation (UDOT) to directly compare concrete and asphalt pavements with regards to deicer usage and 2) determine if there is a statistical difference in deicer usage on concrete and asphalt pavements. To this end, three data sources were consulted for this research: Material Maintenance Quality Assurance (MMQA) database, UDOT road database, and Google Maps. The final compiled data set prepared for analysis in this research contained deicer quantities by deicer type, pavement surface areas by pavement material type, traffic, longitude, latitude, and elevation …

Miniature Concrete Prism Test - A New Test Method For Evaluating The Asr Potential Of Aggregates, The Effectiveness Of Asr Mitigation And The Job Mixture, Enamur Latifee

All Dissertations

Existing test methods to characterize ASR potential of aggregates and mitigation ability of supplementary cementing materials such as the Accelerated Mortar Bar Test (AMBT) and the Concrete Prism Test (CPT) are widely accepted in the industry. Although, the AMBT is a rapid test, the results from this test can be unreliable, particularly with certain types of aggregates. The CPT is considered as a more reliable test; however, the duration of this test method renders it impractical for routine usage in the industry to screen deleterious materials or inefficient ASR mitigation measures. This research presents a new test method-Miniature Concrete Prism …

Performance Of Reinforced Concrete Beams Strengthened With Mechanically-Fastened Composite System Under Corrosive Environment, Amna Zaid Suwaid Al Nassibi

Theses

This study examines the effects of corrosion exposure on the flexural response of reinforced concrete (RC) beams strengthened with a powder-actuated fastened (PAF) composite system. Twenty-one RC beams were constructed and tested to failure under four-point bending. The corroded beams were subjected to 30, 60, and 100 days of accelerated corrosion that corresponded to measure tensile steel mass losses of 6, 11 and 18% respectively. Other test parameters included width of fiber reinforced polymer (FRP) composite strip, fastener length, and number of fasteners rows.

For the non-corroded beams, the PAF-FRP system resulted in up to 24% increase in beam flexural …

Simplified Tools For Performance-Based Design Of Reinforced Concrete Frames Exposed To Fire, Salah El-Din F. El-Fitiany

Electronic Thesis and Dissertation Repository

Fire safety of Reinforced Concrete (RC) buildings is an important design aspect that ensures structural integrity during fire events. As new codes are moving towards performance based design, practitioners are in need of rational design tools to assess the strength and serviceability of individual RC elements and the structure as a whole during fire. This thesis provides such tools for RC frames.

A previously developed sectional analysis method is extended to cover RC beams subjected to fire from three sides. An extensive parametric study is conducted to evaluate the equivalent stress-block parameters at elevated temperatures.

A novel method to track …

Experimental And Numerical Investigations On Bond Durability Of Cfrp Strengthened Concrete Members Subjected To Environmental Exposure, Haider Al-Jelawy

Electronic Theses and Dissertations

Fiber reinforced polymer (FRP) composites have become an attractive alternative to conventional methods for external-strengthening of civil infrastructure, particularly as applied to flexural strengthening of reinforced concrete (RC) members. However, durability of the bond between FRP composite and concrete has shown degradation under some aggressive environments. Although numerous studies have been conducted on concrete members strengthened with FRP composites, most of those studies have focused on the degradation of FRP material itself, relatively few on bond behavior under repeated mechanical and environmental loading. This thesis investigates bond durability under accelerated environmental conditioning of two FRP systems commonly employed in civil …

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 …

Assessing Corrosion Damage In Post -Tensioned Concrete Structures Using Acoustic Emission & A Preliminary Investigation Of Biopolymer Doped Cement Mortar For Use In Structural Restoration, Aditya Appalla

Theses and Dissertations

A sizeable portion of the civil infrastructure is made from concrete. An estimate shows that about 7 billion cubic meters of concrete is made annually worldwide. With the deterioration of the infrastructure due to aging or external factors, significant monetary and technological investment is needed for condition evaluation, maintenance and repair. Two areas that account for a considerable portion of this investment are condition evaluation for maintenance of corroded concrete structures and mortar patching for repair and rehabilitation.

The primary method of evaluation of a structure is by visual inspection. But this method is limited as some crucial areas in …

Kelvin Probe Electrode For Contactless Potential Measurement On Concrete-Properties And Applications, Michael Thomas Walsh

USF Tampa Graduate Theses and Dissertations

The practical feasibility of using a Kelvin Probe as a novel reference electrode in the measurement of both potential and polarization pulse response of reinforcing steel in concrete is demonstrated. Potential values measured using a KP reflect greater stability and repeatability than can typically be attained with conventional reference electrodes. Duplicate reinforced concrete beam test specimens with well-differentiated centrally corroding rebar segments were analyzed using both the Kelvin Probe (KP) and a conventional Saturated Calomel Electrode (SCE). Potential profile maps were developed using potential values recorded under static conditions with both the SCE and the KP. Nominal polarization resistance was …