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Full-Text Articles in Engineering
Laboratory Evaluation Of Early-Age Concrete Comprising Type Il Cement And Natural Pozzolans, Battsagaan Ilch
Laboratory Evaluation Of Early-Age Concrete Comprising Type Il Cement And Natural Pozzolans, Battsagaan Ilch
Theses and Dissertations
The objective of this laboratory research was to investigate the effects of a higher water-cementitious materials ratio on selected properties of concrete mixtures comprising natural pozzolans. The scope of work included testing of six concrete mixtures, including one for each of three natural pozzolans at two water-cementitious materials ratios of 0.44 and 0.48 and one concrete mixture without pozzolan at a water-cementitious materials ratio of 0.44, which was treated as a baseline in this research. The stiffness and strength of each concrete mixture were measured at 1, 3, and 7 days using concrete specimens that were cast immediately after mixing. …
Lcc Mse Walls, Joel Smith
Lcc Mse Walls, Joel Smith
Theses and Dissertations
Lightweight cellular concrete (LCC) is mainly a mixture of water, cement, and foam bubbles. LCC generally has a cast density between 20-60 pcf and an air content between 49-84%. LCC is often used as a fill material because it has a low unit weight which reduces settlement. LCC is increasingly being considered as a backfill behind Mechanically Stabilized Earth (MSE) walls and embankments. Although engineers are using LCC in MSE walls or free face walls (MSE wall without the concrete panels or reinforcements), there is presently a lack of information regarding the performance and behavior of LCC to guide them. …
Use Of Vertical Electrical Impedance For Nondestructive Evaluation Of Concrete Bridge Decks, Enoch Thomas Boekweg
Use Of Vertical Electrical Impedance For Nondestructive Evaluation Of Concrete Bridge Decks, Enoch Thomas Boekweg
Theses and Dissertations
Nondestructive evaluation of civil infrastructure is increasingly important in the modern world to assess structures, predict longevity, and prescribe rehabilitation or replacement. For concrete bridge decks, one emerging diagnostic technique is vertical electrical impedance (VEI) testing, which is a nondestructive evaluation technology that quantitatively assesses the cover protection offered to steel reinforcement. Because VEI testing is still a relatively new approach to bridge deck inspection, additional studies are needed to increase the interpretability of VEI data. This thesis increases VEI interpretability with two advances. The first advance, presented in Chapter 2, offers an analytical model for interpreting VEI measurements of …
Delamination Detection In Concrete Using Disposable Impactors For Excitation, Anjali Narendra Patil
Delamination Detection In Concrete Using Disposable Impactors For Excitation, Anjali Narendra Patil
Theses and Dissertations
Delaminations in concrete bridge decks result primarily from corrosion of the reinforcing bars (or rebar). This corrosion leads to volumetric expansion of the rebar. When the rebar expands, concrete cracks, and there is a localized separation of the concrete cover from the underlying concrete. Impact-echo testing is an effective technique to map delaminations on concrete bridge decks. However, mapping speed is limited by necessary retrieval of the impactor for traditional tests. To achieve higher scanning speeds, it is advantageous to use both a non-contact measurement (air-coupled impact-echo) and disposable-impactor excitation. Disposable impactors have the potential advantage of achieving greater deck …
Deicer Usage On Concrete And Asphalt Pavements In Utah, Chase David Thomas
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 …
Analysis Of Selected Factors Affecting Concrete Cover Measurements On Bridge Decks, Jeffrey Ryan Hoki
Analysis Of Selected Factors Affecting Concrete Cover Measurements On Bridge Decks, Jeffrey Ryan Hoki
Theses and Dissertations
The objective of this research was to quantify the effects of selected parameters on the accuracy of concrete cover measurements on bridge decks. This research involved three full-factorial laboratory experiments each designed to investigate one of three primary variables. These primary variables included distance to a parallel adjacent bar, distance to a reinforcement intersection, and incorrect bar size input for the cover meter. Each experiment also involved four secondary variables known to affect cover readings. These secondary variables included actual cover depth, meter brand, antenna type, and bar size. Statistical analyses were performed to determine the significance of each factor. …
Freeze-Thaw Durability Of Pervious Concrete, Carson B. Demille
Freeze-Thaw Durability Of Pervious Concrete, Carson B. Demille
Theses and Dissertations
Although the use of pervious concrete is expanding, only a limited number of scholarly papers have been published on the resistance of pervious concrete to deterioration under frost action. Based on this need for additional research on the durability of pervious concrete in cold regions, the objective of this research was to evaluate the resistance of pervious concrete to degradation during freeze-thaw cycling under different soil clogging and water saturation conditions. The laboratory research associated with this project involved three primary measures of pervious concrete performance, including freeze-thaw durability, compressive strength, and permeability. Testing associated with freeze-thaw durability involved two …
Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton
Sensitivity Of Half-Cell Potential Measurements To Properties Of Concrete Bridge Decks, Thad Marshall Pinkerton
Theses and Dissertations
Half-cell potential testing has been recommended as a non-destructive method for assessing the corrosion potential of reinforcing steel in concrete bridge decks. The technique is particularly useful because it can be utilized to evaluate the probability of corrosion before damage is evident at the surface of a bridge deck. The specific objective of this research was to quantify the effects of age, chloride concentration, concrete cover thickness, spatial position, temperature, and presence or condition of epoxy coating on half-cell potential measurements of concrete bridge decks typical of those in Utah. The laboratory testing associated with this research followed a full-factorial …
Biomass And Coal Fly Ash In Concrete: Strength, Durability, Microstructure, Quantitative Kinetics Of Pozzolanic Reaction And Alkali Silica Reaction Investigations., Shuangzhen Wang
Theses and Dissertations
Biomass represents an important sustainable energy resource, with biomass-coal cofiring representing among the most effective and cost efficient CO2 reduction strategies. Fly ash generated during coal combustion represents a technically advantageous, inexpensive, and environmentally beneficial admixture in concrete production, partially replacing cement. However, strict interpretation of American Society of Testing and Materials (ASTM) and American Concrete Institute (ACI) standards prohibits use of fly ashes from any source other than coal in concrete production; therefore, fly ash from biomass coal cofiring is excluded from use in concrete. This dissertation discusses biomass impacts on concrete properties through experiments conducted on several combinations …
Rectification Of 2-D To 3-D Finite Element Analysis In Buried Concrete Arches Under Discrete Loading, Adam D. Aagard
Rectification Of 2-D To 3-D Finite Element Analysis In Buried Concrete Arches Under Discrete Loading, Adam D. Aagard
Theses and Dissertations
Construction of tunnels and small- to medium-span bridges is a $12 billion per year industry in the United States, with a significant portion going into buried arch structures. Notwithstanding such expenditure, modern arch design and construction, in many cases, is highly conservative. This is because the closed-form solutions used by most designers today do not correctly account for soil-structure interaction. In fact, soil-structure interaction makes a closed form solution impossible. With the advent of high power computers in recent years, some designers have turned to finite element (FE)modeling as the main vehicle of analysis. Such numerical procedures provide an accurate …
In-Situ Testing Of A Carbon/Epoxy Isotruss Reinforced Concrete Foundation Pile, Sarah Richardson
In-Situ Testing Of A Carbon/Epoxy Isotruss Reinforced Concrete Foundation Pile, Sarah Richardson
Theses and Dissertations
This thesis focuses on the field performance of IsoTruss®-reinforced concrete beam columns for use in driven piles. Experimental investigation included one instrumented carbon/epoxy IsoTruss®-reinforced concrete pile (IRC pile) and one instrumented steel-reinforced concrete pile (SRC pile) which were driven into a clay profile at a test site. These two piles, each 30 ft (9 m) in length and 14 in (36 cm) in diameter, were quasi-statically loaded laterally until failure. Behavior was predicted using three different methods: 1) a commercial finite difference-based computer program called Lpile; 2) a Winkler foundation model; and, 3) a simple analysis based on fundamental mechanics …