Civil and Environmental Engineering Commons^™

Continuous Moisture Measurement During Pavement Foundation Construction: Laboratory Measurements, Isaac Esteban Zuniga

Open Access Theses & Dissertations

Moisture content directly affects all properties of subgrade materials. A rapid, continuous, and accurate technique to determine moisture content during subgrade construction is the next step needed to improve the mechanistic-based quality of pavement foundations. In this study, six geomaterials were compacted to standard/modified proctor specifications and subjected to laboratory measurements to study the variations in their electromagnetic and electric properties with moisture content. The relationships between the seismic modulus, unconfined compressive strength, lightweight deflectometer, and moisture content for the same geomaterials were also established. Large-scale replicate specimens were also compacted and subjected to numerous measurements. The dielectric constant measured …

Geospatial Relationship Of Intelligent Compaction Measurement Values With In-Situ Testing For Quality Assessment Of Geomaterials, Luis Alberto Lemus

Open Access Theses & Dissertations

The implementation of Intelligent Compaction (IC) in the construction of transportation infrastructure as a tool for quality control of compacted geomaterials has attracted the attention of a number of highway agencies. Compaction quality has been conventionally assessed using density, and to a less extent, modulus-based spot measurements at selected locations along the roadway section. While spot measurements do not provide a thorough rendition of the level of compaction of the roadway, IC technology is effective in meeting full coverage requirements. IC roller measurements are accelerometer-based measurements recording machine-ground interaction assumed to be indicative of the stiffness of the compacted geomaterial. …

Back Calculation Of Intelligent Compaction Data For Mechanical Properties Of Soil System, Afshin Gholamy

Open Access Theses & Dissertations

For national economy, it is very important to have a reliable infrastructure. Because of this, all over the world, new roads are constantly being built and old roads are being maintained and, if necessary, expanded and/or repaired. Building a good quality road is very expensive, it costs several million dollars per kilometer. It is therefore crucial to make sure that the newly built and newly repaired roads are sufficiently stiff - so that they can withstand the predicted volume of traffic for a sufficient number of years. Current methods of estimating the stiffness are time-consuming and labor-consuming. The most accurate …

Onshore-Offshore Velocity Models North Of The Mendocino Triple Junction In Northern California, Alan Jacquez

Open Access Theses & Dissertations

The Mendocino Triple Junction (MTJ) marks the boundary where the Gorda plate, North American Plate, and Pacific Plate meet, separating the Cascadia subduction zone to the North from transform tectonics of the San Andreas plate boundary. This actively deforming region experiences high seismic activity and young geological features. Here we examine offshore and onshore seismic wide-angle reflection and refraction data north of the MTJ crossing the Cascadia subduction zone from offshore northern California to the Western edge of the Sierra Nevada. We image subsurface structures in this region by creating P-wave velocity models using datasets collected in 1993 to 1994 …

Effects Of Gradation And Moisture Content On Resistivity Of Mechanically Stabilized Earth Wall Backfill Materials, Jose Luis Arciniega

Open Access Theses & Dissertations

The service life of mechanically stabilized earth (MSE) walls depends on the corrosion rate of the metallic reinforcement used in their construction. The resistivity of the backfill aggregates needs to be measured accurately in order to estimate realistically the corrosion rate of the reinforcement. Resistivity testing is usually performed using the traditional soil box on the portion of the aggregates that passes a No. 10 or No. 8 sieve to either select or reject the backfill. For a more reasonable characterization of the corrosivity of coarse backfills, it is desirable to use their actual gradations. To that end, several resistivity …

Evaluation Of Recycled Gypsum Application Dosages To Enhance The Water Infiltration Rate At Water Retention Ponds, Jorge Luis Navarrete

Open Access Theses & Dissertations

The retention ponds play central role for efficient collection, removal, and drainage of rainfall runoff from surrounding streets to minimize flooding and damage. However, low percolating retention ponds may result in an extended ponding of water, abundance bacteria accumulations, mosquito breeding, environmental hazards, among others. The presence of clayey soils and soil sodicity reduces infiltration rates of retention ponds. To enhance the infiltration rate of ponds, it is proposed to use recycled gypsum (RG), as a soil amendment in retention ponds consisting of clayey soils to enhance low infiltration rates.

To evaluate the influence of RG in clayey soils as …

Evaluation Of Mechanical Parameters Of Contaminated Road Base And Railway Ballast, Prajwol Tamrakar

Open Access Theses & Dissertations

This Dissertation comprises two topics in the area of transportation geotechnics that focus on the evaluation of stiffness parameters of contaminated road base and railway ballast. The abstracts of these two studies are provided in the following two paragraphs.

The performance of a flexible pavement depends on the mechanical characteristics of its unbound granular base layer. The mechanical characteristics such as stiffness and deformation resistance depend on many factors such as the material gradation, fines content, moisture content, physical properties of coarse aggregate and more. The base materials are often contaminated by the excessive fines that is caused by improper …

The Use Of Remote Sensing Technologies And Models To Study Pollutants In Pdn Region, Suhail Mahmud

Open Access Theses & Dissertations

Using a suite of modeling techniques and instrumentation we study the atmospheric pollutants in the PdN Region. The first objective of this work was to measure hemi-spherically integrated, spectrally resolved solar photon flux (actinic flux) between the wavelengths 300 and 700 nm, and use the measured actinic flux to improve air quality simulations. Actinic flux was measured in the PdN region in order to calculate photolysis rate coefficients for different pollutants. The improved photolysis rate coefficients were then integrated into a photochemical air quality model (CAMx) in order to improve air quality forecasting. We present the simulations performed for a …

Evaluating Methods Of Field-Based 3d Visualization And Their Application To Mapping Metamorphic Terranes: An Example From The Panamint Mountains, California, Jade Ashley Brush

Open Access Theses & Dissertations

Field geology has traditionally relied on 2D, paper-based workflows, but digital mapping techniques are rapidly replacing these outdated methods because they allow for more efficient and accurate mapping. This research applies digital mapping techniques and two terrestrially-based 3D visualization technologies, photogrammetry and Light Detection and Ranging (LiDAR), to the study of metamorphic terranes in the Panamint Mountains, California. This study reports on the spatial accuracy of TINs (triangulated irregular networks) generated from both photogrammetry and ground-based LiDAR using a terrestrial laser scanner (TLS) and discusses how spatial accuracy can be increased. Two levels of comparison were used to test spatial …

Performance Life Of Various Hot Mix Asphalt Mixtures In Texas, Danniel David Rodriguez

Open Access Theses & Dissertations

Typically, pavement engineers in subjectively estimate the service lives of various hot-mix asphalt (HMA) mixtures as part of the life-cycle cost analysis considering the staged design and rehabilitation of flexible pavements. This study proposes the performance lives for the various dense-graded (conventional) mixtures, stone-matrix asphalts (SMA), permeable friction courses (PFC), performance design mixtures and other mixtures placed in Texas. A necessary and significant aspect of the approach involved data mining and merging several pavement management databases (Letting Database, DCIS and PMIS) to obtain mixture longevity data along with historical PMIS information. The product of the linking process resulted in the …

Why Ricker Wavelets Are Successful In Processing Seismic Data: Towards A Theoretical Explanation, Afshin Gholamy Salehabady

Open Access Theses & Dissertations

In many engineering applications ranging from engineering seismology to petroleum engineering and civil engineering, processing seismic data plays a key role. In processing seismic data, it turns out to be very efficient to describe the signal's spectrum as a linear combination of Ricker wavelet spectra.

In this Thesis, we provide a possible theoretical explanation for this empirical efficiency. Specifically, signal propagation through several layers is discussed, and it is shown that the Ricker wavelet is the simplest non-trivial solution for the corresponding data processing problem, under the condition that the described properties of the approximation family are satisfied.

Model Fusion: A New Approach To Processing Heterogeneous Data, Omar Ochoa

Open Access Theses & Dissertations

In many practical situations, it is necessary to extract

information from data of different types. For example, in geosciences, several sources of data can be used to determine the interior structure of the earth: the first arriving waves from earthquakes and from man-made sources, measurements of the earth's gravity field, measurements of the dispersion of surface waves generated by earthquakes, etc. At present, most existing data processing techniques deal only with data of one type.

A joint use of all the information derived from multiple types of data sources is an important theoretical and practical challenge. Such a joint use …

Impact Of Moisture Content And Density On Stiffness-Based Acceptance Of Geomaterials, Lourdes Guadalupe Pacheco

Open Access Theses & Dissertations

Modulus-based quality management of compacted layers has been considered by a number of highway agencies. Even though simple in concept, the paradigm shift from density to modulus for quality acceptance has generated some technical and institutional challenges. One of these complications is that for a given density, the modulus can vastly vary depending on the moisture content at the time of compaction and at the time of acceptance. The results of a systematic study carried out to qualify and quantify the impact of compaction moisture content, moisture content at the time of field testing and density on the modulus and …

Applicability Of Mepdg For India Based On Texas Pavement And Environmental Conditions, Vamsi Krishna Pinnamaneni

Open Access Theses & Dissertations

The Indian pavement design guide uses empirical models which were adopted and modified from US design guides. As with any empirical model, the prediction capabilities are limited to the conditions for which it was developed. In USA, Mechanistic Empirical Pavement Design Guide (MEPDG) has been recently developed to account for increase in truck traffic and minimize premature failure of pavements. Since the new design uses mechanistic approach, it is expected that the design guide can better predict performance of pavements. In addition, mechanistic approach allows use of design guide for different pavement and environmental conditions by calibrating model parameters for …

Finite Element Modeling Of Nondestructive Test Methods Used For Detection Of Delamination In Hot Mix Asphalt Pavements, Dante Mejia Munoz

Open Access Theses & Dissertations

For the simulation of detection of delamination this study focus on three NDT methods: Impact Echo, Impulse Response and Ultrasonic Surface Waves. The was evaluated and then a parametric study was elaborated.

Expert System Design Guide For Lower Classification Roads Over High Pi Clays, Yaqi Wanyan

Open Access Theses & Dissertations

This research was focused on low-volume roads over expansive clayey soils in Texas. In spite of the redundant pavement designs recommended and widely used in Texas for roads in high PI clay areas, these pavements often fail prematurely. This failure occurs primarily because of the highly variable properties of the clayey subgrade throughout the year due to moisture fluctuations. The problematic nature of high PI clays, despite the fact that volumetric changes such as heaving are sometime considered in the design, is of concern since they contribute to roughness and longitudinal shrinkage cracking of the road, and as such the …