Master of Science / Department of Civil Engineering / Mustaque A. Hossain / Preventive maintenance strategies are applied to pavement to bring it back to appropriate serviceability when it starts to deteriorate soon after construction due to several factors, e.g., traffic loading, deterioration of pavement materials, and climatic effects. In recent years, more and more highway agencies are adopting preventive maintenance strategies and moving away from rehabilitation actions since rehabilitating pavements at near failure is not a cost-effective pavement management technique. A variety of preventive maintenance treatments or thin surface treatments are available to bring pavements back to appropriate serviceability for road users. The Kansas Department of Transportation (KDOT) has adopted several preventive maintenance treatments including thin overlay, ultra-thin bonded asphalt surface (Nova Chip), chip seal, and slurry seal. This thesis discusses the effectiveness of thin surface or preventive maintenance treatments applied in 2007 on 16 highway sections in Kansas. Three types of thin surface treatments, 25-mm Hot-Mix-Asphalt (1” HMA) overlay, ultra-thin bonded asphalt surface (Nova Chip), and chip seal, were examined in this study. These treatments were applied on three types of surface preparation, namely, bare surface, 25-mm surface recycle (1” SR), and 50-mm surface recycle (2” SR). Effectiveness of the thin surface or preventive maintenance treatments for mitigating typical distresses and enhancing pavement performance was evaluated by conducting before-and-after (BAA) comparisons. All data required for this study were extracted from the Pavement Management Information System (PMIS) database of KDOT. It was observed that transverse and fatigue cracking significantly decreased and rutting conditions were improved after the thin surface treatments were applied. Roughness conditions were observed to be better on the highway test sections treated with 25-mm (1”) HMA and Nova Chip, while the effects of chip seals on reducing roughness were not as obvious. Benefit and performance levels of the pavements were observed to rise after the thin surface treatments were applied. The Hamburg Wheel-Tracking Device (HWTD) test was conducted on core samples taken from the highway sections under this study. Laboratory test results showed that most projects exceeded the maximum rut-depth limit (20 mm) specified for 20,000 wheel passes, and the number of wheel passes to failure varied significantly among the projects. Cores from only three projects, two treated with Nova Chip and one with 25-mm (1”) HMA, carried 20,000 wheel passes without exceeding the maximum rut limit of 20 mm (0.8 inch). Pair-wise comparisons or contrasts among the treatments were also performed with the statistical analysis software, SAS. Air void of the HWTD test cores was found to be a significant factor affecting performance of thin surface treatments. The results also revealed that performance was significantly affected by the type of treatment and surface preparation.

Master of Science / Department of Architectural Engineering and Construction Science / Fred L. Hasler / This paper discusses photopic and scotopic vision of the human eye and the implications that could result in the design process of the lighting industry. The incorporation of scotopic vision in lighting effects the perceived illumination in all settings; but these affects and benefits are seen more prevalently at night, as this is when scotopic vision is utilized by the eye the most. The paper will begin with an overview of the eye including discussions of exactly what photopic and scotopic vision are, as well as how the eye works. This will lay a foundation for the paper to help the reader better comprehend and understand the remainder of the content. After the groundwork has been laid, the factors that affect how the eye perceives light will be discussed. These factors include pupil size and color of the light. A discussion of the basis for current lighting industry design and how light levels are measured will follow. Once these topics have been fully explored, there will be a discussion of the changes that could occur in the lighting industry if scotopic vision is taken into account. Increased energy efficiency would result if the scotopic vision is incorporated, resulting from the decrease in needed total lumen output. There have been a few applications that have utilized the effects of the scotopic vision in their design, these cases will be presented. Following the case study discussions, will be a discussion of a survey conducted by myself on the change-out of high pressure sodium (HPS) fixtures to LED fixtures in the downtown Poyntz Avenue area of Manhattan, KS. After all studies have been reviewed, conclusions and correlations among them will be explored. Following this analysis, suggestions will be given to improve the way lighting is designed in the industry.

Master of Science / Department of Architectural Engineering and Construction Science / Sutton F. Stephens / The hazards of seismic activity on building structures require that engineers continually look for new and better methods of resisting seismic forces. Buckling restrained braced frames (BRBF) are a relatively new lateral force resisting system developed to resist highly unpredictable seismic forces in a very predictable way. Generally, structures with a more ductile lateral force resisting system perform better in resisting high seismic forces than systems with more rigid, brittle elements. The BRBF is a more ductile frame choice than special concentrically braced frames (SCBF). The ductility is gained through brace yielding in both compression and tension. The balanced hysteretic curve this produces provides consistent brace behavior under extreme seismic loads. However regular use of the BRB is largely limited to Japan where the brace type was first designed. The wide acceptance of buckling restrained braced frames requires the system to become easily designable, perform predictably, and common to engineers. This report explains the design process to help increase knowledge of the design and background. This report also details a comparison of a BRBF to a SCBF to give familiarity and promote confidence in the system. The design process of the BRBF is described in detail with design calculations of an example frame. The design process is from the AISC Seismic Provisions with the seismic loads calculated according to ASCE 7 equivalent lateral force procedure. The final members sizes of the BRBF and SCBF are compared based on forces and members selected. The results of the parametric study are discussed in detail.

Doctor of Philosophy / Department of Civil Engineering / Mustaque Hossain / The engineers from the Kansas Department of Transportation (KDOT) often have to decide whether or not to accept non-conforming Superpave mixtures during construction. The first part of this study focused on estimating lives of deficient Superpave pavements incorporating nonconforming Superpave mixtures. These criteria were based on the Hamburg Wheel-Tracking Device (HWTD) test results and analysis. The second part of this study focused on developing accelerated mix testing models to considerably reduce test duration. To accomplish the first objective, nine fine-graded Superpave mixes of 12.5-mm nominal maximum aggregate size (NMAS) with asphalt grade PG 64-22 from six administrative districts of KDOT were selected. Specimens were prepared at three different target air void levels @ N[subscript]design gyrations and four target simulated in-place density levels with the Superpave gyratory compactor. Average number of wheel passes to 20-mm rut depth, creep slope, stripping slope, and stripping inflection point in HWTD tests were recorded and then used in the statistical analysis. Results showed that, in general, higher simulated in-place density up to a certain limit of 91% to 93%, results in a higher number of wheel passes until 20-mm rut depth in HWTD tests. A Superpave mixture with very low air voids @ N[subscript]design (2%) level performed very poorly in the HWTD test. HWTD tests were also performed on six 12.5-mm NMAS mixtures with air voids @ N[subscript]design of 4% for six projects, simulated in-place density of 93%, two temperature levels and five load levels with binder grades of PG 64-22, PG 64-28, and PG 70-22. Field cores of 150-mm in diameter from three projects in three KDOT districts with 12.5-mm NMAS and asphalt grade of PG 64-22 were also obtained and tested in HWTD for model evaluation. HWTD test results indicated as expected. Statistical analysis was performed and accelerated mix testing models were developed to determine the effect of increased temperature and load on the duration of the HWTD test. Good consistency between predicted and observed test results was obtained when higher temperature and standard load level were used. Test duration of the HWTD can thus be reduced to two hours or less using accelerated mix testing (statistical) models.

Doctor of Philosophy / Department of Civil Engineering / Mustaque Hossain / A Superpave asphalt mixture with 4.75-mm nominal maximum aggregate size (NMAS) is a promising, low-cost pavement preservation treatment for agencies such as the Kansas Department of Transportation (KDOT). The objective of this research study is to develop an optimized 4.75-mm NMAS Superpave mixture in Kansas. In addition, the study evaluated the residual tack coat application rate for the 4.75-mm NMAS mix overlay. Two, hot-in-place recycling (HIPR) projects in Kansas, on US-160 and K-25, were overlaid with a 15- to 19-mm thick layer of 4.75-mm NMAS Superpave mixture in 2007. The field tack coat application rate was measured during construction. Cores were collected from each test section for Hamburg wheel tracking device (HWTD) and laboratory bond tests performed after construction and after one year in service. Test results showed no significant effect of the tack coat application rate on the rutting performance of rehabilitated pavements. The number of wheel passes to rutting failure observed during the HWTD test was dependent on the aggregate source as well as on in-place density of the cores. Laboratory pull-off tests showed that most cores were fully bonded at the interface of the 4.75-mm NMAS overlay and the HIPR layer, regardless of the tack application rate. The failure mode during pull-off tests at the HMA interface was highly dependent on the aggregate source and mix design of the existing layer material. This study also confirmed that overlay construction with a high tack coat application rate may result in bond failure at the HMA interface. Twelve different 4.75-mm NMAS mix designs were developed using materials from the aforementioned but two binder grades and three different percentages of natural (river) sand. Laboratory performance tests were conducted to assess mixture performance. Results show that rutting and moisture damage potential in the laboratory depend on aggregate type irrespective of binder grade. Anti-stripping agent affects moisture sensitivity test results. Fatigue performance is significantly influenced by river sand content and binder grade. Finally, an optimized 4.75-mm NMAS mixture design was developed and verified based on statistical analysis of performance data.

Doctor of Philosophy / Department of Biological & Agricultural Engineering / James K. Koelliker / Small reservoirs catch and store water for long periods and they decrease streamflow and increase ground-water recharge. A field monitoring program provided the measured water depth for four years in several reservoirs in the Republican River Basin where there are concerns about their aggregate effects in the basin. The daily water budget operation for one reservoir was developed. Daily seepage rates were estimated by using precipitation, inflow and evaporation which was assumed equal to grass reference evapotranspiration (ET0), that average 120 to 150 cm/yr, along with the measured stage-storage and stage-surface area relationships. Two computer simulation modules, written in FORTRAN 95, were developed to estimate 1) overflow and gross seepage and 2) potential for ground-water recharge underneath the reservoir. Required daily input data are precipitation, ET0, and inflow from the watershed area. Required reservoir site characteristics include stage-storage and stage-surface area relationships, a standard seepage rate (S0) at 14 different levels in the reservoir, soil-water and plant-growth characteristics and a monthly crop-residue factor. The gross seepage module calculates water depth that determines daily overflow, the water-surface area for evaporation and the head of water on the 14 levels to cause seepage losses. If a level is not inundated, seepage is zero. If a level is inundated less than 0.3-m, S0 is used. When the water head (hL) on a level exceeds 0.3 m, the seepage rate (SL) is increased by, SL = S0 * (hL/0.3)0.25. This relationship was chosen after testing several exponent values between 0 and 1. The modules were calibrated on one reservoir and verified on two others in northwestern Kansas. Results showed runoff from the watersheds averaged about 1.2 to 1.6 cm/yr from the average annual precipitation of 46 to 62 cm. The three reservoirs reduced streamflow at the reservoir site by 74 to 97%, but 90 to 95% of the retained runoff was calculated to contribute to ground-water recharge. Several sensitivity analyses for model inputs were done. Results showed that, the ratio of the average annual inflow volume from the watershed area to the reservoir storage volume was the most sensitive input variable tested.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Daniel V. Swenson / The objective of the thesis is to provide a fully coupled thermo-hydro-mechanical (THM) tool, T2STR, which enables quantitative understanding and prediction of thermal as well as mechanical effects on flow in the porous media under multiphase conditions. This is achieved by incorporating a finite element based hydro-thermo-mechanical stress capability into the well-established IFDM (Integrated Finite Difference Method) based flow simulation code TOUGH2. TOUGH2 is a program for calculation of multi-phase, multi-component, non-isothermal flow in porous media. It implements several equation of state modules to represent different fluid mixtures. The dual mesh technique is natural for combining both discretization methods and is used innovatively and effectively. A generalized approach is developed to accommodate the switching of variables implemented in TOUGH2 to adapt the phase changes. The forward coupling is achieved by using the thermal, hydrostatic, and poroelastic effects in the stress calculations. The backward coupling includes the effect of strain on the fluid flow. T2STR also allows the user to study the variation in porosity, permeability and capillary pressure as function of mean effective stress in the porous media. Multiple materials can be used to model the reservoir in T2STR, parallel to the implementation in TOUGH2. T2STR is implemented to carry out as a fully coupled, one way coupled (only deformation as function of hydro-thermal effects), or original TOUGH2 implementation. It provides the ability to switch on and off the thermal and/or poroelastic effects. T2STR is developed to model the fractured porous media using discrete fractures. The modeling of fractured porous media is limited to a staggered coupling approach. The fluid parameters like permeability, porosity are modified based on the stresses and/or aperture changes due to deformation. A set of verification problems, used to validate the code and display the capabilities of the code, are discussed. A graphical user interface is designed to pre-process the necessary data. Macros are developed for excel and Tecplot to post-process the results for easy visualization.