Master of Science / Department of Architectural Engineering and Construction Science / Kimberly Waggle Kramer / This document addresses East Africa's need for safe, sustainable, and affordable housing and promotes use of bamboo as a structural material by providing adequate information and resources to evaluate the strength of bamboo. East African housing is a leading issue for the region because of the population growth, specifically in urban areas where housing resources and infrastructure cannot match the population growth. The solution may be bamboo housing as an alternative to urban slums. The bamboo species Oxytenanthera abyssinica is available throughout East Africa region and has been accepted and implemented in traditional housing throughout the region. This document references the resources provided by the International Code Council (ICC), International Organization for Standardizations (ISO), and International Network for Bamboo and Rattan (INBAR) for the use of bamboo as a structural material in buildings. This paper also discusses the mechanical strength of bamboo, and the structural behavior of bamboo in buildings. In addition, bamboo construction shows the tools, connections, and preservatives used in the field. The design example, using Oxytenanthera abyssinica, provides the traditional layout and materials for an Amhara house, and calculations show the practicality of bamboo in structural design. This document has led to recommendations for engineers and the bamboo industry, including the development of a codebook for bamboo design, promoting bamboo farms and plantations, creating a uniform connection, and increasing bamboo's service life. From research, bamboo is in need of further development before being considered a viable structural material to provide for commercial use but would suffice for the housing shortage in East Africa.

Master of Science / Department of Architectural Engineering / Kimberly Waggle Kramer / Reinforced concrete slabs are one of the most common components in modern building construction. Reinforced concrete slabs with plastic voids slabs are a new and innovative type of structural, concrete slab system developed to allow for lighter self-weight of the structure while maintaining similar load carrying capacity of a solid slab. Plastic voided slabs are capable of reducing the amount of concrete necessary to construct a building by 30 percent or more. This reduction can be beneficial in terms of financial savings as well as building performance. This report examines a two-way, reinforced concrete slab with plastic voids construction in comparison to traditional flat plate reinforced concrete slab construction. The design process for plastic voided slabs is directly compared with traditional two-way flat plate reinforced concrete slabs through a design comparison of typical bays of 20’ by 20’ (6m by 6m), 25’ by 25’ (7.6m by 7.6m), 30’ by 30’ (9m by 9m) and 35’ by 35’ (10.7m by 10.7m). The traditional slab design process follows the ACI 318-11 Building Code Requirements for Structural Concrete chapter 13 Direct Design Method, while the plastic voided slab design process is modified from the BubbleDeck Design Guide for compliance with BCA using AS3600 and EC2. Sizes of traditional slab bays are compared to sizes of plastic voided slab bays. Results of the comparison study are presented.

Master of Science / Department of Architectural Engineering and Construction Science / Kimberly Waggle Kramer and Bill Zhang / Concrete masonry units are a common method of construction in the world. Since the masonry units can be constructed with ease. Fifty billion water bottles are consumed every year. Lack of waste management and recycling in third world countries has come to the attention of many organizations. The use of plastic bottles in construction materials has been around for the past twenty years, but with little focus on using full plastic bottles in the materials. The Engineers Without Borders student group on the campus at Kansas State University have found a way to utilize the full 500-mL plastic bottle in the creation of concrete walls. The bottles laid horizontally with concrete on both sides and as mortar between the bottles was used. These bottles create large voids in the wall decreasing the compressive strength of the wall. This thesis presents the results of a study conducted to determine the compressive strength of concrete masonry units with plastic bottle cores. The plastic bottles were used to create the center voids in the masonry units. Concrete was placed around the bottles to encase them in the masonry units. The study utilized 500-mL plastic bottles from five different water companies placed inside masonry units of 7.87-inch wide by 8.26-inch high by 15.75-inch long (200-mm wide by 210-mm high by 400-mm long) in size and analyzed the resultant compressive strength. The testing for compressive strength was determined according to the ASTM C140 standard. Results from this study were deemed reasonable due to the testing of concrete cylinders as a control compressive strength. Determination of the compressive strength of the concrete masonry units allows for further study to continue in concrete masonry units with plastic bottle cores to determine if they are viable in third world countries.

Doctor of Philosophy / Department of Civil Engineering / Kyle A. Riding / Finely ground glass has the potential for pozzolanic reactivity and can serve as a supplementary cementitious material (SCM). Glass reaction kinetics depends on both temperature and glass composition. Uniform composition, amorphous nature, and high silica content of glass make ground glass an ideal material for studying the effects of glass type and particle size on reactivity at different temperature. This study focuses on how three narrow size ranges of clear and green glass cullet, 63–75 [mu]m, 25–38 [mu]m, and smaller than 25 [mu]m, as well as combination of glass types and particle sizes affects the microstructure and performance properties of cementitious systems containing glass cullet as a SCM. Isothermal calorimetry, chemical shrinkage, thermogravimetric analysis (TGA), quantitative analysis of X-ray diffraction (XRD), and analysis of scanning electron microscope (SEM) images in backscattered (BS) mode were used to quantify the cement reaction kinetics and microstructure. Additionally, compressive strength and water sorptivity experiments were performed on mortar samples to correlate reactivity of cementitious materials containing glass to the performance of cementitious mixtures. A recently-developed modeling platform called “[mu]ic the model” was used to simulated pozzolanic reactivity of single type and fraction size and combined types and particle sizes of finely ground glass. Results showed that ground glass exhibits pozzolanic properties, especially when particles of clear and green glass below 25 [mu]m and their combination were used at elevated temperatures, reflecting that glass cullet is a temperature-sensitive SCM. Moreover, glass composition was seen to have a large impact on reactivity. In this study, green glass showed higher reactivity than clear glass. Results also revealed that the simultaneous effect of sizes and types of glass cullet (surface area) on the degree of hydration of glass particles can be accounted for through a linear addition, reflecting that the surface area would significantly affect glass cullet reactivity and that the effects of SCM material interaction on reaction kinetics were minimal. However, mechanical properties of cementitious systems containing combined glass types and sizes behaved differently, as they followed the weaker portion of the two particles. This behavior was attributed to the pores sizes, distruibution, and connectiity. Simulations of combined glass types and sizes showed that more work on microstructural models is needed to properly model the reactivity of mixed glass particle systems.

Master of Science / Department of Civil Engineering / Robert J. Peterman / Epoxy polymer overlays have been used for decades on existing bridge decks to protect the deck and extend its service life. The polymer overlay’s ability to seal a bridge deck is now being specified for new construction. Questions exist about the amount of drying time needed to achieve an acceptable concrete moisture content to ensure an adequate bond to the polymer overlay. Current Kansas Department of Transportation (KDOT) specifications for new bridge decks call a 14 day wet curing period followed by 21 days of drying (Kansas DOT, 2007) If not enough drying is provided, the moisture within the concrete can form water vapor pressure at the overlay interface and induce delamination. If too much drying time is provided projects are delayed, which can increase the total project cost or even delay overlay placement until the next spring. A testing procedure was developed to simulate a bridge deck in order to test the concrete moisture content and bonding strength of the overlay. Concrete slabs were cast to test typical concrete and curing conditions for a new bridge deck. Three concrete mixtures were tested to see what effect the water –cement ratio and the addition of fly ash might have on the overlay bond strength. Wet curing occurred at 3 different temperatures (40°F, 73°F, and 100°F) to see if temperature played a part in the bond strength as well. The concrete was then allowed to dry for 3, 7, 14, or 21 days. Five epoxy-polymer overlay systems that had been preapproved by KDOT were each used in conjunction with the previously mentioned concrete and curing conditions. After, the slabs were setup to perform pull-off tests to test the tensile rupture strength. The concrete slabs with the different epoxy overlays were heated to 122-125°F to replicate summer bridge deck temperatures. Half of the pull-off tests were performed when the slabs were heated and half were performed once the slabs had cooled back down to 73°±5°F. Results from the pull-off tests as well as results from a moisture meter taken on the concrete prior to the overlay placement were compared and analyzed. Testing conditions were compared with each other to see which had a larger effect on the epoxy polymer overlay’s bond strength.

Master of Science / Department of Civil Engineering / Dunja Peric / Piles have been used for many years in civil infrastructure as foundations for buildings, bridges, and retaining walls. Energy piles are thermo-active foundation systems that use geothermal energy for heating and cooling of buildings. Ground source heat is a very attractive, economical, efficient and sustainable alternative to current heating practices. Unlike the air temperature, the temperature below the Earth’s surface remains relatively constant throughout the year, somewhere between 10oC to 15oC below a depth of 6 m to 9 m (Kelly, 2011). This provides an opportunity for construction of thermo-active foundation systems with embedded geothermal loops. The main purpose of such thermo-active system is to transfer deep ground heat to a building through the fluid circulating within the geothermal loop. It is because these thermo-active foundation systems enable heat exchange between the deep ground and the building that is called the heat exchanger pile (HEP). The thermal energy supplied by a HEP can then supplement air-pump-based heating/cooling system. Although heat exchanger piles have been successfully implemented in Europe and Asia, their usage in U.S. remains uncommon. One reason for this might be currently limited understanding of the associated soil-structure interaction, thus unfavorably affecting the design procedures. To this end, a study was undertaken to investigate the predictive capabilities of computational models and to gain a better understanding of the load-transfer mechanisms of energy piles. Thus, coupled thermo-hydro-mechanical computational modeling of a single actual end bearing HEP was carried out for different loading scenarios including thermal and mechanical loads by using the finite element code ABAQUS/Standard 6.13-2. The results of the analyses of the heat exchanger pile with two different types of layered soil profile are presented: isotropic and anisotropic. The computational model was validated and verified successfully against field test results for all considered loading scenarios. Additional analyses were performed to gain a deeper insight into the effects of soil layering and on the behavior of energy piles. It was found that changes in the soil stiffness affected primarily the head displacement and vertical stresses and strains in the pile.

Master of Science / Department of Civil Engineering / Hani G. Melhem / Fiber Reinforced Polymer (FRP) is a relatively new material used in the field of civil engineering. FRP is composed of fibers, usually carbon or glass, bonded together using a polymer adhesive and formed into the desired structural shape. Recently, FRP deck panels have been viewed as an attractive alternative to concrete decks when replacing deteriorated bridges. The main advantages of an FRP deck are its weight (roughly 75% lighter than concrete), its high strength-to-weight ratio, and its resistance to deterioration. In bridge design, AASHTO provides load distributions to be used when determining how much load a longitudinal beam supporting a bridge deck should be designed to hold. Depending on the deck material along with other variables, a different design distribution will be used. Since FRP is a relatively new material used for bridge design, there are no provisions in the AASHTO code that provides a load distribution when designing beams supporting an FRP deck. FRP deck panels, measuring 6 ft x 8.5’, were loaded and analyzed at KSU over the past 4 years. The research conducted provides insight towards a conservative load distribution to assist engineers in future bridge designs with FRP decks. Two separate test periods produced data for this thesis. For the first test period, throughout the year of 2007, a continuous FRP panel was set up at the Civil Infrastructure Systems Laboratory at Kansas State University. This continuous panel measured 8.5 ft by 6 ft x 6 in. thick and was supported by 4 Grade A572 HP 10 x 42 steel beams. The beam spacing’s, along the 8.5 ft direction, were 2.5 ft-3.5 ft-2.5 ft. Stain gauges were mounted at mid-span of each beam to monitor the amount of load each beam was taking under a certain load. Linear variable distribution transformers (LVDT) were mounted at mid-span of each beam to measure deflection. Loads were placed at the center of the panel, with reference to the 6 ft direction and at several locations along the 8.5 ft direction. Strain and deflection readings were taken in order to determine the amount of load each beam resisted for each load location. The second period of testing started in the fall of 2010 and extended into January of 2011. This consisted of a simple-span/cantilever test set-up. The test set-up consisted of, in the 8.5 ft direction, a simply supported span of 6 ft with a 2.5 ft cantilever on one side. As done previously both beams had strain gauges along with LVDTs mounted at mid-span. There were also strain gauges were installed spaced at 1.5ft increments along one beam in order to analyze the beam behavior under certain loads. Loads were once again applied in the center of the 6 ft direction and strain and deflection readings were taken at several load locations along the 8.5 ft direction. The data was analyzed after all testing was completed. The readings from the strain gauges mounted in 1.5 ft increments along the steel beam on one side of the simple span test set-up were used to produce moment curves for the steel beam at various load locations. These moment curves were analyzed to determine how much of the panel was effectively acting on the beam when loads were placed at various distances away from the beam. Using these “effective lengths,” along with the strain taken from the mid-span of each beam, the loads each beam was resisting for different load locations were determined for both the continuously supported panel and the simply supported/cantilever panel data. Using these loads, conservative design factors were determined for FRP panels. These factors are S/5.05 for the simply supported panel and S/4.4 for the continuous panel, where “S” is the support beam spacing. Deflections measurements were used to validate the results. Percent errors, based on experimental and theoretical deflections, were found to be in the range of 10 percent to 40 percent depending on the load locations for the results in this thesis.

Master of Science / Department of Civil Engineering / Dunja Peric / The main objective of this study was to experimentally investigate the Mohr-Coulomb strength parameters of masonry sand mixed with varying amounts of water and lignin. Lignin is a plant-derived biomass, which is a co-product of bio-fuel production. It exhibits binding qualities when mixed with water thus making it an ideal candidate for sustainable non-traditional sand stabilization. An experimental program was devised and carried out to quantify the compaction and early age stress-strain and dilatancy responses of sand-lignin mixes. The program included sieve analysis, Atterberg limit tests, standard Proctor tests, and direct shear tests. The experimental results were used to find the cohesion and the angle of internal friction of the tested material, therefore determining the influence of the amount of lignin and water on the strength of the samples. An extensive data analysis was subsequently completed to gain deeper understanding of the underlying strength gain mechanism. It was found that the normalized cohesion benefit due to lignin is controlled by two variables; water to lignin ratio and void ratio. The lignin and water create a paste, which provides particle bonding at the contacts of sand particles, thus increasing the stress-bearing cross sectional area. Increase in the portion of cross-sectional area occupied by water and lignin normalized by gravimetric lignin content, increases the normalized cohesion up to a point, while the cohesion per gravimetric lignin content decreases with the increasing area ratio. This in turn indicates that cohesion increases only up to 6% of lignin, beyond which it starts to decrease due to the presence of too much fine material within the pores. The presence of lignin in the pores consistently decreases the angle of internal friction. However, for all configurations with lignin tested herein, cohesion was larger than for dry sand, thus indicating strength benefits at low confining pressures or at normal stresses below the so-called limiting normal stress.

Master of Science / Department of Civil Engineering / Robert Peterman / A flowable hybrid concrete mix with a spread of 17 to 20 inches was created with a superplasticizer to be used in post-tension haunch-slab (PTHS) bridges where rebar congestion is heaviest. The mix would allow for proper concrete consolidation. A conventional concrete mix with a slump of three to four inches was also created to be placed on top of the hybrid mix. The conventional mix would be used to create a sloping surface on the top of the concrete. The two mixes could be combined in the PTHS bridge deck and act as one monolithic specimen. Standard concrete tests such as compressive strength, tensile strength, modulus of elasticity, permeability, freeze/thaw resistance, and coefficient of thermal expansion were determined for the mixes and compared. Core blocks were cast using both mixes and composite cores were drilled. The cores were tested and their composite split-tensile strengths were compared to the split-tensile strengths of cylinders made from the respective mixes. A third concrete mix was made by increasing the superplasticizer dosage in the hybrid concrete mix to create a self-consolidating concrete (SCC) mix with a 24-inch spread. The SCC mix was created as a worst-case scenario and used in the determination of shear friction. Eighty-four push-off shear friction specimens were cast using the SCC mix. Joint conditions for the specimens included uncracked, pre-cracked, and cold-joints. Uncracked and pre-cracked specimens used both epoxy- and non-epoxy-coated shear stirrups. Cold-joint specimens used both the SCC mix and the conventional concrete mix. Joint-conditions of the cold-joint specimens included a one-hour cast time, a seven-day joint with a clean shear interface, and a seven-day joint with an oiled shear interface. The shear friction specimens were tested using a pure shear method and their results were compared to the current American Concrete Institute code equation.

Master of Science / Department of Civil Engineering / Sunanda Dissanayake / In order to improve safety of the overall surface transportation system, each of the critical areas needs to be addressed separately with more focused attention. Statistics clearly show that large-truck crashes contribute significantly to an increased percentage of high-severity crashes. It is therefore important for the highway safety community to identify characteristics and contributory causes related to large-truck crashes. During the first phase of this study, fatal crash data from the Fatality Analysis Reporting System (FARS) database were studied to achieve that objective. In this second phase, truck-crashes of all severity levels were analyzed with the intention of understanding characteristics and contributory causes, and identifying factors contributing to increased severity of truck-crashes, which could not be achieved by analyzing fatal crashes alone. Various statistical methodologies such as cross-classification analysis and severity models were developed using Kansas crash data. Various driver-, road-, environment- and vehicle- related characteristics were identified and contributory causes were analyzed. From the cross-classification analysis, severity of truck-crashes was found to be related with variables such as road surface (type, character and condition), accident class, collision type, driver- and environment-related contributory causes, traffic-control type, truck-maneuver, crash location, speed limit, light and weather conditions, time of day, functional class, lane class, and Average Annual Daily Traffic (AADT). Other variables such as age of truck driver, day of the week, gender of truck-driver, pedestrian- and truck-related contributory causes were found to have no relationship with crash severity of large trucks. Furthermore, driver-related contributory causes were found to be more common than any other type of contributory cause for the occurrence of truck-crashes. Failing to give time and attention, being too fast for existing conditions, and failing to yield right of way were the most dominant truck-driver-related contributory causes, among many others. Through the severity modeling, factors such as truck-driver-related contributory cause, accident class, manner of collision, truck-driver under the influence of alcohol, truck maneuver, traffic control device, surface condition, truck-driver being too fast for existing conditions, truck-driver being trapped, damage to the truck, light conditions, etc. were found to be significantly related with increased severity of truck-crashes. Truck-driver being trapped had the highest odds of contributing to a more severe crash with a value of 82.81 followed by the collision resulting in damage to the truck, which had 3.05 times higher odds of increasing the severity of truck-crashes. Truck-driver under the influence of alcohol had 2.66 times higher odds of contributing to a more severe crash. Besides traditional practices like providing adequate traffic signs, ensuring proper lane markings, provision of rumble strips and elevated medians, use of technology to develop and implement intelligent countermeasures were recommended. These include Automated Truck Rollover Warning System to mitigate truck-crashes involving rollovers, Lane Drift Warning Systems (LDWS) to prevent run-off-road collisions, Speed Limiters (SLs) to control the speed of the truck, connecting vehicle technologies like Vehicle-to-Vehicle (V2V) integration system to prevent head-on collisions etc., among many others. Proper development and implementation of these countermeasures in a cost effective manner will help mitigate the number and severity of truck-crashes, thereby improving the overall safety of the transportation system.