ASU Electronic Theses and Dissertations

Nighttime visibility of pavement markings is provided by glass beads embedded into the striping surface. The glass beads take light from the vehicle headlamps and reflect it back to the driver. This phenomenon is known as retroreflection. Literature suggests that the amount of the bead embedded into the striping surface has a profound impact on the intensity of the retroreflected light. In order to gain insight into how the glass beads provide retroreflection, an experiment was carried out to produce paint stripes with glass beads and measure the retroreflection. Samples were created at various application rates and embedment depths, in an attempt to verify the optimal embedment and observe the effect of application rate on retroreflection. The experiment was conducted using large, airport quality beads and small, road quality beads. Image analysis was used to calculate the degree to which beads were embedded and in an attempt to quantify bead distribution on the stripe surface. The results from the large beads showed that retroreflection was maximized when the beads were embedded approximately seventy percent by bead volume. The results also showed that as the application rate increased, the retroreflection increased, up to a point and then decreased. A model was developed to estimate the retroreflectivity given the amount of beads, bead spacing, and distribution of bead embedment. Results from the small beads were less conclusive, but did demonstrate that the larger beads are better at providing retroreflection. Avenues for future work in this area were identified as the experiment was conducted.

This study investigates the mastic level structure of asphalt concrete containing RAP materials. Locally sourced RAP material was screened and sieved to separate the coated fines (passing #200) from the remaining sizes. These binder coated fines were mixed with virgin filler at proportions commensurate with 0%, 10%, 30%, 50% and 100% RAP dosage levels. Mastics were prepared with these blended fillers and a PG 64-22 binder at a filler content of 27% by volume. Rheological experiments were conducted on the resulting composites as well as the constituents, virgin binder, solvent extracted RAP binder. The results from the dynamic modulus experiments showed an expected increase in stiffness with increase in dosage levels. These results were used to model the hypothesized structure of the composite. The study presented discusses the different micromechanical models employed, their applicability and suitability to correctly predict the blended mastic composite. The percentage of blending between virgin and RAP binder estimated using Herve and Zaoui model decreased with increase in RAP content.

Pavement preservation is the practice of selecting and applying maintenance activities in order to extend pavement life, enhance performance, and ensure cost effectiveness. Pavement preservation methods should be applied before pavements display significant amounts of environmental distress. The long-term effectiveness of different pavement preservation techniques can be measured in terms of life extension, relative benefit, and benefit-cost ratio. Optimal timing of pavement preservation means that the given maintenance treatment is applied so that it will extend the life of the roadway for the longest possible period with the minimum cost. This document examines the effectiveness of chip seal treatment in four climatic zones in the United States. The Long-Term Pavement Performance database was used to extract roughness and traffic data, as well as the maintenance and rehabilitation histories of treated and untreated sections. The sections were categorized into smooth, medium, and rough pavements, based upon initial condition as indicated by the International Roughness Index. Pavement performance of treated and untreated sections was collectively modeled using exponential regression analysis. Effectiveness was evaluated in terms of life extension, relative benefit, and benefit-cost ratio. The results of the study verified the assumption that treated sections performed better than untreated sections. The results also showed that the life extension, relative benefit, and benefit cost ratio are highest for sections whose initial condition is smooth at the time of chip seal treatment. These same measures of effectiveness are lowest for pavements whose condition is rough at the time of treatment. Chip seal treatment effectiveness showed no correlation to climatic conditions or to traffic levels.

The built environment is responsible for a significant portion of global waste generation.

Construction and demolition (C&D) waste requires significant landfill areas and costs

billions of dollars. New business models that reduce this waste may prove to be financially

beneficial and generally more sustainable. One such model is referred to as the “Circular

Economy” (CE), which promotes the efficient use of materials to minimize waste

generation and raw material consumption. CE is achieved by maximizing the life of

materials and components and by reclaiming the typically wasted value at the end of their

life. This thesis identifies the potential opportunities for using CE in the built environment.

It first calculates the magnitude of C&D waste and its main streams, highlights the top

C&D materials based on weight and value using data from various regions, identifies the

top C&D materials’ current recycling and reuse rates, and finally estimates a potential

financial benefit of $3.7 billion from redirecting C&D waste using the CE concept in the

United States.