Engineering Commons^™

Impact Of Clay Contamination On Rutting Performance Of Asphalt Mixes, Sharmila Afsha

Open Access Theses & Dissertations

Sustainability of asphalt mixtures can be improved by using natural sands. They can enhance workability and lower the amounts required for asphalt binder and manufactured fine aggregate of mixes. However, one of the primary concerns with incorporating natural sands in a mixture is clay contamination. Harmful clays are chemically active particles that swell when exposed to moisture and reduce the bond between aggregate and asphalt binder. As a result, this study explores the effect of clay contamination on the rutting and moisture susceptibility of asphalt mixes. Twenty-one clay combinations of material passing the 0.075 mm (#200) sieve were selected utilizing …

Harmonizing Asphalt Mix Selection With Pavement Structural Design, Mahdi Saghafi

Open Access Theses & Dissertations

The state-of-the-practice in asphalt concrete (AC) mix design and pavement structural design are based on two divergent concepts. The laboratory tests that are used for mix design, especially under the balanced mix design concept, are pragmatically accelerated surrogate tests developed to ensure the stability or ranking of mixes. Pavement structural design methods, being empirical or mechanistic, ignore these laboratory test results, in favor of other mechanical parameters. As such, the selection of the type of mix to be placed on a project is based on the local experience, and a set of consensus limits, rather than the demand of the …

New Generation Of Performance-Engineered Asphalt Mixtures Based On Balanced Mix Design Concept, Victor Manuel Garcia

Open Access Theses & Dissertations

Asphalt mixtures must ideally exhibit long-lasting durability and stability to perform wellin the field. However, improving the stability and durability of asphalt mixtures has become a major concern. Given that available design approaches rely mainly on stringent volumetric criteria for asphalt mixtures, design approaches and specifications that incorporate performance tests are needed to follow a performance-engineered mix design (PEMD) process, especially with the introduction of the balanced mix design (BMD) concept

This Dissertation study presents a comprehensive investigation of a feasible designapproach that can be implemented to develop PEMD specifications and produce BMD mixtures. An experimental evaluation of different mix …

Influence Of Mix Design Parameters On Performance Of Balanced Asphalt Mixtures, Luiza Helena Barros

Open Access Theses & Dissertations

With the popularity of the Balanced Mix Design (BMD) concept, the need for performance tests that can reliably evaluate the cracking and rutting potentials of asphalt concrete (AC) mixes has become more critical. A great deal of effort has been focused on incorporating test methods that can potentially improve the current AC mix-design processes and consequently screen underperforming AC mixes. However, the influence of mix design parameters on the performanceof BMD mixes that provide pavement engineers and designers with thorough guidelines and a reliable and consistent test protocol has not been extensively documented.

This Thesis presents an experimental evaluation of …

Integrated Finite Element Analysis Program To Evaluate Pavement Performance And Predict Non-Destructive Testing Response, Cesar Tirado

Open Access Theses & Dissertations

The response of a pavement system under wheel loading has been a subject of research for many decades. Several models have been developed to predict pavement performance based on layer deformation and fatigue cracking. Among them stand out computer programs based on linear elasto-static layered systems and viscoelastic-plastic models; however, newer or more advanced constitutive models cannot be rigorously incorporated into them. In contrast, finite element techniques allow incorporation of nonlinear and viscoelastic-plastic behavior of the pavement materials but licensing of software and the need to train personnel greatly limits its use by highway agencies. A mechanistic-empirical (M-E) approach for …