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Book ChapterDOI

Effect of Moisture on Fatigue Characteristics of Asphalt Concrete Mixtures

11 Sep 2019-Vol. 48, pp 356-366
TL;DR: In this paper, changes in fatigue characteristics after moisture conditioning were evaluated by conducting four-point beam (4 PB) fatigue tests on dry and moisture conditioned beam specimens, and the results showed that the conditioning reduced both the fatigue life and the initial flexural stiffness of the beam specimens.
Abstract: Moisture in asphalt concrete (AC) pavements does not only cause distresses like potholes, ravelling, etc. but also exacerbates distresses like fatigue and rutting. Moisture susceptibility of AC mixtures is usually characterized using the Modified Lottman Test (AASHTO T283) adopted in Superpave mix design. This test has been observed to provide a good prediction of moisture susceptibility of AC mixtures. However, it does not provide insight on how moisture affects the fatigue characteristics of AC mixtures. Therefore, there is a need for a test procedure that can characterize the effect of moisture on the fatigue behaviour of AC mixtures. In this study, changes in fatigue characteristics after moisture conditioning were evaluating by conducting four-point beam (4 PB) fatigue tests on dry and moisture conditioned beam specimens. For this purpose, specimens of AC mixed with two different types of binders with target air voids of 4 ± 0.5% were prepared. These specimens were subjected to partial vacuum saturation by submerging completely in water and applying vacuum pressure to the system. The fatigue tests were conducted at four different strain amplitudes of 200, 400, 600 and 800 micro-strains. The results were then compared with the fatigue tests results obtained with dry beam specimens. Test results show that the conditioning reduces both the fatigue life and the initial flexural stiffness of the beam specimens. Moreover, it was also observed that the binder type plays a significant role in the degree of saturation.
References
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Book
01 Nov 1992
TL;DR: In this paper, the authors present the theory of pavement design and review the methods developed by several organizations, such as the American Association of State Highway and Transportation Officials (AASHTO), the Asphalt Institute (AI), and the Portland Cement Association (PCA).
Abstract: This is a textbook on the structural analysis and design of highway pavements. It presents the theory of pavement design and reviews the methods developed by several organizations, such as the American Association of State Highway and Transportation Officials (AASHTO), the Asphalt Institute (AI), and the Portland Cement Association (PCA). It can be used for an undergraduate course by skipping the appendices or as an advanced graduate course by including them. The book is organized in 13 chapters. Chapter 1 introduces the historical development of pavement design, the major road tests, the various design factors, and the differences in design concepts among highway pavements, airport pavements, and railroad trackbeds. Chapter 2 discusses stresses and strains in flexible pavements. Chapter 3 presents the KENLAYER computer program, based on Burmister's layered theory, including theoretical developments, program description, comparison with available solutions, and sensitivity analysis on the effect of various factors on pavement responses. Chapter 4 discusses stresses and deflections in rigid pavements due to curling, loading, and friction, as well as the design of dowels and joints. Influence charts for determining stresses and deflections are also presented. Chapter 5 presents the KENSLABS computer program, based on the finite element method, including theoretical developments, program description, comparison with available solutions, and sensitivity analysis. Chapter 6 discusses the concept of equivalent single-wheel and single-axle loads and the prediction of traffic. Chapter 7 describes the material characterization for mechanistic-empirical methods of pavement design including the determination of resilient modulus, fatigue and permanent deformation properties, and the modulus of subgrade reaction. Chapter 8 outlines the subdrainage design including general principles, drainage materials, and design procedures. Chapter 9 discusses pavement performance including distress, serviceability, skid resistance, nondestructive testing, and the evaluation of pavement performance. Chapter 10 illustrates the reliability concept of pavement design in which the variabilities of traffic, material, and geometric parameters are all taken into consideration. A probabilistic procedure, developed by Rosenblueth, is described and two probabilistic computer programs including VESYS for flexible pavements and PMRPD for rigid pavements are discussed. Chapter 11 outlines an idealistic mechanistic method of flexible pavement design and presents in detail the AI method and the AASHTO method, as well as the design of flexible pavement shoulders. Chapter 12 outlines an idealistic mechanistic method of rigid pavement design and presents in detail the PCA method and the AASHTO method. The design of continuous reinforced concrete pavements and rigid pavement shoulders is also included. Chapter 13 outlines the design of overlay on both flexible and rigid pavements including the AASHTO, AI, and PCA procedures. An Author Index and a Subject Index are provided.

2,667 citations

Journal ArticleDOI
TL;DR: The concept of van der surface thermodynamics of (Lewis) Waals was first proposed by as discussed by the authors to account for certain properties of acid-base (AB) Interactions nonideal gases and liquids.
Abstract: The concept of a general attractive interaction between neutral atoms was first proposed by van der Surface Thermodynamics of (Lewis) Waals in 1873, to account for certain properties of Acid-Base (AB) Interactions nonideal gases and liquids.’ Three different but nevThe Young-Dupr6 Equation 933 ertheless related phenomena were subsequently shown to contribute to these “van der Waals” interactions: (1) randomly orienting dipole-dipole (or orientation) inPositive and Negative Interfacial

2,210 citations

Journal ArticleDOI
TL;DR: In this paper, it is shown that the controversy with respect to measurement and interpretation of contact angles is due to the fact that some (or all) of the assumptions made in all energetic approaches are violated when contact angles are measured and processed.

1,281 citations

Journal ArticleDOI
TL;DR: The detrimental effects of water in asphalt mixtures and its manifestation as distresses in asphalt pavements were first recognised in the 1930s and have been studied extensively during the last 35 years as mentioned in this paper.
Abstract: The detrimental effects of water in asphalt mixtures and its manifestation as distresses in asphalt pavements were first recognised in the 1930s and have been studied extensively during the last 35 years. This deterioration process, referred to as moisture damage, is generally defined as the degradation of the mechanical properties of the material due to the presence of moisture in its microstructure. Moisture damage is a complex phenomenon that involves thermodynamic, chemical, physical and mechanical processes. This paper describes the processes by which moisture damage affects asphalt mixtures. A critique of various moisture damage mechanisms is presented, followed by a review of recent work on modes of moisture transport (i.e. water permeability, capillary rise and vapour diffusion) and their relationship to moisture damage. Special attention is given to the characterisation of void structures of asphalt mixtures, which is an important factor that influences moisture transport. Finally, the paper pres...

330 citations

Journal ArticleDOI
TL;DR: In this paper, a refined test method and analysis procedure customized to estimate bitumen surface energy using contact angles measured by the Wilhelmy plate is presented and results are interpreted to study the relationship between contact-angle based surface energies and damage in hot mix asphalt.
Abstract: The ability to quantify adhesion based on surface energies of the bitumen and aggregate components enables selection of compatible materials and quantitative assessment of moisture susceptibility. Reliable surface energy characterization is required in order to implement this technology successfully. One proven method to estimate bitumen surface energy is to calculate it using contact angles measured with various liquids. However, improper selection of probe liquids or interpretation of resulting data can easily mislead users into drawing inaccurate conclusions. This paper presents a refined test method and analysis procedure customized to estimate bitumen surface energy using contact angles measured by the Wilhelmy plate. Results for five neat and three modified bitumen are presented and results are interpreted to study the relationships between contact-angle based surface energies and damage in hot mix asphalt. In a separate study by Bhasin et al. in 2004, surface energy characteristics of bitumen determined using methods described in this paper were combined with surface energies of aggregates to successfully predict moisture susceptibility of mixes.

217 citations