Guy Ramond

Bio: Guy Ramond is an academic researcher. The author has an hindex of 3, co-authored 3 publications receiving 180 citations.

A mathematical-based master-curve construction method applied to complex modulus of bituminous materials

Abstract: This paper gives a mathematical-based procedure in order to construct master-curves from complex-modulus measurements. The method is based on the Kramers-Kronig relations linking modulus and phase angle of a complex function. Three pure bitumens, one polymer-modified-binder and two mixtures are chosen to validate the possible use of this methodology and apply it. Assumptions which are needed to apply this procedure, are verified on complex-modulus data measured from these materials. Hence, master-curves can be built without introducing error from manual adjustement. The method seems to be suitable for binders and mixtures as soon as their behaviour is in agreement with the time-temperature equivalency principle. In conclusion, some interpretations of the WLF constants are given.

Relationships between composition, structure, and properties of road asphalts: state of research at the french public works central laboratory

Abstract: Reviewed is the past and ongoing research conducted at France's Laboratoire Central des Ponts et Chaussees (LCPC) (Public Works Central Laboratory) in the area of asphalt cements. The investigations cover the development of methods for characterizing the physicochemical and rheological properties of such materials, and the establishment of relationships between their composition, colloidal structure, and practical properties. For physicochemical characterization, the research makes use of such techniques as high-pressure liquid chromatography, gel permeation chromatography (GPC), and differential scanning calorimetry. The rheological behavior of materials is studied by the peeling technique, viscoelastisimetry, and viscosimetry on thin films (with specially designed apparatus). Theoretical studies have led to the proposal of a new rheological behavior model better suited to experimental results than conventional models, characterized by its analogy with the laws of chemical kinetics, and allowing the calculation of a structural parameter as well as a parameter dependent on energy per unit volume dissipated and having activation energy characteristics. The foregoing assessment brings out the effectiveness of the facilities set up by the LCPC, and it is important to note that the new characterization methods indicate that asphalt cements with the same specifications have substantially different physicochemical compositions and rheological behaviors. Among the most important results, it is demonstrated that GPC makes it possible to characterize the equilibrium of the colloidal structure of asphalt cement and to obtain information on the ability of asphaltenes to interact to form a more or less developed network responsible for the gel character of the rheological behavior noted. It is also demonstrated that information obtained by GPC on the interaction of asphaltene micelles is closely correlated with certain observed characteristics of rheological behavior.

Chapter 18 Relationships Among Composition, Structure, and Properties of Road Asphalts

Abstract: Publisher Summary This chapter outlines the facilities acquired by France's Laboratoire Central des Ponts et Chaussees (LCPC) road research laboratories in the area of physicochemical characterization and investigations on the rheological behavior of materials (peeling, viscoelastisimetry, and viscosity of ultra-thin films). The chapter also discusses the experimental relationships between composition, structure, and properties and determines the evolution of these relationships after mixing and weathering. It describes the development of methods for characterizing the physicochemical and rheological properties of such materials, and the establishment of relationships between their composition, colloidal structure, and practical properties. The new characterization methods show that asphalt cements with the same specifications have substantially different chemical compositions and rheological behaviors. Emphasis should now be placed on the practical application of physicochemical methods such as gel permeation chromatography (GPC) and on the experimental relationships between the composition, structure, and properties of these materials.

Polymer-Modified Asphalt Cements Used in the Road Construction Industry: Basic Principles

Abstract: Modified binders—obtained by adding thermoplastic macromolecular systems of plastomers or elastomers to traditional pure asphalt cements for road construction—have existed for more than 20 years. These products are still poorly understood scientifically. Significant research must be undertaken to better understand binder relationships between composition, structure, and properties, and the relationships between hot mix performance (rutting, fatigue, thermal cracking) and the characteristics of the modified binders as measured in the laboratory. The current state of knowledge regarding these issues is presented along with a discussion of the basic principles of bitumen-polymer compatibility, the mechanism for modification, and the effect of the components on the properties of the modified binders. Several specific problems related to the use of these products are presented.