Analysis of physicochemical Interaction between the components of asphalt mixtures with rubber

Elvira Joana Joana Ferreira Ferreira Peralta, Iowa State University

Abstract

Earth is full of resources; in reality there is no waste, what sometimes happens is a lack of knowledge and ability to transform that waste into valuable materials. The present work can be a good example of how waste can be transformed into a needed construction material.

Asphalt is the most common binder material in road construction. However, the need for more durable and safer road pavements requires a better understanding of asphalt concerning its aging mechanisms, and how its characteristics can be improved by the addition of polymers. Despite asphalt modified with crumb rubber from used tires has been applied with great success all over the world since the sixties, the phenomena of interaction between the asphalt and rubber are not yet fully understood.

The bio-oil produced by fast pyrolysis of organic materials is commercially available for over a decade. This material has been mainly used as fuel, in the same way as petroleum. However, its properties are similar to those of asphalt and it may prove to be an excellent substitute.

In this thesis the mechanisms of aging of asphalt and its interaction with rubber were studied, so that this knowledge could be applied to produce an alternative binder comprising bio-oil and rubber.

Thus, the work began with the study of the effects of asphalt aging in its rheological properties, in order to further understand and distinguish aging from changes in the asphalt caused by the interaction with rubber, and the effect of the asphalt on rubber particles. Processes developed for the production and investigation of various asphalt rubber components were applied in the production and study of the bio-binder (bio-oil rubber). This part of the work resulted in the production of a binder with appropriate characteristics, suggesting that it would be suitable for paving in a wide range of temperatures. Finally, this bio-binder was blended with conventional asphalt and two mixes were designed, compacted and their characteristics studied. The results showed that these mixes have excellent characteristics to be used in pavement construction.