Modified marshall mix design method for asphalt roads in hot and arid climate

Abstract

Rheological properties of asphalt mix materials, prevailing temperatures, level and rate of loading time have substantial effects on the performance of asphalt concrete pavements. Thus, they must be given appropriate consideration during asphalt mix design. Most of all developing countries rely on the empirical Marshall mix design (MMD) method to obtain homogeneous mixtures for asphalt roads. However, the MMD method does not take into account the climatic conditions, the level of compaction, and the asphalt binder properties required for hot and arid climates. The migration to more appropriate asphalt mix design methods such as the Superpave method, requires the purchase of expensive equipment, training of operators, and excludes all the laboratories, and the equipment currently used in these countries for asphalt mix design. The solution proposed in this thesis is to resort to a hybrid approach whereby the traditional MMD method is enhanced to also consider the environmental conditions of these regions. This approach is based on the integration of the characteristics of new asphalt binders (performance grade or modified asphalt) and the compaction test performed with the gyratory compactor as associated to the Superpave mix design (SMD) method. This proposed Modified Marshall Method (3M) is cost-effective because it does not require expensive equipment and tools (except the gyratory compactor), is relatively easy-to-use, and does not require substantial training for operators and engineers. The results of the laboratory investigations conducted as part of this thesis show substantial improvement of the properties of asphalt mixtures and an equally substantial increase in performance, indicative of extended pavement life in hot and arid (HA) climates with minimal additional equipment as proposed in modified Marshall method.

Date	30 Mar 2020
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Gabriel J. Assaf (Supervisor)