Influence of high content of reclaimed asphalt on the mechanical properties of cement-treated base under critical environmental conditions

Abstract

The influence of reclaimed asphalt pavement (RAP) on the mechanical properties of cement-treated materials (CTMs) has not been completely understood, while its usage as a partial supplement of virgin aggregates in road layers has been investigated by many researchers for its eco-friendly aspects. In addition, CTMs containing high contents of RAP have not yet been widely applied. Therefore, this paper aimed to experimentally investigate cement-treated base mixtures containing high percentages of RAP in terms of mechanical properties in different environmental conditions to find a proper opportunity to increase the recycling rate of this valuable material. In this regard, mixture design formulation was determined based on modified effort compaction test results as well as unconfined compressive strength and indirect tensile strength tests of seven-days cured samples. Also, critical condition of hot-summer and wet winter circumstances were taken in to account as prepared cylinder samples were dry-cured under 50 °C and wet-cured under 25 °C, respectively. Results indicate that incorporation of RAP materials increases optimum moisture content (OMC), and therefore, reduces maximum dry density (MDD). Additionally it is found that, temperature of 50 °C in RAP incorporated mixes and moisture in control mixes are critical conditions for determining strengths and finally, structural design of pavement.

Keywords:

• Cement-treated base
• RAP
• optimum moisture content
• maximum dry density
• UCS
• ITS