Material Properties Of Cold In Place Recycled And Full Depth Reclamation Asphalt Concrete PDF Download

Asphalt concrete pavements receive maintenance to retard the loss of structural integrity and functionality. A common maintenance action to address localized failures is hot mix asphalt or cold mix patches. The result of this practice is a pavement cross-section with different binder ages. The main focus of this study is to investigate the effects of different binder ages in reclaimed material included in cement stabilized bases resulting from full depth reclamation of asphalt concrete roads. The research hypothesis for this thesis is that the new asphalt binder from hot mix patches in an aged flexible pavement has no significant effect on the stiffness properties of a cement stabilized base which has been placed using full depth reclamation. Three types of material were used in this study. The first was virgin aggregate base (AB), the second was Full Depth Reclaimed Material (FDRM) which consisted of 50% rubberized reclaimed asphalt pavement and 50% virgin aggregate base, and lastly 90% Reclaimed Asphalt Pavement (RAP) with 10% virgin aggregate base. A portion of the full depth reclaimed material and a portion of the RAP were oven aged to simulate aging in the field. The material was then stabilized with 5% cement. The tests that were conducted included maximum dry density, optimum moisture content, unconfined compressive strength, indirect tensile strength, dynamic modulus and shrinkage.The main conclusions of this study were that unaged asphaltic material in full depth reclaimed bases stabilized with cement will have a lower dynamic modulus compared to cement stabilized material made from the surrounding, aged asphaltic material. The strength properties between the aged and unaged RAP and FDRM were not significantly different. This suggests that compressive and tensile strength depends primarily on the cementitious bonds, and that the age of the asphalt binder covering the aggregates does not influence the strength. Even though this will not influence the mix design of the cement stabilized base constructed with full depth reclamation, the base will have reduced stiffnesses in localized areas which are potential fatigue failure zones for the AC surface.