Abstract
The characteristics of the unbound base layer have been recognized to influence the performance of flexible pavements to wide extents depending on climate conditions, construction quality, material source, traffic level, and pavement structure. Recently, unsaturated soil modeling has become generally accepted in predicting the pavement performance as pavement layers are typically placed well above soil water table, and tend to remain unsaturated during pavement service life. This paper investigates the combined impact of compaction level and initial matric suctions of construction and demolition (C&D) waste material used as a based layer on simulated pavement performance using the AASHTOWare Pavement ME Design software. Towards the preparation of the software inputs as per level 1 requirements, a laboratory experimental program was conducted on C&D material which includes the construction of soil water characteristic curve (SWCC) and determination of resilient modulus at four different moisture contents and two levels of compaction effort. The simulated pavement performance analyses consider two climatic conditions (dry and wet), two groundwater table levels (shallow and deep), two types of subgrade soil (strong and weak), and two thickness levels for the base and asphalt surface layers (thin and thick). Full statistical analyses of the main and interaction effects were performed on the results of AASHTOWare Pavement ME Design software. The results showed that the compaction level has more significant effect on the base and subgrade rutting and bottom-up fatigue cracking than the initial matric suction. In addition, both initial matric suction and SWCC input level were found to have a significant effect on all simulated distresses. Furthermore, the interaction between the compaction and initial matric suction was found to be significant. (C) 2020 Elsevier Ltd. All rights reserved.