4.1. Effect of variances in constructed layer thickness and properties
As with any other construction, there are always some variances
in the constructed layer thicknesses and properties of the test
sections in the box (Tables 2 and 3). In order to quantify the uncertainty
introduced by the differences in the constructed test
sections, a relatively simple analysis, using AASHOTOWare Pavement
ME Design 2.2 (AASHTO, 2015), was performed to assess the
impact of variation in layer properties and thicknesses, and thereby
provide insight into the significance of the observed TBR values.
The traffic load was applied using a single tire through special axle
configuration available in Pavement-ME software. The load is 40 kN
(9000 lbf) with a tire pressure of 550 kPa (80 psi), which results in a
circular loading area of radius 152mm(6 in). This load magnitude is
consistent with that in cyclic plate load tests. The self-defined
climate file, which includes temperature, precipitation, wind
speed, percent sunshine, and hourly ground water depth, was used
to simulate the environmental condition of the laboratory cyclic
plate load tests. The resilient moduli (Mr) for the base and subgrade
layer were evaluated using the California bearing ratio CBReDCPI