relationship suggested by Webster et al. (1992) and MreCBR relationship
suggested by Powell et al. (1984).
CBR ¼292
.
ðDCPIÞ1:12
MrðMPaÞ ¼ 17:58CBR0:64
0MrðMPaÞ ¼ 665:06
.
ðDCPIÞ0:7168
(2)
The number of ESALs needed to reach 12.5 mm, 19.1 mm, and
25.4 mm rut depth was calculated for each test section taking into
consideration the measured layer's thickness and properties
(Tables 2 and 3) to quantify the effect of construction variations on
the analysis of test results. For the reinforced test sections, the
comparison was made with respect to its corresponding unreinforced
condition, i.e. without geosynthetic reinforcement. The results
of the analyses are presented in Table 5. In the table, the
variation factor (VF) was introduced to evaluate the effect of differences
in constructed layer thickness and properties on the
calculated TBR values. The VF is defined here as the number of
ESALs at a specific rut depth (i.e., 12.7 mm, 19.1 mm, and 25.4 mm)
carried by the corresponding unreinforced condition of the reinforced
test section divided by that of the control test section. By
dividing the TBR values by the VF factors, the adjusted TBR (TBRadj)
was obtained for each reinforced test section and are presented in
Table 5. It should be pointed out here that the estimated TBRadj
values can be affected by the accuracy of modulus test results for
HMA, the variation in DCP test profiles for base layer, accuracy in
measuring thicknesses of HMA and base layer, and reliability of the
correlation equations used.