105
Case 4. For 100.0 < E < 1000.0 ksi, 10.0 < E < 85.0 ksi,
1 2
and t < 2.5 in.,
1
2.5239
-0.1961 r-o.ooo0037(E )(t ) ]
K = 24.782(t ) e Eqn. 4.9
0,1173 2.9599
K = 1.1341(t ).1173 + 0.000114(E )(t )2.9599 Eqn. 4.10
2 1 1 1
Again modulus Ei is in ksi, deflection Di in mils, and thickness of
asphalt concrete t1 is ininches.
4.3.2.3 Prediction Equations for E3. The initial analysis of
Dynaflect data was performed in an attempt to select some combinations
of sensor deflection response which would provide a simple, straight-
forward method for the prediction of moduli for the 12-in. thick
stabilized subgrade. This layer was found to be the most difficult
layer for developing a rational prediction equation. Three equations
were obtained for various ranges of variables. It will later be shown
that the third E3 prediction equation presented herein was simplified
enough and had the capability of being expanded to cover a larger range
of variables.
Considerable effort was expended in analyzing the relationship
between E3 and D D This relationship was significantly affected
by E1, E2, E and t1. Preliminary analysis resulted in the development
of an equation for fixed values of E1 and ti, and variable E2 and E
values.