Review of The LongTerm Pavement Performance (LTPP)
Backcalculation ResultsSection 508 Compliant Captions
 Figure 1. Equation. Composite
subgrade modulus at an offset.
 E subscript 0, R equals the multiplication
of: 0.84, A squared, and sigma subscript 0. This
product is divided by the product of D subscript
R and R, where E subscript 0,
R equals surface or composite modulus of the subgrade
beneath the sensor, A equals the radius of the FWD loading
plate, sigma subscript 0 equals the peak pressure of FWD
impact load under loading plate, D subscript R
equals the peak FWD deflection reading at offset distance
R, and R equals distance of deflection reading
D subscript R from center of loading plate.
 Figure 2. Equation. Hogg subgrade
modulus.
 E subscript 0 equals the product of the
following: I times the sum of 1 plus mu subscript 0, this
sum times the sum of 3 minus 4 times mu subscript 0, the
result of this expression is divided by 2 times the sum of 1 minus
mu subscript 0. This product times S subscript
0 divided by S, times P divided by the
product of delta subscript 0 times l, where E
subscript 0 equals the subgrade modulus, mu subscript
0 equals Poisson’s ratio for subgrade, S
subscript 0 is the theoretical point load stiffness,
S is the pavement stiffness, P equals the applied
load and delta subscript 0 equals the deflection at center
of load plate.
 Figure 3. Equation. Offset
distance where deflection is half of center deflection.
 The equation is R subscript 50 equals
R times the following expression: 1 over alpha raised to
one over beta, this result minus B. The result of this
expression is divided by the following expression: 1 over alpha
times the sum of delta subscript 0 divided by delta
subscript R minus 1. This product is raised by 1 over beta
and the result is subtracted by B, where delta subscript
R equals deflection at center of load plate, R
subscript 50 equals the offset distance where delta
subscript R divided by delta subscript 0 equals
0.5, and alpha and beta are curve fitting coefficients.
 Figure 4. Equation. Characteristic
length of deflection basin.
 The equation L equals Y subscript 0
times R subscript 50 over 2 plus the following
expression: the square of Y subscript 0 times
R subscript 50 minus 4 times mar
subscript 50 and the result raised to 1 over 2. If
A over l is less than 0.2, then L equals
the sum of Y subscript 0 minus 0.2 times
M, this sum times R subscript 50, where
L equals characteristic length, Y subscript
0 and M equal characteristic length
coefficients.
 Figure 5. Equation. Theoretical
point load stiffness/pavement stiffness ratio.
 S subscript 0 over S equals 1 minus
M bar times A over L minus 0.2. If
A over L is less than 0.2 then S
subscript 0 over S equals 1, where M bar
equals stiffness ratio coefficient.
 Figure 6. Equation. Composite
modulus under FWD load plate.
 E subscript 0 equals 1.5 times A
times sigma subscript 0 divided by D subscript
0,.where E subscript 0 equals the
composite modulus of the entire pavement system under the load
plate, A equals the radius of the FWD load plate, sigma
subscript 0 equals the peak pressure of FWD impact load
under the load plate and D subscript 0 equals the
peak center FWD deflection reading.
 Figure 7. Equation. 36inch AREA
equation for rigid pavements.
 A subscript 36 equals 6 times the sum of 1
plus 2 times D subscript 12 over D
subscript 0 plus 2 times D subscript 24
over D subscript 0 plus D subscript
36 over D subscript 0 where A
subscript 36 equals area under the first 36 inches (914
millimeters) of the deflection basin, and D subscript
12, D subscript 24, D subscript 36 are
deflection measured one, two and three feet, respectively, from the
center of the plate.
 Figure 8. Equation. 12inch AREA
equation for flexible pavements.
 A subscript 12 equals to 2 times the sum of 2
plus 3 times D subscript 8 over D
subscript 0 plus D subscript 12 over
D subscript 0, where A subscript
12 equals area under the first 12 inches (305 millimeters)
of the deflection basin, and D subscript 8, D
subscript 12 are deflection measured eight and twelve
inches from the center of the plate.
 Figure 9. Equation. Area factor
for rigid pavements.
 AF subscript PCC equals the following
expression: K subscript 2 minus 1 divided by the
sum of K subscript 2 minus AREA
subscript 36 over K subscript 1. The
result of this expression is raised to 1.79, where AF
subscript PCC equals the improvement in AREA from 11.04 to
1.79 power, K subscript 1 equals11.04or the AREA
when the stiffness of the concrete layer is the same as the lower
layers and K subscript 2 equals 3.262, the
maximum possible improvement in AREA.
 Figure 10. Equation. Area factor
for flexible pavements.
 AF subscript AC equals the following
expression: K subscript 2 minus 1 divided by the
sum of K subscript 2 minus AREA
subscript 12 over K subscript 1. The
result of this expression is raised to 1.35, where AF
subscript AC equals AREA factor or improvement in AREA to
the 1.35 power, K subscript 1 equals 6.85 or the
AREA when the stiffness of the asphalt layer is the same as the
lower layers and K subscript 2 equals 1.752, the
maximum possible improvement in AREA.
 Figure 11. Equation. Stiffness
or modulus of the upper PCC layer.
 E subscript PCC equals E subscript
0 times AF subscript PCC times
K subscript 3 raised to 1 over AF
subscript PCC. This product is divided by K
subscript 3 raised to 2.38, where E subscript
PCC equals stiffness or modulus of the upper PCC bound
layers and K subscript 3 equals thickness ratio
of upper layer thickness/load plate diameter.
 Figure 12. Equation. Stiffness
or modulus of the upper AC layer.
 E subscript AC equals E subscript
0 times AF subscript AC times K
subscript 3 raised to 1 over AF subscript
AC. This product is divided by K subscript
3 raised to 2, where E subscript AC
equals stiffness or modulus of the upper AC bound layers.
 Figure 13. Equation. Modulus of
the unbound base layer using the Dorman and Metcalf
relationship.
 E subscript Base equals 0.2 times H
subscript 2 raised to 0.45 times E subscript
Sub where E subscript Base equals Dorman
and Metcalf base modulus in megapascals, H subscript
2 equals thickness of the intermediate base layer in
millimeters and E subscript Sub equals the
subgrade modulus in megapascals.
 Figure 14. Graph. Back versus
forwardcalculated subgrade moduli for 15 trial LTPP flexible
sections.
 The graph depicts the power relationship between the subgrade
backcalculated modulus versus the forwardcalculated modulus ranging
from 10 to 10,000 megapascals on both axes for 15 AC test sections.
This relationship shows that the backcalculated modulus equals
1.4493 times the forwardcalculated modulus raised to 1.0355, with
an Rsquare, the coefficient of determination, of 0.3905.
 Figure 15. Graph. Back versus
forwardcalculated subgrade moduli for three trial LTPP rigid
sections.
 The graph depicts the linear relationship between the subgrade
backcalculated modulus versus the forwardcalculated modulus ranging
from 100 to 400 megapascals on the vertical axis and 100 to 300
megapascals on the horizontal axis for 3 PCC test sections. This
relationship shows that the backcalculated modulus equals 1.7436
times the forwardcalculated modulus minus 82.095, with an Rsquare
of 0.8401.
 Figure 16. Graph. Back versus
forwardcalculated asphalt layer moduli for 15 trial LTPP flexible
sections.
 The graph depicts the power relationship between the asphalt
layer backcalculated modulus versus the forwardcalculated modulus
ranging from 1,000 to 100,000 megapascals on both axes for 15 AC
test sections. This relationship shows that the backcalculated
modulus equals 1.2382 times the forwardcalculated modulus raised to
0.9617, with an Rsquare of 0.6694.
 Figure 17. Graph. Back versus
forwardcalculated concrete layer moduli for three trial LTPP rigid
sections.
 The graph depicts the power relationship between the PCC
backcalculated modulus using dense liquid and elastic solid methods
versus the forwardcalculated modulus ranging from 10,000 to 100,000
megapascals on the vertical axis and 10,000 to 1 million
megapascals on the horizontal axis for 3 PCC test sections. These
relationships show that the dense liquid backcalculated modulus
equals 1304.8 times the forwardcalculated modulus raised to 0.346,
with Rsquare of 0.6139; and the elastic solid backcalculated
modulus equals 390.26 times the forwardcalculated modulus raised to
0.4313, with an Rsquare of 0.6955.
 Figure 18. Graph. Back versus
forwardbased base layer moduli for 15 flexible LTPP sections.
 This graph depicts the power relationship between the
backcalculated versus pseudobackcalculated modulus of the
intermediate layer ranging from 1 to 100,000 megapascals on both
axes for 15 AC test sections. This relationship shows that the
backcalculated modulus equals 2.0137 times the forwardcalculated
modulus raised to 0.7852, with an Rsquare of 0.1503.
 Figure 19. Graph. Back versus
forwardcalculated asphalt layer moduli for one trial LTPP flexible
section with two upper (bound) layers.
 This graph depicts the power relationship between the second
backcalculated versus the forwardcalculated modulus of the surface
layer ranging from 1,000 to 100,000 megapascals on both axes for 15
AC test sections. This relationship shows that the backcalculated
modulus equals 60 million times the forwardcalculated modulus
raised to 1.0511, with an Rsquare of 0.0932.
 Figure 20. Graph. Back versus
forwardcalculated subgrade moduli for five trial LTPP flexible
sections with two subgrade (lower unbound) layers.
 This graph depicts the power relationship between the second
backcalculated versus the forwardcalculated modulus of subgrade
ranging from 10 to 100,000 megapascals on both axes for 5 trial AC
test sections. This relationship shows that the backcalculated
modulus equals 203.83 times the forwardcalculated modulus raised to
0.173, with an Rsquare of 0.0054.
 Figure 21. Graph. Back versus
forwardcalculated base course moduli for four trial LTPP flexible
sections with two intermediate layers.
 This graph depicts the power relationship between the second
backcalculated versus the forwardcalculated modulus of the
intermediate layer ranging from 10 to 100,000 megapascals on both
axes for 4 trial AC test sections. This relationship shows that the
backcalculated modulus equals 2 times 10 raised to 15 times the
forwardcalculated modulus raised to 5.1193, with an Rsquare of
0.294.
 Figure 22. Equation.
Interquartile range.
 IQR equals Q subscript 3 minus
Q subscript 1 where Q subscript
3 equals the twentyfifth quartile and Q
subscript 1 equals the seventyfifth quartile of the logs
of the moduli.
 Figure 23. Charts. Screening
results of the elastic moduli of the subgrade for all flexible
sections in the MON_DEFL_FLX_BAKCALC_POINT table based on the
linear elastic model (the level E records only).
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 428,026 records (97 percent) and the backcalculated
assumed values are 13,938 (3 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 367,897 records (86 percent) with both
values reasonable, 259 (0 percent) with only backcalculated values
reasonable, 59,870 (14 percent) with only forwardcalculated values
reasonable, and 417 (0 percent) with both values unreasonable. The
right pie chart represents a breakdown of both values reasonable
from the middle pie chart showing 145,518 records (39 percent)
acceptable, 91,965 (25 percent) marginal, 88,007 (24 percent)
questionable, and 42,407 (12 percent) unacceptable.
 Figure 24. Charts. Screening
results of elastic moduli of the subgrade for all the flexible
sections in the MON_DEFL_FLX_BAKCALC_POINT table based on the
linear elastic model (contains both level E and nonlevel E
records).
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 557,528 records (96 percent) and the backcalculated
assumed values are 22,494 (4 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 459,107 records (83 percent) with both
values reasonable, 946 (0 percent) with only backcalculated values
reasonable, 96,242 (17 percent) with only forwardcalculated values
reasonable, and 1,233 (0 percent) with both values unreasonable.
The right pie chart represents a breakdown of both values
reasonable from the middle pie chart showing 175,162 records (38
percent) acceptable, 115,197 (25 percent) marginal, 110,941 (24
percent) questionable, and 57,807 (12 percent) unacceptable.
 Figure 25. Charts. Screening
results of elastic moduli of the asphalt concrete layer for the
flexible sections in the MON_DEFL_FLX_BAKCALC_POINT table based on
the linear elastic model.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 205,458 records (99 percent) and the backcalculated
assumed values are 1,352 (1 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 179,440 records (88 percent) with both
values reasonable, 8,558 (4 percent) with only backcalculated
values reasonable, 12,981 (6 percent) with only forwardcalculated
values reasonable, and 4,479 (2 percent) with both values
unreasonable. The right pie chart represents a breakdown of both
values reasonable from the middle pie chart showing 127,164 records
(71 percent) acceptable, 25,543 (14 percent) marginal, 14,930 (8
percent) questionable, and 11,803 (7 percent) unacceptable.
 Figure 26. Charts. Screening
results of elastic moduli of the subgrade for the flexible sections
in the MON_DEFL_FLX_BAKCALC_POINT table based on the linear elastic
model.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 557,528 records (96 percent) and the backcalculated
assumed values are 22,494 (4 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 459,107 records (83 percent) with both
values reasonable, 946 (0 percent) with only backcalculated values
reasonable, 96,242 (17 percent) with only forwardcalculated values
reasonable, and 1,233 (0 percent) with both values unreasonable.
The right pie chart represents a breakdown of both values
reasonable from the middle pie chart showing 175,162 records (38
percent) acceptable, 115,197 (25 percent) marginal, 110,941 (24
percent) questionable, and 57,807 (13 percent) unacceptable.
 Figure 27. Charts. Screening
results of elastic moduli of the base layer for the flexible
sections in the MON_DEFL_FLX_BAKCALC_POINT table based on the
linear elastic model.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 181,056 records (97 percent) and the backcalculated
assumed values are 6,255 (3 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 119,747 records (66 percent) with both
values reasonable, 6,011 (3 percent) with only backcalculated
values reasonable, 47,109 (26 percent) with only forwardcalculated
values reasonable, and 8,189 (5 percent) with both values
unreasonable. The right pie chart represents a breakdown of both
values reasonable from the middle pie chart showing 38,373 records
(32 percent) acceptable, 29,659 (25 percent) marginal, 29,678 (25
percent) questionable, and 22,037 (18 percent) unacceptable.
 Figure 28. Charts. Screening
results of elastic moduli of the asphalt concrete layer for the
flexible sections in the MON_DEFL_FLX_ NMODEL_POINT table based on
the nonlinear elastic model.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 37,551 records (100 percent) and the backcalculated
assumed values are 86 (0 percent). The middle pie chart represents
a breakdown of backcalculated values not assumed from the left pie
chart showing 32,256 records (86 percent) with both values
reasonable, 1,252 (3 percent) with only backcalculated values
reasonable, 3,254 (9 percent) with only forwardcalculated values
reasonable, and 789 (2 percent) with both values unreasonable. The
right pie chart represents a breakdown of both values reasonable
from the middle pie chart showing 18,429 records (57 percent)
acceptable, 5,955 (18 percent) marginal, 4,085 (13 percent)
questionable, and 3,787 (12 percent) unacceptable.
 Figure 29. Charts. Screening
results of elastic moduli of the base layer for the flexible
sections in the MON_DEFL_FLX_ NMODEL_POINT table based on the
nonlinear elastic model
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 19,639 records (99 percent) and the backcalculated
assumed values are 232 (1 percent). The middle pie chart represents
a breakdown of backcalculated values not assumed from the left pie
chart showing 13,265 records (67 percent) with both values
reasonable, 526 (3 percent) with only backcalculated values
reasonable, 5,540 (28 percent) with only forwardcalculated values
reasonable, and 308 (2 percent) with both values unreasonable. The
right pie chart represents a breakdown of both values reasonable
from the middle pie chart showing 4,970 records (37 percent)
acceptable, 3,128 (24 percent) marginal, 3,025 (23 percent)
questionable, and 2,142 (16 percent) unacceptable.
 Figure 30. Charts. Screening
results of elastic moduli of the subgrade for the flexible sections
in the MON_DEFL_FLX_ NMODEL_POINT table based on the nonlinear
elastic model.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 70,742 records (97 percent) and the backcalculated
assumed values are 2,427 (3 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 61,399 records (87 percent) with both
values reasonable, 7 (0 percent) with only backcalculated values
reasonable, 9,293 (13 percent) with only forwardcalculated values
reasonable, and 43 (0 percent) with both values unreasonable. The
right pie chart represents a breakdown of both values reasonable
from the middle pie chart showing 23,329 records (38 percent)
acceptable, 15,543 (25 percent) marginal, 14,097 (23 percent)
questionable, and 8,430 (14 percent) unacceptable.
 Figure 31. Equation. PCC slab
modulus—100 percent unbonded case.
 E subscript 1 equals H subscript 1 cubed divided by the sum of
H subscript 1 cubed plus beta times H subscript 2 cubed. This
quotient times E subscript PCC, APP, where E subscript PCC, APP
equals the apparent modulus of the PCC layer with no base course
effect, E subscript 1 equals modulus of the upper plate (PCC
layer), H subscript 1 equals thickness of the upper plate (PCC
slab), H subscript 2 equals thickness of the lower plate (base
layer), and beta equals the modular ratio.
 Figure 32. Equation. PCC slab
modulus—100 percent bonded case.
 E subscript 1 equals the division of
H subscript 1 cubed by the following expression:
the sum of H subscript 1 cubed plus beta times
H subscript 2 cubed plus 12 times the square of
X minus H subscript 1 divided by 2, end
of square, plus 12 times beta times H subscript 2
times the square of H subscript 1 minus
X plus H subscript 2 divided by 2, end
of square, end of expression. This quotient times E
subscript lowercase E.
 Figure 33. Equation. Layer
thickness relationship—both cases.
 The equation X equals the division of the following
expression: H subscript 1 squared over 2 plus
beta times H subscript 2 times the sum of
H subscript 1 plus H subscript
2 over 2, end of expression, divided by the sum of
H subscript 1 plus beta times H
subscript 2.
 Figure 34. Equation. Modular
ratio b—both cases.
 The equation beta equals E subscript 2
divided by E subscript 1, where E
subscript 2 equals modulus of the lower plate (base
layer).
 Figure 35. Charts. Screening
results of elastic moduli of the interior concrete slab for the
rigid sections in the MON_DEFL_FLX_BAKCALC_POINT table based on the
linear elastic model for backcalculation and a bonded condition
between the slab and base for forwardcalculation.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 11,555 records (100 percent) and the backcalculated
assumed values are 45 (0 percent). The middle pie chart represents
a breakdown of backcalculated values not assumed from the left pie
chart showing 9,955 records (86 percent) with both values
reasonable, 442 (4 percent) with only backcalculated values
reasonable, 848 (7 percent) with only forwardcalculated values
reasonable, and 310 (3 percent) with both values unreasonable. The
right pie chart represents a breakdown of both values reasonable
from the middle pie chart showing 6,155 records (61 percent)
acceptable, 2,044 (21 percent) marginal, 1,379 (14 percent)
questionable, and 377 (4 percent) unacceptable.
 Figure 36. Charts. Screening
results of elastic moduli of the interior concrete slab for the
rigid sections in the MON_DEFL_FLX_BAKCALC_POINT table based on the
linear elastic model for backcalculation and an unbonded condition
between the slab and base for forwardcalculation.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 11,555 records (100 percent) and the backcalculated
assumed values are 45 (0 percent). The middle pie chart represents
a breakdown of backcalculated values not assumed from the left pie
chart showing 10,072 records (87 percent) with both values
reasonable, 325 (3 percent) with only backcalculated values
reasonable, 617 (5 percent) with only forwardcalculated values
reasonable, and 541 (5 percent) with both values unreasonable. The
right pie chart represents a breakdown of both values reasonable
from the middle pie chart showing 8,339 records (83 percent)
acceptable, 1,536 (15 percent) marginal, 176 (2 percent)
questionable, and 21 (0 percent) unacceptable.
 Figure 37. Charts. Screening
results of elastic moduli of the base layer for the rigid sections
in the MON_DEFL_FLX_BAKCALC_POINT table based on the linear elastic
model for backcalculation and a bonded condition between the
concrete slab and base layer for forwardcalculation.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 6,762 records (46 percent) and the backcalculated
assumed values are 7,933 (54 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 2,171 records (32 percent) with both
values reasonable, 861 (13 percent) with only backcalculated values
reasonable, 2,547 (38 percent) with only forwardcalculated values
reasonable, and 1,183 (17 percent) with both values unreasonable.
The right pie chart represents a breakdown of both values
reasonable from the middle pie chart showing 747 records (35
percent) acceptable, 398 (18 percent) marginal, 461 (21 percent)
questionable, and 565 (26 percent) unacceptable.
 Figure 38. Charts. Screening
results of elastic moduli of the base layer for the rigid sections
in the MON_DEFL_FLX_BAKCALC_POINT table based on the linear elastic
model for backcalculation and an unbonded condition between the
concrete slab and base layer for forwardcalculation.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 6,762 records (46 percent) and the backcalculated
assumed values are 7,933 (54 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 2,133 records (32 percent) with both
values reasonable, 899 (13 percent) with only backcalculated values
reasonable, 2,587 (38 percent) with only forwardcalculated values
reasonable, and 1,143 (17 percent) with both values unreasonable.
The right pie chart represents a breakdown of both values
reasonable from the middle pie chart showing 661 records (31
percent) acceptable, 392 (18 percent) marginal, 525 (25 percent)
questionable, and 555 (26 percent) unacceptable.
 Figure 39. Charts. Screening
results of elastic moduli of the subgrade for the rigid sections in
the MON_DEFL_FLX_BAKCALC_POINT table based on the linear elastic
model.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 10,220 records (88 percent) and the backcalculated
assumed values are 1,380 (12 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 8,970 records (88 percent) with both
values reasonable, 0 (0 percent) with only backcalculated values
reasonable, 1,249 (12 percent) with only forwardcalculated values
reasonable, and 1 (0 percent) with both values unreasonable. The
right pie chart represents a breakdown of both values reasonable
from the middle pie chart showing 4,440 records (50 percent)
acceptable, 1,184 (13 percent) marginal, 1,172 (13 percent)
questionable, and 2,174 (24 percent) unacceptable.
 Figure 40. Charts. Screening
results of elastic moduli of the PCC slab for the rigid sections in
the MON_DEFL_RGD_BAKCALC_POINT table using the elastic solid model
for backcalculation and assuming bonded condition between the slab
and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 33,777 records (98
percent) with both values reasonable, 855 (2 percent) with only
backcalculated values reasonable, 14 (0 percent) with only
forwardcalculated values reasonable, and 106 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 32,761 records (97 percent)
acceptable, 936 (3 percent) marginal, 80 (0 percent) questionable,
and 0 (0 percent) unacceptable.
 Figure 41. Charts. Screening
results of elastic moduli of the PCC slab for the rigid sections in
the MON_DEFL_RGD_BAKCALC_POINT table using the elastic solid model
for backcalculation and assuming unbonded condition between the
slab and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 32,511 records (96
percent) with both values reasonable, 975 (3 percent) with only
backcalculated values reasonable, 137 (0 percent) with only
forwardcalculated values reasonable, and 433 (1 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 32,278 records (99 percent)
acceptable, 210 (1 percent) marginal, 23 (0 percent) questionable,
and 0 (0 percent) unacceptable.
 Figure 42. Charts. Screening
results of elastic moduli of the base layer for the rigid sections
in the MON_DEFL_RGD_BAKCALC_POINT table using the elastic solid
model for backcalculation and assuming bonded condition between the
slab and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 30,955 records (92
percent) with both values reasonable, 129 (0 percent) with only
backcalculated values reasonable, 1,991 (6 percent) with only
forwardcalculated values reasonable, and 777 (2 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 29,544 records (96 percent)
acceptable, 737 (2 percent) marginal, 100 (0 percent) questionable,
and 574 (2 percent) unacceptable.
 Figure 43. Charts. Screening
results of elastic moduli of the base layer for the rigid sections
in the MON_DEFL_RGD_BAKCALC_POINT table using the elastic solid
model for backcalculation and assuming unbonded condition between
the slab and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 31,199 records (94
percent) with both values reasonable, 202 (1 percent) with only
backcalculated values reasonable, 1,019 (3 percent) with only
forwardcalculated values reasonable, and 736 (2 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 29,677 records (95 percent)
acceptable, 356 (1 percent) marginal, 332 (1 percent) questionable,
and 834 (3 percent) unacceptable.
 Figure 44. Charts. Screening
results of elastic moduli of the subgrade for the rigid sections in
the MON_DEFL_RGD_BAKCALC_POINT table using the elastic solid model
for backcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 35,878 records (100
percent) with both values reasonable, 0 (0 percent) with only
backcalculated values reasonable, 6 (0 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 35,529 records (99 percent)
acceptable, 346 (1 percent) marginal, 3 (1 percent) questionable,
and 0 (0 percent) unacceptable.
 Figure 45. Charts. Screening
results of elastic moduli of the PCC slab for the rigid sections in
the MON_DEFL_RGD_BAKCALC_POINT table using the dense liquid model
for backcalculation and assuming bonded condition between the slab
and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 34,727 records (96
percent) with both values reasonable, 573 (2 percent) with only
backcalculated values reasonable, 389 (1 percent) with only
forwardcalculated values reasonable, and 188 (1 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 32,094 records (92 percent)
acceptable, 2,632 (8 percent) marginal, 1 (0 percent) questionable,
and 0 (0 percent) unacceptable.
 Figure 46. Charts. Screening
results of elastic moduli of the PCC slab for the rigid sections in
the MON_DEFL_RGD_BAKCALC_POINT table using the dense liquid model
for backcalculation and assuming unbonded condition between the
slab and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 31,256 records (96
percent) with both values reasonable, 168 (1 percent) with only
backcalculated values reasonable, 965 (3 percent) with only
forwardcalculated values reasonable, and 101 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 27,790 records (89 percent)
acceptable, 3,465 (11 percent) marginal, 1 (0 percent)
questionable, and 0 (0 percent) unacceptable.
 Figure 47. Charts. Screening
results of elastic moduli of the base layer for the rigid sections
in the MON_DEFL_RGD_BAKCALC_POINT table using the dense liquid
model for backcalculation and assuming bonded condition between the
slab and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 32,712 records (94
percent) with both values reasonable, 767 (2 percent) with only
backcalculated values reasonable, 1,135 (3 percent) with only
forwardcalculated values reasonable, and 348 (1 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 29,221 records (90 percent)
acceptable, 2,358 (7 percent) marginal, 464 (1 percent)
questionable, and 669 (2 percent) unacceptable.
 Figure 48. Charts. Screening
results of elastic moduli of the base layer for the rigid sections
in the MON_DEFL_RGD_BAKCALC_POINT table using the dense liquid
model for backcalculation and assuming unbonded condition between
the slab and the base for back and forwardcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 29,813 records (94
percent) with both values reasonable, 719 (2 percent) with only
backcalculated values reasonable, 817 (3 percent) with only
forwardcalculated values reasonable, and 227 (1 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 25,245 records (85 percent)
acceptable, 3,244 (11 percent) marginal, 1,041 (3 percent)
questionable, and 283 (1 percent) unacceptable.
 Figure 49. Equation. Subgrade
Kvalue.
 The equation is Kvalue equals 0.296 times E
subscript subgrade. The Rsquare equals 0.87, where
Kvalue equals subgrade modulus of reaction in kilopascals
per millimeter and E subscript subgrade equals
subgrade modulus of elasticity in megapascals.
 Figure 50. Charts. Screening
results of the subgrade kvalues for the rigid sections in the
MON_DEFL_RGD_BAKCALC_POINT table using the dense liquid model for
backcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 35,876 records (97
percent) with both values reasonable, 0 (0 percent) with only
backcalculated values reasonable, 1,111 (3 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 32,830 records (92 percent)
acceptable, 3,010 (8 percent) marginal, 36 (0 percent)
questionable, and 0 (0 percent) unacceptable.
 Figure 51. Charts. Screening
results of elastic moduli of the point base layer for the flexible
sections in the MON_DEFL_FLX_BAKCALC_POINT table based on the
linear elastic model.
 This graphic consists of three pie charts. The left one
represents all the data, where the backcalculated values not
assumed are 181,056 records (97 percent) and the backcalculated
assumed values are 6,255 (3 percent). The middle pie chart
represents a breakdown of backcalculated values not assumed from
the left pie chart showing 119,747 records (66 percent) with both
values reasonable, 6,011 (3 percent) with only backcalculated
values reasonable, 47,109 (26 percent) with only forwardcalculated
values reasonable, and 8,189 (5 percent) with both values
unreasonable. The right pie chart represents a breakdown of both
values reasonable from the middle pie chart showing 38,373 records
(32 percent) acceptable, 29,659 (25 percent) marginal, 29,678 (25
percent) questionable, and 22,037 (18 percent) unacceptable.
 Figure 52. Charts. Screening
results of elastic moduli of the section base layer for the
flexible sections in the MON_DEFL_FLX_BAKCALC_SECT table based on
the linear elastic model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 2,505 records (74
percent) with both values reasonable, 171 (5 percent) with only
backcalculated values reasonable, 616 (18 percent) with only
forwardcalculated values reasonable, and 118 (3 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 840 records (34 percent) acceptable,
601 (24 percent) marginal, 636 (25 percent) questionable, and 428
(17 percent) unacceptable.
 Figure 53. Charts. Screening
results of the subgrade point Kvalue table for the rigid sections
in the MON_DEFL_RGD_BAKCALC_POINT table using the dense liquid
model for backcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 35,876 records (97
percent) with both values reasonable, 101 (0 percent) with only
backcalculated values reasonable, 1,111 (3 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 32,830 records (92 percent)
acceptable, 3,010 (8 percent) marginal, 36 (0 percent)
questionable, and 0 (0 percent) unacceptable.
 Figure 54. Charts. Screening
results of the subgrade section Kvalue table for the rigid
sections in the MON_DEFL_RGD_BAKCALC_SECT table using the dense
liquid model for backcalculation.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,110 records (98
percent) with both values reasonable, 0 (0 percent) with only
backcalculated values reasonable, 18 (2 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 1,061 records (96 percent)
acceptable, 48 (4 percent) marginal, 1 (0 percent) questionable,
and 0 (0 percent) unacceptable.
 Figure 55. Charts. Screening
results of section average elastic moduli of the asphalt concrete
layer for the flexible sections in the MON_DEFL_FLX_BAKCALC_SECT
table based on the linear elastic model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 4,925 records (86
percent) with both values reasonable, 220 (4 percent) with only
backcalculated values reasonable, 400 (7 percent) with only
forwardcalculated values reasonable, and 155 (3 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 3,564 records (72 percent)
acceptable, 644 (13 percent) marginal, 376 (8 percent)
questionable, and 341 (7 percent) unacceptable.
 Figure 56. Charts. Screening
results of section average elastic moduli of the base layer for the
flexible sections in the MON_DEFL_FLX_BAKCALC_SECT table based on
the linear elastic model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 2,505 records (74
percent) with both values reasonable, 171 (5 percent) with only
backcalculated values reasonable, 616 (18 percent) with only
forwardcalculated values reasonable, and 118 (3 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 840 records (34 percent) acceptable,
601 (24 percent) marginal, 636 (25 percent) questionable, and 428
(17 percent) unacceptable.
 Figure 57. Charts. Screening
results of section average elastic moduli of the subgrade for the
flexible sections in the MON_DEFL_FLX_BAKCALC_SECT table based on
the linear elastic model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 9,913 records (82
percent) with both values reasonable, 8 (0 percent) with only
backcalculated values reasonable, 2,253 (18 percent) with only
forwardcalculated values reasonable, and 12 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 3,651 records (37 percent)
acceptable, 2,693 (27 percent) marginal, 2,420 (24 percent)
questionable, and 1,149 (12 percent) unacceptable.
 Figure 58. Charts. Screening
results of section average elastic moduli of the asphalt concrete
layer for the flexible sections in the MON_DEFL_FLX_BAKCALC_SECT
table based on the nonlinear elastic model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 690 records (87
percent) with both values reasonable, 40 (5 percent) with only
backcalculated values reasonable, 59 (7 percent) with only
forwardcalculated values reasonable, and 11 (1 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 438 records (63 percent) acceptable,
144 (21 percent) marginal, 59 (9 percent) questionable, and 49 (7
percent) unacceptable.
 Figure 59. Charts. Screening
results of the section average elastic moduli of the base layer for
the flexible sections in the MON_DEFL_FLX_BAKCALC_SECT table based
on the nonlinear elastic model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 377 records (78
percent) with both values reasonable, 18 (4 percent) with only
backcalculated values reasonable, 74 (16 percent) with only
forwardcalculated values reasonable, and 8 (2 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 149 records (40 percent) acceptable,
106 (28 percent) marginal, 65 (17 percent) questionable, and 57 (15
percent) unacceptable.
 Figure 60. Charts. Screening
results of the section average elastic moduli of the subgrade for
the flexible sections in the MON_DEFL_FLX_BAKCALC_SECT table based
on the nonlinear elastic model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,258 records (85
percent) with both values reasonable, 0 (0 percent) with only
backcalculated values reasonable, 219 (15 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 444 records (35 percent) acceptable,
352 (28 percent) marginal, 299 (24 percent) questionable, and 163
(13 percent) unacceptable.
 Figure 61. Charts. Screening
results of the section average elastic moduli of the PCC slab for
the rigid sections in the MON_DEFL_FLX_BAKCALC_SECT table based on
the linear elastic model using MODCOMP.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,250 records (93
percent) with both values reasonable, 4 (0 percent) with only
backcalculated values reasonable, 86 (6 percent) with only
forwardcalculated values reasonable, and 13 (1 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 1,148 records (92 percent)
acceptable, 95 (8 percent) marginal, 5 (0 percent) questionable,
and 2 (0 percent) unacceptable.
 Figure 62. Charts. Screening
results of the section average elastic moduli of the base layer for
the rigid sections in the MON_DEFL_FLX_BAKCALC_SECT table based on
the linear elastic model using MODCOMP.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 875 records (51
percent) with both values reasonable, 153 (9 percent) with only
backcalculated values reasonable, 551 (32 percent) with only
forwardcalculated values reasonable, and 129 (8 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 388 records (44 percent) acceptable,
149 (17 percent) marginal, 165 (19 percent) questionable, and 173
(20 percent) unacceptable.
 Figure 63. Charts. Screening
results of the section average elastic moduli of the subgrade for
the rigid sections in the MON_DEFL_FLX_BAKCALC_SECT table based on
the linear elastic model using MODCOMP.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,235 records (91
percent) with both values reasonable, 0 (0 percent) with only
backcalculated values reasonable, 118 (9 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 655 records (53 percent) acceptable,
158 (13 percent) marginal, 194 (16 percent) questionable, and 228
(18 percent) unacceptable.
 Figure 64. Charts. Screening
results of the section average elastic moduli of the PCC slab for
the rigid sections in the MON_DEFL_RGD_BAKCALC_SECT table based on
the slabonelasticsolid model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,150 records (99
percent) with both values reasonable, 11 (1 percent) with only
backcalculated values reasonable, 0 (0 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 1,133 records (99 percent)
acceptable, 17 (1 percent) marginal, 0 (0 percent) questionable,
and 0 (0 percent) unacceptable.
 Figure 65. Charts. Screening
results of the section average elastic moduli of the PCC slab for
the rigid sections in the MON_DEFL_RGD_BAKCALC_SECT table based on
the slabondenseliquid model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,117 records (99
percent) with both values reasonable, 8 (1 percent) with only
backcalculated values reasonable, 0 (0 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 1,077 records (97 percent)
acceptable, 39 (3 percent) marginal, 1 (0 percent) questionable,
and 0 (0 percent) unacceptable.
 Figure 66. Charts. Screening
results of the section average elastic moduli of the base layer for
the rigid sections in the MON_DEFL_RGD_BAKCALC_SECT table based on
the slabonelasticsolid model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,021 records (92
percent) with both values reasonable, 3 (0 percent) with only
backcalculated values reasonable, 61 (6 percent) with only
forwardcalculated values reasonable, and 21 (2 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 993 records (98 percent) acceptable,
14 (1 percent) marginal, 14 (1 percent) questionable, and 0 (0
percent) unacceptable.
 Figure 67. Charts. Screening
results of the section average elastic moduli of the base layer for
the rigid sections in the MON_DEFL_RGD_BAKCALC_SECT table based on
the slabondenseliquid model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,033 records (96
percent) with both values reasonable, 19 (2 percent) with only
backcalculated values reasonable, 18 (2 percent) with only
forwardcalculated values reasonable, and 4 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 966 records (94 percent) acceptable,
36 (3 percent) marginal, 31 (3 percent) questionable, and 0 (0
percent) unacceptable.
 Figure 68. Charts. Screening
results of the section average elastic moduli of the subgrade for
the rigid sections in the MON_DEFL_RGD_BAKCALC_SECT table based on
the slabonelasticsolid model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,165 records (100
percent) with both values reasonable, 0 (0 percent) with only
backcalculated values reasonable, 0 (0 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 1,158 records (99 percent)
acceptable, 7 (1 percent) marginal, 0 (0 percent) questionable, and
0 (0 percent) unacceptable.
 Figure 69. Charts. Screening
results of the section average Kvalues of the subgrade for the
rigid sections in the MON_DEFL_RGD_BAKCALC_SECT table based on the
slabondenseliquid model.
 This graphic consists of two pie charts. The left one
represents all the data, where the breakdown is 1,110 records (98
percent) with both values reasonable, 0 (0 percent) with only
backcalculated values reasonable, 18 (2 percent) with only
forwardcalculated values reasonable, and 0 (0 percent) with both
values unreasonable. The right pie chart represents a breakdown of
both values reasonable showing 1,061 records (96 percent)
acceptable, 48 (4 percent) marginal, 1 (0 percent) questionable,
and 0 (0 percent) unacceptable.
FHWAHRT05150
