\

17-J-fS3/( Cj: Sv.15'

Iowa Highway Research Board

Project HR-87

SUBGRADE INSULATION

TO PREVENT

SOIL FREEZING

Final Report December 1965

Research Department

Iowa State Highway Commission

/ { .. -

IOWA STATE HIGHWAY COMMISSION Ames, Iowa

December 21, 1965

To: All Concerned

From~ Research Department

Subject: Subgrade Insulation to Prevent Soil Freezing

The report noted above .is final for research project HR-87. The automatic temperature recording equipment has been removed from the test site. Observations of the pavement will continue to be made periodically~ you will be informed of any ~ignificant changes.

The basic purpose of this study was to determine if insul­ating board composed of expanded polystyrene can be used under highway pavement to prevent freezing of the subgr~de soil.

The insulating board was furnished without cost by the manufacturer. The thickness, one and one~half inches, was that recommended by the manufacturer. 1he board was placed on the subgrade composed of a frost-susceptible soil; a nine­.inch Portland Cement Concrete slab was placed on top of the board.

The temperature of the air, the concrete, and of the. soil was obtained from thermocouples. This was recorded auto­matically every two hours. The report contains graphs and· illustrations showing temperature distributions for two years.

The insulation under a PoCo concrete slab and under the shoulders, as used in this experimental project, appears to have adequately protected the subgrade from freezing temperatures and prevented frost heave.

The concrete slab above the insulation, in comparison with the uninsulated control slab, experienced more cycles of freezing and thawing. It also appeared to have a more uniform temperature throughout its thickness.

The conclusions contained in this report do not cons.ti tute a recommendation for any particular brand nor type of thermal insulation. It may be that many suitable materials now exist or will subsequently be deve.loped. While the basic requirement is low thermal conductivity, there are also other properties which should be exhibited by the insulating material. It should absorb little or no moisture, should be unaffected by chemicals and bacteria commonly found in soil and paving materials, and should have structural strength adequate for the intended application.

-2-

This report concerns the use of thermal insulation under rigid pavement. It is recognized that the desirability of preventing soil freezing applies equally to the supporting subgrade for flexible pavement. The exact placement of the insulation under either type of pavement will depend upon individual job requirements and the ingenuity of the designer. It should be kept in mind that the installation method and its compatibility with standard construction procedures is an important factor in the cost of the project. If the installa­tion method is complicated, it will likewise be costly. In this event, the use of thermal insulation may not prove econo­mical in comparison with the conventional practice of replacing the frost-susceptible subgrade soil with granular material.

Te.~:'t Site -----~-,. ___ _ us - 18

[_J

Figure 1: Project Map

ACKNOWLEDGEMENTS

The experimental work described in this report was

accomplished through the cooperation of all concerned with the

design and construction of the pavemento The temperature

recording equipment was installed by personnel from the Materials

Department Laboratoryo Regular inspection of the installation

and profile.measurements of the pavement were provided by

personnel from the Resident Engineer's Office at New Hampton.

We desire to also acknowledge the excellent cooperation of

the paving contractor 0 Fred Carlson, and of the Dow Chemical

Company, which furnished technical assistance as well as the

Styrofoam insulation.

iii

ABSTRACT

The basic purpose of this study was to determine if an

expanded polystyrene insulating board could prevent subgrade

freezing and thereby reduce frost heave.

The insulating board was placed between a nine inch

P. c. concrete slab and a frost-susceptible subgrade. In one

section at the test site, selected backfill material was

placed under the pavement. The P. C. pavement was later

covered by asphalt surfacing. Thermocouples were installed

for obtaining temperature recordings at various locations in

the surfacing, concrete slab, subgrade and shoulders.

This report contains graphs and illustrations showing

temperature distributions for two years, as well as profile

elevations and the results of moisture tests.

iv

TABLE OF CONTENTS

Acknowledgements Abstract Introduction Research Objective Material Construction Testing Results Discussion Conclusions Photographs

Table

1 2 3

Figure

1 2

3-6 7-8 9-10

11-14

15-18

19-20 21-24

List of Tables

Title

Physical Properties of Styrofoam Scorbord SM Centerline Profile Elevations Subgrade Moisture Content

List of Figures

Title

Project Map Test Layout Thermocouple Locations Average Daily Air Temperatures Average Daily Temperatures Above and Below

the Styrofoam Concrete Temperature as Affected by

Styrofoam Temperatures at Various Depths Below the Surf ace

Determination of Freezing Indexes 0 . Depths at Which 32 F Or Less Were Recorded

v

Page

iii iv

1 2 3 3 5 6 7 9

11

16 17 19

ii 22

23-26 27-28

29-30

31-34

35-38 39-40 41-44

INTRODUCTION

Frost heave is a ground-freezing phenomenon which has

always been a problem for highway engineers. When severe

enough, localized areas develop what are commonly called

"frost boils." There is considerable vertical movement of

the road surface during winter freeze and spring thaw.

Finally, over a period of years, cracking of the slab and

uneven settlement develop giving the pavement very poor

riding qualities. In extreme conditions complete disinte­

gration of the surface can occur.

In order for frost heaving or frost boils to develop,

three basic conditions must exist. These are: (1) freezing

temperatures in the soil; (2) a reservoir of ground water

sufficiently close to the frost line to feed the growing ice

layers; (3) soil material having favorable characteristics

for rapid movement of capillary water upward from the water

table. Since the temperature cannot be controlled, frost

heave areas have generally been corrected by removing the

undesirable material and replacing it with a granular backfill

or by lowering the water table.

1

The conclusions contained in this report do not constitute

a recommendation for any particular brand nor type of thermal

insulation. It may be that many completely adequate materials

now exist or will subsequently be developed. While the basic

requirement is low thermal conductivity, there are also other

properties which should be e.xhibited by the insulating material.

It should absorb little or no moisture, should be unaffected

by chemicals and bacteria commonly found in soil and paving

materials, and should have structural strength adequate for

the intended application.

This report concerns the use of thermal insulation under

rigid pavement. It is recognized that the value of preventing

soil freezing applies equally to the supporting subgrade for

flexible pavement. The exact placement of the insulation

under either type of pavement will depend upon individual

job requirements and the ingenuity of the designer. It should

be kept in mind that the installation method and its compati­

bility with standard construction procedures is an important

factor in the cost of the project. If the installation method

is complicated, it will likewise be costly. In this event,

the use of thermal insulation will seldom prove economical in

comparison with the conventional practice of .replacing the

frost-susceptible subgrade soil with granular material.

RESEARCH OBJECTIVE

During the fall of 1963, the Iowa State Highway Commission

constructed a short section of highway where an insulating

material was placed directly below the slab. The objective

of this test was to determine if an insulating material will

2

3

prevent the subgrade from freezing, thereby reducing the frost

heave. If successful, this could eliminate the need to remove

and replace the poor soil with granular material.

The insulating material for this test was furnished with-

out cost by the manufacturer, Dow Chemical Company of Midland,

Michigan. Therefore, no attempt was made to compare the cost

of insulation with that of granular backfill.

MATERIAL

The insulating material used is an expanded polystyrene

with the trade name of Styrofoam. The physical properties of

the type of Styrofoam used in this test are shown in Table 1.

Its mechanical properties decrease slightly as the temperature

is raised. 0 0 At 160 F to 170 F the cellular structure collapses.

The material is not affected adversely at sub-zero temperatures.

Polystyrene, the base plastic, absorbs.a negligible amount

of moisture and the closed cell structure of Styrofoam almost

completely prevents the entrance of water.

CONSTRUCTION

The Iowa test section is located on US 18 about two miles

west of West Union. It is in a 450 foot- section of pavement

having a history of frost heaving.

The original plans were to core out three feet of the

subgrade and backfill with selected granular material. The

excavation and backfilling was eliminated on the east 250 feet

of the section. Instead, one and one-half inches of Styrofoam

was placed directly below the pavement on the subgrade and in

the shoulders at a 2:1 slope.

The 250 foot test area was divided into three sections.

In the east section, 75 feet in length, one layer of Styrofoam

one and one-half inches thick was placed. In the middle

section, 100 feet in length, two layers of Styrofoam, each

three-fourths inch thick, were placed. In the west section,

75 feet in length, one layer of Styrofoam one and one-half

inches thick was placed. In this section the Styrofoam was

covered with a sheet of four mil polyethelene. A layout of

the test area is shown in Figure 2.

The test sections were instrumented to measure the temp­

eratures at various locations in the slab, subgrade and

shoulders.

As soon as the pavement forms were in place and the sub­

grade cut and compacted, the first group of thermocouples was

installed at various depths in the subgrade. This was followed

by the placing of the Styrofoam between the forms. The Styro­

foam was in the form of boards, 2 foot by 8 foot. Very little

trouble was encountered in placing them, however, they were

very light and could easily be blown away by the wind. They

were fastened to the subgrade by wooden peg~.

Nine inches of Portland cement concrete pavement was then

placed directly on the Styrofoam {or polyethelene). The thermo­

couples used to measure the temperature of the concrete pave­

ment ·\.\ere heJd in position by frames during placing of the

concrete.

The next day, after the paving forms had been removed,

the 2~1 slope was cut on the shoulders. Styrofoam was then

placed along the slope and the shoulder was constructed.

Thermocouples were placed in the shoulder at various depths

in the soil below and above the Styrofoam.

About June 15, 1964, three inches of asphaltic concrete

were placed upon the nine-inch concrete slab. On May 7, 1965,

thermocouples were placed at various positions in the resurfacing.

TESTING

The thermocouple wires terminated in a 5 foot by 5 foot by

6 foot building located near the right of way line. This

building was well insulated and a temperature above 50°F was

easily maintained during the winter months by use of two

electric heaters.

The temperatures obtained by the thermocouples were indi­

cated by an automatic recording potentiometer which was capable

of recording, in sequence, the temperatures in 24 separate

locations. It was timed so that the temperatures at the 24

locations were recorded once every two hours. The recorder

contained two instrument boards consisting of 24 terminals

each. Either board could be connected, making it possible to

obtain temperatures from 24 alternate locations if desired.

The layout of the thermocouples at Station 602+00 and at

Station 604+50 is shown in Figures 3 and 4.

Figures 5 and 6 show the thermocouple locations at the

same stations after the asphaltic concrete resurfacing had

been completed. The remaining thermocouples were placed in

the concrete and subgrade at Station 603+50 but were not

installed in the resurfacing at that particular location.

5

RESULTS

Graphs and illustrations of the temperatures at various

locations are shown in Figures 7 through 24.

Figures 7 and 8 show the average daily air temperatures

during the freezing seasons of 1963-1964 and 1964-1965.

Figures 9 and 10 compare the temperatures above and below

the Styrofoam insulation. Figure 9 shows these comparative

temperatures for the 1963-1964 freezing season (before

resurfacing) and Figure 10 shows them for the 1964-1965 freezing

season (after resurfaci~g)~

Figures 11 and 12 compare minimum temperatures in the

concrete one inch above the bottom of the slab, as affected

by insulation below the slab. These graphs are included

primarily to show that while the Styrofoam insulates the sub­

grade from freezing temperatures, it also prevents the concrete

from receiving heat from the subgrade. Figures 13 and 14 show

maximum temperatures at the same locations during the warmest

summer months. In this case the Styrofoam reduces the amount

of cooling from the subgrade. The temperatures shown in

Figure 11 are those before the asphaltic concrete was applied

and those in Figuresl2, 13, and 14 are after the three inch

resurfacing.

Figures 15, 16, 17, and 18 show minimum and maximum

temperatures at various depths below the surface with and

without the Styrofoam insulation. It should be noted that

during the winter of 1963-1964 the minimum temperature one inch

above the Styrofoam was -15°F while the minimum temperature

6

one inch below the styrofoam was 34°F. During the winter of

1964-1965, however, the minimum temperature one inch above

0 the Styrofoam was -8 F and the minimum temperature one inch

below the styrofoam dropped to 30°F. During the 1964-1965

winter the subgrade temperature five inches below the styrofoam

0 dropped below 32 F for a period of five days.

DISCUSSION

In order to accurately evaluate the results obtained on

a field installation such as this, it becomes necessary to

determine whether or not the installation was put to a severe

enough test.

A commonly accepted method for determining the severity

of cold weather is to calculate the freezing index for the

winter or winters in question.

Definitions:

Average daily temperature - The average of the maximum and

minimum temperatures for one day or the average of several

temperature readings taken at equal time intervals· during one

day.

Mean daily temperature - The average of the average daily

temperatures for a given day for several years.

Degree-days - The degree-days for any one day equals the dif­

o ference between the average daily air temperature and 32 F.

The degree-days are minus when the average daily temperature

is below 32°F (freezing degree-days) and plus when above 32°F

(thawing degree-days).

7

Freezing index - The number of degree-days between the highest

and lowest points on. a curve of cumulative degree-days versus

time for one freezing season. It is a measure of the combined

duration and magnitude of below freezing temperatures occurring

during any given freezing season. The index determined for

air temperatures at 4.5 feet above the ground is commonly

designated as the air freezing index, and that determined for

temperatures immediately below a surface is known as the sur­

face freezing index.

Design freezing index - 'I'he average air freezing index of the

three coldest winters in the latest 30 years of record. If

30 years are not available, the air freezing index for the

coldest winter in the latest 10 year period may be used.

Mean Freezing Index - The freezing index determined on the

basis of mean temperatures. The period of record over which

temperatures are averaged is usually a minimum of 10 years

(preferably 30) and should be the latest available.

Figure 19 shows the freezing index to be 1463 degree-days

for the 1963-1964 freezing season. Figure 20 shows the freezing

index for the 1964-1965 freezing season has a value of 2035

degree-days. The mean freezing index for this part of the state

as determined by the U.S. Army Corps of Engineers is 1100

degree-days over a 105 day period and the design freezing index

is 1700 degree-days. From these figures it can be seen that

the 1963-1964 winter was somewhat colder than average for

this area, and the 1964-1965 winter was very severe. Mr. Paul

J. Waite, Weather Bureau State Climatologist, speaking of the

8

1964-1965 winter says it was "the coldest winter (December

through March) since 1935-1936. Subnormal temperatures occurred

throughout all four months."

Figures 21 through 24 show the depth of frost penetration

down to and including 46 inches below the top of the P.C.

concrete in the section containing the granular backfill

material.

Profile elevations of the roadway were taken at various

times during the course of the investigation to determine the

amount of frost heave. Table 2 shows that elevation changes

in the styrofoam sections were much less than those either in

the special backfill section or outside the test sections.

Moisture samples of the subgrade and shoulder were taken

in April, 1964 and May, 1965. These values are listed in

Table 3 and appear to have little significance. The subgrade

in the control section consists of 3 feet of granular backfill

which normally has a much lower moisture content than the fine

grained soil under the Styrofoam.

CONCLUSIONS

The Styrofoam insulation under a P.C. concrete slab and

under the shoulders, as used in this experimental project,

appears to have adequately protected the subgrade from freezing

temperatures and prevented frost heave.

Because of an insulating layer under the concrete slab

it is known that the slab undergoes more freeze-thaw cycles

than it would if such an insulating layer were not present.

Whether or not this is detrimental remains to be seen.

9

The concrete slab above the Styrofoam appears to maintain

a more uniform temperature throughout its depth than does a

slab resting on the subgra.de. The a.dvantages gained from this

due to a reduction in curling of the slab is beyond the scope

of this report.

10

first thermocou0le

Photo !, .~

Pooden pegs QSed to fasten the r

I ,

P11.c>~tc> Dn the

Photo 5. :on~ret~ bein p11L::ec. on the Styrofoam.

Photo s~ CuttLns- the 2~1 Shoulder Slope :Eor

Photo 7~ Styrof'::>a~r1 'Jein~' placecl on the 2~1 Slope in the Shoulclero

I;''

Ph=ito T.-Iousin9 £or the temperature recording device.

Photo 9~ Interior of temperature recording installation. Recording potentio­;:neter above, two electrical heaters below.

Table 1 16

Physical Properties of Styrofoam Scorbord SM

ASTM Test Method l" Thick 2" Thick

Density a #/fto 3 2o7 2o3 Tensile Strength o pSio Dl623-59T 56 52 Ultimate Elongationo % Dl623-59T 2o3 2o5 Tensile Modulus, psio Dl~23=59T 2490 1990 Compressive Strength D 621~59T 31 48

at 5% Deformation 0 psio Compressive Moduluso psio Dl621~59T 876 1900 Flexural Strengtho psio C203~58 96 114 Deflection at Break 0 inc C203-58 Oo 57 Oo62 Flexural.Modulus 0 psio C203-58 3830 2750 Shear Strangtho psio C273-53 42 25 Shear Modulus, psio C273~53 652

1 0 Tensile properties were obtained at a crosshead spe.ed of Oo05"/ mine for 1 11 specimens and at Ool"/mino for 2°' specimens, using respectively l" and 2 °' jaw spano

2o Compressive properties were obtained at a crosshead speed of Ool 1Jfuino/ l'" of specimen thicknesso

3o Flexural properties obtained at a crosshead speed of Oo5n/mino for 1 11 specimens and loO"/mino for 2" specimens using a 10" spano

4o ·Shear properties obtained at Oa05"/mino crosshead speedo

TABLE 2

CENTERLINE PROFILE ELEVATION

Before Resurfacing After Resurfacing

Sta. Dec. '63 Feb. "64 May '64 'Dec. '64 Apr. '65 May '65

600+00 99.87

+33 B e g i n

+40 99.99

+60 100.15

+80 100.32

601+00 100.49

+20 100.63

+40 100.79

+60 +oo.93

+80 101.09

602+00 101.23

99.93 99.83

G r a n u 1 a r

100.05

100.17

100.35

100.51

100.64

100.80

100.95

101.13

101.27

101.39

99.97

100.12

100.31

100.48

100.62

100.78

100.92

101. 08

101.24

101. 36

100.08 100.15

B a c k f i 1 1

100.21

100.36

100.55

100.71

100.88

101.02

101.18

101.34

101.50

101.62

100.32

100.43

100.60

100.76

100.90

101.06

101. 21

101.36

101. 51

101. 64

100.07

100.23

100.38

100.57

100.73

100.88

101.03

101.27

101. 33

101. 48

101.62 +20 101.36

+33 tE n d

+40 101.47

G r a n u 1 a r - I e g i n S t y r c f o a m

+60 101.62

+80 101.76

603+00 101.92

+20 102.12

+40 102. 28 '

+60 102.44

+80 102.58

101.48

101.64

101. 78

101.95

102.14

102.30

102.46

101.47

101.62

101. 77

101. 93

102.11

102.28

102.44

101. 75

101.90

102.04

102.22

102.38

102.54

102.70

101. 75

101. 90

102.04

102.21

102.40

102.56

102.72

~02.60 ~02.58 102.85 to2.87 '--~--~+-~~~~L--~~~--''--

(Tab I e Continued On Next Page)

101.73

101. 88

102.03

102.21

102.38

102.55

102.71

102.85

17

., \,.

18

TABLE 2 (Continued)

CENTERLINE PROFILE ELEVATION

Before Resurfacing After Resurfacing

Sta. Dec. '63 Feb. '64 May '64 Dec '64 Apr. '65 May '65

604+00 102.73 102.74 102.73 102.98 103.02 102.99

+20 102.85 102,87 102.86 103.12 103.15 103.11

+40 103.00 103.02 103.00 103.25 103.30 103.26

+60 103.16 103.18 103.17 103.41 103.45 103.42

+80 103.34 103.37 103.34 103,60 103.65 103.63

+85 E n d s t y r o f o a m

605+00 103.56 103.66 103.55 103.80 103,88 103.80

+20 103.73 103.83 103.72 103.99 104.06 103.99

+40 103.92 103.99 103.90 104.18 104.24 104.18

606+00 104.50 104.58 104.49 104~76 104.81 104.78

Average Change Per Section

Dec. '63 Feb. '64 Dec "64 Apr" '65 to to to to

Section Feb. "64 May '64 Apr '65 May '65

Granblar +0.028' -0.038' +0.030' -0.029'

Styrofoam +0.020' -0.018' +0.019' -0,018'

Outside Test Section +0.082' -0.096' +0. 065 ! -0.059'

19 TABLE 3

SUBGRADE MOISTURE CONTENT

..

s t' a t i d h 6 0 1 + 0 0 ( N 0 s t y r 0 f 0 a m }

6 Ft. Lt. of CL 6 Ft. Rt. of CL 14 Ft~ Rt. of CL -· Under Slab Under Slab f n

-· Shoulder

Depth % Moisture % Moisture % Moisture

Inches Apr. "64 May '65 Apr. "64 May "65 Apr. '64 May '65

0- 6 5.7 6.9 4.7 7.0 21.0 17.7

6-12 4.6 4.1 5.1 5.8 10.0 13.4

12-18 4.5 3.5 4.2 4.2 6.0 5.9

18-24 5.1 4.9 --- 4.8 5.9 5.3

24-30 --- --- --- --- 6.7 6.6

30-36 --- --- ,,_,,_...., --- 7.9 7.6

s t a i i 0 n ( 0 2 + 0 0 ( N 0 s t y \,,

0 f 0 a rr )

0- 6 ,, ~ 7 1 6.2 5.8 5.9 14.0 12.6 _, . ,

I i 6-12 5.7 5.4 5.9 5.6 8.0 11.2 '

12-18 4.9 4.1 5.4 5.4 5.6 10.9

18-24 4.9 4.7 --- 5.6 5.3 5.2

24-30 --- --- --- --- 5.6 13.9

30-36 --- --- --- --- 7.1 9.4 ..

36--42 ·---- --- --- --- 11.2 6.6

-· I s t a t i 0 n 6 0 3 + ~~ . !

...,,J .I .... { s t y r 0 f ,:I> a m 0 n 1 y }

0- 6 10.0 13.5 ' 17.3 17.7 --- ---6-12 --- --- 15.0 14.7 18.5 20.5

12-19 --- --- 16.2 15.0 11. 9 15.5

(Table Continued On Next Page) . .

20

TABLE 3 (Continued)

SUBGRADE MOISTURE CONTENT

s t a t i 0 n 6 0 3 + 5 0 (S t y r 0 f 0 a m 0 n 1 y) (Cont.)

6 Ft. Lt. of CL 6 Ft. Rt. of CL 14 Ft. Rt. of CL Under Slab Under Slab ln Shoulder

-

Depth % Moisture % Moisture % Moisture

Inches Apr. '64 May "65 Apr. "64 May "65 Apr. '64 May "65

19-25 14.1 19.0 --- --- --- ---

25-31 --- --- --- --- 17.1 24.0

31-37 --- --- --- --- 20.4 21.9

37-43 --- --- --- --- 18.5 19.3

''

s t a t i 0 n 6 0 4 + 5 0 ( s t y r 0 f 0 a m 0 ri 1 y )

6 Ft. Rt. of CL 14 Ft. Rt. of CL Under Styrofoam In Shoulder

Depth % Moisture % Moist ure

U:nches Apr. "64 May "65 Apr. '64 May '65

\ 12.9 18.9 19.2 17.7 0- 6

! 6-12 17 ;9 17.8 16.9 17.5

k2-18 19.5 17.6 16.9 17.3 ' 1 I

'.18-24 17.3 --- 15.0 16.8 ''

,l

i24-30 --- --- 13.6 13.9

' ~0-36 . 13.4 13.2 --- ---. s t a i 0 n 6 0 2 + 5 0 (Styro:t: 8am and 4 mil pol ye hylene)

0- 6 10.4 14.4 --- ---

'6-12 14.4 14.4 --- ---

~2-18 15.2 14.7 --- ---(Table Continued On Next Page)

21

TABLE 3 (Continued)

SUB'GRADE MOISTURE CONTENT

s t a t i 0 n 6 0 2 + 9 0 (Styrofoam and 4 mil polyethylene)

6 Ft. Rt. of CL 14 Ft. Rt. of CL Under Styrofoam In Shoulder

Depth % Moisture % Moisture

Inches Apr. "64 May "65 Apr. "64 May "65

0- 6 14.6 15.0 --- ---6-12 16.7 16.2 --- ---

12-18 16.4 15.0 --- ---

s t a i 0 n 6 0 3 + 9 0 { s t y r 0 f 0 a m 0 r 1 y )

0- 6 14.6 15.5 --- ---

6-12 17.2 16.3 --- ---

12-18 15.7 14.7 --- ---

s t a i 0 n 6 0 4 + 2 0 ( s t y r 0 f 0 a m 0 r 1 y)

0- 6 14.8 19.2 --- ---6-12 19.2 17.5 --- ---

12-18 18.7 19.9 --- ---

N

l

C"l C"l + ' 0 0 l.O . tlj .µ

450'

0

ROW . . .

-0 l.O

Specie 1 ~

Backfill

-~

Thermocouple Group Thermocouple Wire

Line

Temperatu~a-----------~l ,,.-- I

Recorder · / I t // I I

/ I I /

I I / / I I

/ I / I / f

/ f I / f I

/ I I '. /

/ I I

/ I / q ___ -- _,/f /

/ */ d -- / ·~ ii -- _....,_-<_ - - - I ---- - ----4 Itl..il - - - - I ....... ' ..............

- -Polyethylene , ...... .......

0 .......

- ··-I--- -

..... "O

No Styrc

us #18_1~-bfoam l~" Styrofoam

I 2-3/4" f tyrofoam l~" Sty '"'ofoarn

0 0 + N 0

. \.0 . ro .µ CJ)

9" P.C. Concrete Pavement

Scale l"= 20' Vert. l"= 50' Horiz.

C"l co C"l 0 + -1 N C"l 0 0 l.O l.O . . ro nl .µ .µ CJ) CJ)

Figure 2

0 00 0 M 1..n 0 LO co + -L + + (""') ~ 'tj' 'tj' 0 0 0 0 l.O \.0 l.O l.O

. . . . ro nl fl:I m .µ .µ .µ ,·P·· CJ) CJ) CJ) CJ)

..

. ' ~

N N

0 Thermocouple (Regular Recording)

ag Thermocouple (Alternate Recording)

Scale

l" = 4' horiz.

l" = 10 11 vert.

/O '

3'

~ ~ e '11\J

'\f-~ Ci

0

" "9 0+ I

" @·

\:J ........

@l_

Thermocouple Locations

Sta. 602+00

/Z; >I //; I

9 II P.C. Cone. Pav't. ~

0)

0

0 ~

"ti-

~ 0

• Q)

t 0

'9 ~ "'!-~

0

~

(\j ........

J_ 0

Figure 3

0 'rli.ermocouple (Regular Recording}

~ Thermocouple (Alternate Recording)

Scale

l" = 4' horizo

l" = 10" verto

12.'

1 9 11 PoCo

0 ~-+---

'------+- l~ '' Styrofoam

<!>--- t

Thermocouple Locations

Stao 604+50

Figure 4

Thermocouple (Regular Recording)

Scale:

1" = 4 1 Horizontal 1" = 10" Vertical

/2. I

11'1 J 11 A. C. Surfacing

911 P. C. Concrete ~ ......

0

0

I 10 ~

'-0

+0 '> (\} ......

+0 ,,,. (\j .......

__L~

Figure 5: Thermocouple Locations Sta. 602 + 00 - Effective 5-7-65

ct

~

°" '\}-

e T!1ermocouple (Regular Recording)

Scale:

111 = 4 1 Horizontal 1" = 1011 Vertical

.. ~,__ _____ / 0 / /2. I

'6'/ 14----- 7- --~E------

311 A. C. Surfacing

9 11 P. Co Concrete

Styrofoam

Figure 6~ Thermoeouple Locations Sta. 604 + 50 = Effe-, ':-ive 5=7=65

__j_ --0

0

l I

<P

I

rt

~ '\;)-.. .........

4 """ ~ ;:,

~ "' (X)

~

-t '>

[\j .....__

60

50

.µ ·r-1 40. Q)

.g (]}

H 30 ~ Iii

(I) 20 Q) Q) H tJ"I Q) 10 Cl

0

10

10 20 NOVo

30

1963

Average Daily Air Temperature

___ _]~--------

10 20 30 Dec.

9 19 Jana

Figure 7

29 8 18 Febo

28

1964

9 19 Mare

29 8 18 April

60

50 +> •rl Q)

..c ~ Li-O (!)

~I _,_~

' " ClJ

µ,. -- -UJ '30 Q) Q)

H b0 O,l :? 'J ~

10

']

-10

1 () 2.0 'I 1' ..l..•.'

Nev. 20 Q 1~

Jan.

{\/

8 lO ::i:i Feb.

1of,r: "" ....

10 20 JO ·Lar.

9 10 ~,,

-t'Lpr ...

{\) (;J

J

60

50

40

30

20

10

0

10

Average Daily Temperature

8" below the Surface l" above the Styrofoam

..'..___ --- _Q':._ - --

10 20 30 10 20 30 Novo Deco

1963

9 19 Jan.

Figure

--------------------

29 8

9

11~ 11 below the Surface l" below the Styrofoam

18 28 9 19 29 Febo Maro

1964

I 8 18 April

N

'°

Average Da4ly Temperature

50 14t" Below A~ C~ Surface (1" Below Styrofoc")

Below A. C. Surface ( 11! Above Styrofoam)

40

/

-f -- - - - --,

30 ::

( +:> ·rl Q)

..c:

\ s:: (!)

H 20 ..c: I ell J::r_,

Cl)

~ <D Q)

H till 10 Q)

~

v~ 0 OQ _,_,_. __ - - - - -·--- -- - - - - --

-201----1------'--------'-------'-------1"------.L-----L------L.-----1..----1-----..J_------1 1 11 21 31 10 20 JO 9 19 - 11

December 1964 January 1965 Fetc•1~~ry March

Fig1J.re 10 \._;. ~

40

30

20

10 +' ·rl Q)

·c§ Q)

11 C1}

i:r..

--~

_,.,q_ / \ /

-10_

=20

'

\

\ \

\

\

\

Qf-------"'O

0---- - -0

\_ - ---z1

"-.._

Minimum Air Temperature

Minimum Concrete Temperature 8" Below P. C. Surface (No Styrofoam)

Minimum Concrete Temperature 8 11 Below P. C. Surface (1 11 Above Styrofoam)

(P. C. Concrete is 9 in. thick)

;A, I \ \

1 ', ~ \ ''\

~-~ _j ' ~-~,

I I

b-_ -~

\

'

' \ \

\ \

~ " ' '

=30 ~1Q~.~~~--:-1~2~~-t--~~1~4~~+-~-1~6~~1--~-1~2~~-'--~-2~0~~1-~-2L2~~l-~-2~4~~1--~-2~6~~'--~-2~8~~1-~J~0

December 1963 Figure 11: Concrete temperatures as J.ffe-· L':'!d cw ins'.J.lation - Winter 1963

.,_, ·rl Q)

40

JO

20

"§ JO Q)

.E CIS

fr.. U) (1) Q)

~

Il' o n

=10

~20

=30 12

'

\ \

O'------__,o

o--------0

\

\ '\ /

\/ f

I

14 J.6

Minimum Air Temperature

Minimum Concrete Tem.perd.ure 11 n Below A. C. Surface (No Styrofoam)

Minimim Concrete 'I'ernpe~~ature 11" Below A. C. Surface (1n Above Styrofoam)

(P. Co Concrete is 9 in. thick= Asphalt overlay is Jin.)

'

\

18 20 22 24 26 28 JO January 1965

/ \

/

1

\ \ o.---er-

J 5 F'ebrucry 1965

Figcre 12: ConcreL0 - ci,lJr_"':''c "' affected by in~3U1ation - Winter 1964 - 1965

6

120

110

-P100 ·rl GJ

.. r:::..'

§ ~~I

..d cu

""-· {/)

CJ) 90 CJ)

H OD Q)

~

e.o

70

60

v

15

/ /

o a

er -- - - - --o

ff

17

/ /

I 19

\

Maximum Air Temperature

Maximum Concrete Temperature 11 11 Below A. C. Surface (No Styrofoam)

Maximum Concrete Temperature 11 11 Below A. C. Surface (1" Above Styrofoam)

(P. C. ConcPete is 9 in. thick - Asphalt overlay is J in.)

I

I 21 23 25 27 29 J1

.July 1964

Figure 1J: Concrete temperatures as affected by insulation - Summer 1964 ----

/ /

/

2 August

/ /

'\ /

'd

1964 I....) I....)

4

110

/

100

o----~o

0-------o

' '

Maximum Air Temperature

Maximum Concrete Temperature 11 rt Below A. C, Surface (No Styrofoam)

Maximum Concrete Temperature 11'1 Below A. C. Surface (1 11 Above Styrofoam)

(P. C. Concrete is 9 in. thick - Asphalt overlay is J in.)

9

o---.(f I

11

Figure 14: Concrete temperatures as affeeted by insulation - Sv":mer 1965

P- -/

/ f'

/ /

13

35

~ 11 ~ Air (-26) -.,.j 11 ~ 0

0

(-19) I

5 - 9"· P. C. Concrete c-f7) I P. C. Concrete 911

! l 0 Cl

(-15 -1) 10 - 11-11 Styrofoam 2 0

t 0 ' (J) (34)

15 -0

( 7) . 0 >:: (35) .,;

Q) 0 20 -<U

'+-i H ;::S

Cl) 0

' (13) 0 0 . 25 - (37) A.+

::;: 0 rl

Q) µ::)

Q) 0 ~o >:: ) -cU

+> (/)

.,; A

35 0

0 (24) (38)

40

0

(27)

50_

Figure 15: Minimum Temperatures OF - November 1963 - June 1964

,-.~ , ~' ,/ .•...

~1'r Air (-25) ~1·~ 0 t

Y' A. C. Surf acing A. c. Surfacing " ( 0

5- (-11)

911 P. c. Concrete 0 P. ,., Concrete 911 v,

t !- \

l l \ _,,-, ,:

10_

0 0

(-8) 2) 1t11 Styrofoam 0

15_ 0 (5)

(JO)

0

0 (7)

d 20.._ (Ji) ·rl

(}) u C1l

4-1

~ 25- 0 Cf)

(12) • 0

0 ( 33)

' <.'~

~ 0 30_ r-~ Q)

(ll

<]) ()

r.:: m ~ 35_ ·rl A

0

0 ( 19)

L~O _ (36)

50_ 0 (26)

Figure 16: JVIinimum Temperatures °F November 1964 - May 1965

37

~1i~ Air (99) ~1~~

0 <t:. rt. 1'

I 3" A, Co Surfacing A. C" Surfacing Y'

5 0 - (117)

Po Co Concrete Po Co Concrete 9" 0 911 ( 114) I 10

0 0

11-11 Styrofoam 0

1 c: 0 ( 100)

_; . ( 71_~) s:: ·rl

0

CD 0 (97)

0 (72) ~ 20

s U)

0

0

0

< 25 - 0

6 (94) r--1 0

CD (70) co

CD C.J s:: 30 -m

+> U)

·rl i::i

35 -

0

0 (87)

40 (67)

45 _

0 50 - (84)

Figure 17~ Maximum Temperatures CF - June 1964 - November 1964

38

~1u~ Air (96) ~1u!< 7u~6RU >I 0

<f t 0 0

311 A. C. Surfacing (128)1 Ao Co Surfacing (12J) 3 11

I (1j5)1 5_

(113) ( 110)

9" P. Co Concrete P, C. Concrete Q II /

10-0 0

11-n 2 Styrofoam 0

15_ 0 (92)

. (69) >::: ·rl

0

(lJ 0 (89)

{)

(69) ctj 20_ 4-1 s U)

0

0

0

c::i: 25_ 0 :;: (86) 0 rl Q Q) (67) p.:; Q) u

JO_ >::: Cl)_

+:> [I)

·rl ~

35

0

0 (81)

40 (65)

0 50_ (78)

Figure 18: Maximum Temperatures PF - May 1965 =August 1965

+400

l't.i 0 N ("\

CJ) :> =400 0

..0 <

(/)

» -600 ~

Q) =800 Q)

~ b.D CJ)

~ =1000 CJ)

:> orl .+-) C\l

r-1 =1200 § ;:j ()

-1400

=1600 I< 1JO Days

-18QO 10 20 30 10 20 30 9 19 29

Deco Jana

Figure 19~ Determination of Freezing Index

8 18 28 Feb~

1964

9 19 Mar.

~I

29 8 18 Apro

l:!:...1

0 N (""'\

Q)

:> 0

~ Ul p., m

Q

(j) <D ~. hO Q)

~

Q)

::> or/ +) rn rl § :::l

0

+400

+200

0 -

=200

=400 -

-600

=800

-1000 -

=1200

=1400

=1600

10 20 Nov.

30

1964

10 20 JO Deco

Figure 20~ Determination of Freezing Index

133 Days

9 19 Jano

29 8 18 Febo

28 10 20 Maro

1965

30 9 19 Apr.

o II

10 ....

50 -

II

111111

or Less

I

I ' I I

~ 1 I I I I Pi i I

l I Above J2° F

I

10 20 JO

1963

Figure 21:. Depth at ,fbich avei

I

9 i9 _. ;_.:~ '. i r;>

I I I I ?O ~/ 18 28 9 19

Feb~ Maro 1964

/ I

. I

I

29

I I ~

- I -

-I

8 18 Apro

0 ii II I I

II l Ill II I II I I I I

'"- ~ e ( Ir ~~e -

I ..... ii-ii Styrofoam -10

- --- -

15 ~ ~

- -

'"-- -

~ -

- -

L- -

45 1-- 11111 l I I -32° F Above

or 32° F Less -~ 50

I r I I I i ! ! I I l l I I . I I 10 20 30 10 20 :w

Nov. 1963 Dec" ·.

9 :l.9 29 8 18 ~'.~ar., A.pr~

Figure 22: Depth at ·:-v11J_c1:1 avero.ge temy.H::.:···~1

,_l 5~ § 8 ID

~ JO~ fl.

;s 0

'6 J5~ p::i

QJ

u @ r-0 -~~

+> !fl

•rl i::'.l

45_

50 _

111111 J2<l' F

or Less

I I

I I Above 32° F

I I I I

10 20 JO iC 20 JO Nov~ Dec.

-I ' I i I I l I

9 19 29 8 18 28 10 20 30 9 19 Jan. F~eb~ Mar .. l Apr~

1965

F~~c6ure 23 ~ Depth at which average tem:r)eratures of J2° F or less were recorded

J

" II I II I

c: '-

LO " s::

- 11 ·rl

(!) 15 .__

0 ctl ~ H 20 ;j

U) '-

+:> s:: Q)

s 25 Q) '-p. Qj

p..

~ 30 ,_ rl

Q)

r:r:l Q) 35 0 -c cU

+:> (/)

·rl 40 Q -111111 I I

45 J2° F Above '---

J2° F or Less

50 -I I I I I

10 20 30 10 20 Nov. Dec.

1964

Figure Depth at which av,o;::·s.gc

II I I Ii r ~ hg .J

~ ~

i. t:; I>

'11 :i.t11 Styrofoam

I I I I I ':. (! q ·, ,,

...... ;i q ·~-

l.farl.,.

I 1 p .J.. '~)

I II

I

}i'eb~

I 28

1111 11111

I

10 I

20 Mar.

1111 II

-

-

-

-

-

-

-

-

-

-

I I 30 9 19

Apr.

J