report of pavement evaluation services

Report of Pavement Evaluation Services 8th Street NW & McMillan Street NW Georgia Institute of Technology Atlanta, Georgia Geo-Hydro Project Number 170848.2

Prepared for Breedlove Land Planning, Inc. October 12, 2017

1000 Cobb Place Boulevard, Suite 290 • Kennesaw, Georgia 30144 o: 770.426.7100 • f: 770.426.5209 • www.geohydro.com

Mr. Alan Wieczynski, RLA, LEED AP BD+C October 12, 2017

Breedlove Land Planning, Inc.

15 Simpson Street NW

Atlanta, Georgia 30308

Report of Pavement Evaluation Services

8th Street NW & McMillan Street NW

Georgia Institute of Technology

Atlanta, Georgia

Geo-Hydro Project Number 170848.2

Dear Mr. Wieczynski:

Geo-Hydro Engineers, Inc. has completed the authorized subsurface exploration for the above referenced

site. The scope of services for this project was outlined in our proposal number 20887.2 dated

August 24, 2017.

The purpose of this exploration was to determine the thickness of the pavement section along 8th Street NW

between Hemphill Avenue NW and Curran Street NW, and along McMillan Street NW between 9th Street

NW and Turner Place NW, in Atlanta, Georgia.

We understand that you will use the subsurface information to develop design and construction documents

for the programed repaving of 8th Street and McMillan Street. The following sections provide information

regarding our exploration procedures and the results of the soil test borings. The aerial photo below

illustrates the overall extent of the project and test locations.

8th Street NW & McMillan Street NW - Georgia Institute of Technology Atlanta, Georgia Project Number 170848.2

October 12, 2017 | 2

Exploratory Procedures

The subsurface exploration consisted of 10 hand auger borings performed at the approximate locations

indicated on Figure 2 in the Appendix. The borings were located in the field by Geo-Hydro by measuring

angles and distances from site features. In general, the boring locations should be considered approximate.

To provide access to the subsurface, the existing pavement was cored using a 6-inch diameter core barrel.

Starting at the soil subgrade, dynamic cone penetrometer testing, as provided for in ASTM STP-399, was

performed at select depth intervals in the borings. Soil samples obtained from the borings were examined

and classified in general accordance with ASTM D2488 (Visual-Manual Procedure for Description of

Soils). Soil classifications include the use of the Unified Soil Classification System described in ASTM

D2487 (Classification of Soils for Engineering Purposes). The soil classifications also include our

evaluation of the geologic origin of the soils. Evaluations of geologic origin are based on our experience

and interpretation and may be subject to some degree of error.

Descriptions of the soils and subsurface conditions encountered are present in the hand auger logs included

in the Appendix. Groundwater conditions, dynamic cone penetration resistances, and other pertinent

information are also included.

Laboratory Testing

Samples for laboratory testing related to the moisture of the soils were obtained from the auger cuttings at

four boring locations. Moisture content tests (ASTM D2216) were performed on select samples obtained

during the exploration.

Hand Auger Boring Summary

Starting at the ground surface, borings B-1 through B-5 (8th Street), encountered pavement materials

consisting of 5¼ to 8½ inches of asphalt pavement underlain by ¾ to 5¾ inches of graded aggregate base.

Borings B-6 through B-10 (McMillan Street) encountered pavement materials consisted of approximately 1¼

to 8½ inches of asphalt. Immediately beneath the asphalt, borings B-6, B-7 and B-8 encountered concrete

ranging in thickness from 4¼ to 5½ inches. Boring B-9 encountered 6 inches of crushed aggregate base

and B-10 did not encounter any crushed stone base. Borings B-2, B-3, B-5, and B-9 encountered auger

refusal just beneath the pavement materials.

Beneath the pavement materials, borings B-1, B-4, B-6, B-7 and B-8 encountered fill materials extending

to depths ranging from about 3 inches to greater than 3 feet. Borings B-1, B-4, and B-6 were terminated at

depths between 3 inches and 3 feet, without fully penetrating the fill materials. Dynamic cone penetrometer

resistances recorded in the fill ranged from 4 to greater than 25 blows per increment.

Beneath the pavement or fill materials, borings B-7 and B-10 encountered residual soil typical of the

Piedmont Region. The residual soils were classified as silty sand. Dynamic cone penetrometer resistances

recorded in the residual soils were 8 and 18 blows per increment.


October 12, 2017 | 3

No groundwater was encountered in the hand auger borings. The borings were backfilled with soil cuttings

upon completion and patched with asphalt. It should be noted that groundwater levels will fluctuate

depending on yearly and seasonal rainfall variations and other factors, and may rise in the future. Perched

groundwater will be highly variable, as its presence will be predominately a function of recent rainfall.

For more detailed descriptions of subsurface soil conditions, please refer to the hand auger logs included in

the Appendix.

Boring

Asphalt Thickness (inches)

Concrete Thickness (Inches)

Crushed Stone Thickness (inches)

Bottom of Fill (feet)

Depth to Groundwater

(feet)

Boring Termination Depth (feet)

Natural Moisture

Content (%)

B-1 5¼ NE 5¾ ¼ NE 1¼* 17.2

B-2 7¾ NE ¾ NE NE ¾*

B-3 8½ NE 1½ NE NE 1¼*

B-4 8 NE 2 >3 NE 3 17.9

B-5 6 NE 2 NE NE 2/3*

B-6 1¼ 5½ NE >3 NE 3

B-7 1½ 5¼ NE 2 NE 3

B-8 2½ 4¼ NE >2½ NE 2½* 15.5

B-9 6¾ NE 6 NE NE 1*

B-10 8½ NE NE NE NE 3 19.4

All Depths in this Summary Table are Approximate NE: Not Encountered N/A: Auger refusal without fully penetrating GAB *: Auger Refusal

Evaluations and Recommendations

The following evaluations and recommendations are based on the information available on the proposed

construction, the data obtained from the hand auger borings, and our experience with soils and subsurface

conditions similar to those encountered at this site. Because the hand auger borings represent a statistically

small sampling of subsurface conditions, it is possible that conditions may be encountered during

construction that are substantially different from those indicated by the boring. In these instances,

adjustments to the design and construction may be necessary.

The thickness of the asphaltic concrete encountered in the borings ranged from 1¼ to 8½ inches. Visually,

the existing pavement shows signs of environmental cracking related to age. The thickness of the crushed

stone base beneath the asphalt ranged from about ¾ to 5¾ inches. A section of Mc Millan Street as

represented by borings B-6 through B-9 consists of concrete pavement with an asphalt overlay.

The most widely observed types of pavement distress consisted of low severity weathering and low to

medium severity block cracking, alligator cracking, and longitudinal/transverse cracking. It is our opinion

that the pavement distress observed throughout the project is not due to a lack of structural capacity but

mostly a function of a wearing course that has reached its design life. There are localized pavement distress

areas that appear to be related to the installation of underground utilities and possibly other localized

deficiencies of the pavement structure itself. Additionally, some of the cracks and distress in the


October 12, 2017 | 4

asphalt-over-concrete section of McMillan Street may be the result reflective cracking through the asphalt

overlay.

Overall, the underlying subgrade appears to be stable and relatively uniform. It is our opinion that milling

and overlaying would be the best approach to rejuvenate and extend the service life of the pavement. The

following photos illustrate the pavement conditions observed throughout the limits of this evaluation.

Mill and Overlay

It is our opinion that the most appropriate way to rejuvenate and extend the life of the pavement is to

implement a functional mill and overlay approach. We recommend a mill and overlay scope consisting of

milling 2 inches of existing asphalt pavement and replacing the milled section with 2 inches of 12.5 mm

Superpave wearing course. In asphalt-over-concrete sections of McMillan Street, the existing asphalt

overlay is less than 2 inches thick. All the asphalt in these sections should be removed and replaced with a

2-inch thick overlay of 12.5 mm Superpave wearing course.

Existing environmental block cracks will need to be sealed prior to the milling process. Any isolated areas

of alligator cracking that may be identified should be repaired prior to milling. Repair should consist of

removal of existing asphaltic concrete pavement, leveling and recompaction of the crushed stone base, and

placing asphaltic concrete base up to the original pavement elevation. Once the necessary crack sealing

and spot repairs have been completed, the existing asphalt can be milled to the prescribed depth. Any areas

of distress identified after milling should be repaired as necessary.

Where present, existing environmental block cracks and cracks in the underlying concrete (McMillan

Street) are likely to reflect through the overlay layer and such reflective cracking may occur within a period

of about 5 years, possibly sooner. The detrimental effects of reflective cracking can be limited by

performing routine maintenance consisting of crack sealing. There are reflective crack control methods

and products such as a chip seal layer, Perma Flex®, and various geosynthetic products that can be applied

to retard the propagation of reflective cracking. In our opinion, given the size of the project and the current

pavement conditions, treatment of existing environmental pavement cracks beyond pre-mill sealing does

not appear necessary. Nevertheless, options to intervene more aggressively to reduce the likelihood of

reflective cracking are available and may be implemented depending on Georgia Tech’s or the City of

Atlanta pavement management approach and asset management philosophy.


October 12, 2017 | 5

We appreciate the opportunity to serve as your geotechnical consultant for this project, and are prepared to

provide any additional services you may require. If you have any questions concerning this report or any

of our services, please call us.

Sincerely,

GEO-HYDRO ENGINEERS, INC.

Emily Mille, E.I.T. Luis E. Babler, P.E.

Staff Engineer Chief Engineer [email protected] [email protected]

BKI/LEB/170848.2 Pavement Eval 8th & McMillan - Georgia Tech - Atlanta, GA.docx

APPENDIX

Figure 1: Site Location Plan

Approximate Scale, Miles

0 0.25 0.5 1 1.5



Atlanta, Georgia


B-1

B-2

B-3

B-6

B-9

B-10

B-4

B-5

B-7

B-8

Figure 2: Boring Location PlanLEGEND: Soil Test Boring



Atlanta, Georgia


0

Approximate Scale: 1"= 100'

50 100 200 300

Symbols and Nomenclature Symbols ▐ Thin-walled tube (TWT) sample recovered

Thin-walled tube (TWT) sample not recovered

● Standard penetration resistance (ASTM D1586)

50/2” Number of blows (50) to drive the split-spoon a number of inches (2)

65% Percentage of rock core recovered

RQD Rock quality designation - % of recovered core sample which is 4 or more inches long

GW Groundwater

Water level at least 24 hours after drilling

Water level one hour or less after drilling

ALLUV Alluvium

TOP Topsoil

PM Pavement Materials

CONC Concrete

FILL Fill Material

RES Residual Soil

PWR Partially Weathered Rock

SPT Standard Penetration Testing Penetration Resistance Results Approximate Number of Blows, N Relative Density Sands 0-4 very loose

5-10 loose 11-20 firm 21-30 very firm 31-50 dense Over 50 very dense

Approximate Number of Blows, N Consistency Silts and 0-1 very soft Clays 2-4 soft 5-8 firm 9-15 stiff 16-30 very stiff 31-50 hard Over 50 very hard Drilling Procedures Soil sampling and standard penetration testing performed in accordance with ASTM D 1586. The standard penetration resistance is the number of blows of a 140-pound hammer falling 30 inches to drive a 2-inch O.D., 1.4-inch I.D. split-spoon sampler one foot. Rock coring is performed in accordance with ASTM D 2113. Thin-walled tube sampling is performed in accordance with ASTM D 1587.

6

Asphalt (Approximately 5-1/4 inches)

Crushed Stone Base(Approximately 5-3/4 inches)Red-brown and gray clayey fine to coarse sand (SC) with rockfragments (FILL)Auger Refusal at 1'- 2" on large rocks

No Groundwater Encountered

1

2

3

4

GR

AP

HIC

LO

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DE

PT

H(f

eet)

LA

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ES

TS

DR

Y U

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WT

. (pc

f)

Elevation(ft):

Penetration resistance was evaluated in accordance with ASTM STP-399.The penetration resistance is the number of blows of a hammer weighing15 lbs. falling 20 inches to drive a 1.5 inch diameter cone 1.75 inches.

MATERIAL DESCRIPTION MO

IST

UR

EC

ON

TE

NT

(

%)

PE

N.

RE

SIS

T

Equipment: Hand Auger

Date Performed: 9/29/17 Logged by: KD

SA

MPL

E

HAND AUGER LOG B-01

8th Street NW & McMillan StreetGeorgia Institute of Technology - Atlanta, Georgia

170848.20

HA

ND

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GE

R H

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BO

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.GP

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N07

.GD

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0/12

/17

14


Crushed Stone Base(Approximately 3/4 inch)Auger Refusal at 8-1/2" on large rocks cemented in place. Possiblyanother layer of asphalt or concrete.


1

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4

GR

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IST

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%)

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SA

MPL

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HAND AUGER LOG B-02

>25


Crushed Stone Base(Approximately 1-1/2 inches)Auger Refusal at 1'-2" on large rocks


1

2

3

4

GR

AP

HIC

LO

G

DE

PT

H(f

eet)

LA

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. (pc

f)

Elevation(ft):



IST

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%)

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SA

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HAND AUGER LOG B-03


170848.20

HA

ND

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AN

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BO

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.GP

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0/12

/17 6

8

Asphalt (Approximately 8 inches)

Crushed Stone Base(Approximately 2 inches)Red-brown and gray clayey fine to coarse sand (SC) with rockfragments (FILL)

Boring Terminatedat 3 feet.


1

2

3

4

GR

AP

HIC

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PT

H(f

eet)

LA

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. (pc

f)

Elevation(ft):


IST

UR

EC

ON

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NT

(

%)

PE

N.

RE

SIS

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SA

MPL

E

HAND AUGER LOG B-04

>25

Asphalt (Approximately 6 inches)

Crushed Stone Base(Approximately 2 inches)Auger Refusal at 8" on large rocks


1

2

3

4

GR

AP

HIC

LO

G

DE

PT

H(f

eet)

LA

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ES

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DR

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. (pc

f)

Elevation(ft):



IST

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ON

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(

%)

PE

N.

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SA

MPL

E

HAND AUGER LOG B-05


170848.20

HA

ND

AU

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R H

AN

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BO

RIN

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.GD

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0/12

/17

4

Asphalt (Approximately 1-1/4 inches)Concrete (Approximately 5-1/2 inches)Brown silty fine sand (SM) with rock fragments (FILL)

Boring Terminated at 3 feet


1

2

3

4

GR

AP

HIC

LO

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DE

PT

H(f

eet)

LA

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. (pc

f)

Elevation(ft):


IST

UR

EC

ON

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NT

(

%)

PE

N.

RE

SIS

T


Date Performed: 9/28/17 Logged by: EM

SA

MPL

E

HAND AUGER LOG B-06

>25

18

Asphalt (Approximately 1-1/2 inches)Concrete (Approximately 5-1/4 inches)Brown clayey fine sand (SC) (FILL)

Tan silty fine sand (SM) (RESIDUUM)

Boring Termianted at 3 feet


1

2

3

4

GR

AP

HIC

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H(f

eet)

LA

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. (pc

f)

Elevation(ft):



IST

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ON

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(

%)

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SA

MPL

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HAND AUGER LOG B-07


170848.20

HA

ND

AU

GE

R H

AN

D A

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BO

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J L

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A G

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.GD

T 1

0/12

/17

11

Asphalt (Approximately 2-1/2 inches)Concrete (Approximately 4-1/4 inches)Brown fine sandy clay (CL) with rock fragments (FILL)

Auger Refusal at 2 1/2 feet on large rocks


1

2

3

4

GR

AP

HIC

LO

G

DE

PT

H(f

eet)

LA

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. (pc

f)

Elevation(ft):


IST

UR

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ON

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(

%)

PE

N.

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SA

MPL

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HAND AUGER LOG B-08

>25


Crushed Stone Base(Approximately 6 inches)Auger Refusal at 1 foot on large rocks


1

2

3

4

GR

AP

HIC

LO

G

DE

PT

H(f

eet)

LA

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. (pc

f)

Elevation(ft):



IST

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ON

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(

%)

PE

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SA

MPL

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HAND AUGER LOG B-09


170848.20

HA

ND

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BO

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0/12

/17 8

8


Pink slightly micaceous silty fine sand (SM) (RESIDUUM)

Boring Terminated at 3 feet


1

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GR

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SA

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HAND AUGER LOG B-10

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