Pavement_Memo.pdf

Page 1 of 25 Pages

Form FHWA-201 (Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

SUBJECT: Preliminary Pavement Recommendation for NP-CHCH 10(2), 14(1)

TO MESSAGE/COMMENT FROM/DATE

S.

Hailegiorgis PS&E Project Manager

And:

J. Johnson Highway Design Manager

Through:

S. Siou Highway Design Engineer

To support developing 30% PS&E for the project, we’re submitting our findings and preliminary pavement recommendations for the project NP-CHCH 10(2), 14(1). The project site is located in Chickamauga and Chattanooga National Military Park in Catoosa and Walker Counties, GA. The project consists of the resurfacing and rehabilitation of two park routes (~2.9 miles) and adjacent pull-offs and parking areas. Please note that upon completion of further analyses, this preliminary recommendation is subjected to change; and the changes will be included in the pending pavement report.

EXECUTIVE SUMMARY

Based on our field investigation on October 18, 2016 through October 21, 2016, we are providing the following recommendations:

McFarland Gap Road (Route 10) – Mill/remove the existing Asphalt Concrete (AC) pavement to the underlying concrete pavement (PCC). The PCC joints should be blown clean and re-sealed, the existing concrete pavement should then be overlaid with paving fabric, 4-inches of aggregate base placed, and capped with 3-inches of hot asphalt concrete pavement (HACP).

Mullis Vittetoe Parking Area (Route 900) and Mullis Rd Parking Area (Route 901) – Transition mill the existing AC surface course to a depth of 2-inches. The milled surface should be overlaid with 2-inches of AC pavement.

Reeds Bridge Road (Route 14) – Mill the existing AC to a depth of 2 ½-inches and overlay with Section 403 HACP -- Stress Absorbing Membrane Interlayer (SAMI). SAMI can be either double chip seal or Section 403 HACP. Cap the SAMI with 2-inches of HACP. Saw cut and seal the HACP above the existing transverse PCC joints.

Reeds Bridge Picnic Area Parking (Route 953), Reeds Bridge Road Parking Area (Route 0903), Brannans Division Monument Parking Area (Route 0904), Illinois Parking Area (Route 0905) – Remove the existing AC pavement. The existing aggregate base should be scarified and re-graded, and overlaid with 2-inches of HACP.

Jays Mill Road (Route 100) and Confederate Creek Crossing Parking Area (Route 921) – Remove the existing AC, scarify and re-grade the existing aggregate base/sub-grade, and overlay with 3-inches of HACP.

S. Deppmeier Pavement Engineer

Through:

S. O’Brien Pavement Team Leader

Through:

S.

Whittemore Technical Services Engineer

12/6/2016

STEPHEN P

DEPPMEIER

Digitally signed by STEPHEN P

DEPPME ER

DN c=US o=U S Government ou=DOT FHWASterl ngVA ou=FHWA FHWASterl ngVA cn=STEPHEN P DEPPMEIER Date 2016 12 06 12 35 59 05'00'

SEAN E

OBRIEN

Digitally s gned by SEAN E OBR EN DN c=US o=U S Government ou=DOT FHWASterl ngVA ou=FHWA FHWASterl ngVA cn=SEAN E OBR EN Date 2016 12 06 13 00 26 05 00'

Page 2 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

McFarland Gap Road (Route 10)

McFarland Gap Road is comprised of a composite pavement consisting of AC pavement over 6-inches of jointed PCC base. The existing AC thickness ranged from 4 ½ to 10 ¼ –inches, with an average of 6-inches (excluding the two AC thicknesses of 9-inches and 10 ¼ -inches at milepost 0.3).

The existing AC pavements are in poor condition with unacceptable ride quality, particularly above the underlying transverse PCC joints. AC stripping and de-bonding was encountered in a majority of the pavement cores, and at the 4 core locations above PCC joints. Attached are photos of existing conditions and of cores and their locations.

Seven of the nine PCC cores taken were found to be in good condition. As noted, 4 PCC cores were taken centered on the PCC joints, with 2 of the PCC cores being in good condition. The third core’s bottom portion below the reinforcing steel bar was broken off into gravel size pieces. The fourth core was in three pieces. The field investigation noted 67 PCC joints that had reflected up through the existing AC creating potholes and high severity joint deterioration leading to ride issues.

No PCC was found from the Park Boundary to 342 feet (Core C5) east of the Park Boundary. At the Park City intersection, no PCC was found in the eastbound (EB) through lane (Core C9). PCC was present in the westbound (WB) through lane (Core C12 and Boring B2 at the PCC joint). It is assumed that no PCC is present at the WB right turn lane and assumed that the PCC is present only in the WB through lane and the WB left turn lane (double yellow median) to Route 901 Mullis Road Parking.

We are providing several rehabilitation options below. Associated cost estimates include only the paving items for comparison purposes only, and are not of engineering estimate quality. All PCC joints should, at a minimum, be blown clean and sealed. A contingency for Full-depth PCC joint repair has been added to the rehabilitation options below.

All options will provide a satisfactory level of service upon completion of construction for the life expectancies provided. Reflective cracking should be expected with HACP overlays. Reflective cracking will propagate through the HACP at a rate of about one year for every one-inch of HACP overlay.

Therefore, with a 7-inch HACP overlay the first reflective cracking will occur roughly in year 7 after the HACP overlay is placed. For this reason we have presented the options below with a contingency to repair 5 to 10 PCC joints (as noted), and to clean and seal the remaining joints. This approach will help to mitigate working PCC joint cracks and reduce or retard reflective cracking.

Page 4 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Grade decrease is 1 ½-inch.

Life expectancy is 15 to 20-years.

Cost comparison value of paving items only is .

This option assumes that 10 PCC joints will need full-depth patching as per Table 7.

The cost comparison includes partial depth AC patching due to debonding or stripping AC below the 4-inch milling depth. This quantity is assumed 10% of the paving area. In addition, it includes a quantity for AC repair at the PCC joints, 3-feet long x 22 feet roadway width down to the PCC.

Option 1 does not address the practicality or constructability of keeping the roadways open during PCC joint patching. A risk is that more than 10% area of the underlying AC is debonding or stripping or needs removal for other reasons, giving this option the potential to increase in cost more so compared to other options.

The SAMI will retard reflective cracking but the roadway may still suffer reflective cracking in a few years. The remaining AC during construction may bridge failing PCC or even failing AC thus resulting in additional future repairs and future maintenance costs (see picture 5).

A variation of this option reduces the milling depth to 2 ½-inches, but the 10% area of partial depth patching should then be increased.

Option 2: Inverted Pavement

Option 2 consists of the use of an inverted pavement structure. The existing AC pavement should be removed down to the existing PCC surface. The PCC joints should be blown clean and sealed. A paving geotextile is placed, 4-inches of aggregate base course is placed and compacted, and then paved with 3-inches of AC pavement according to the minimum requirements laid out below in Table 2.

Page 16 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Discussion

Many options have been presented. Generally an idea or step in one option can be used to modify another option per the concurrence of the cross functional team.

The Design Scoping Report lists Schedule A as Reeds Bridge Road and Schedule B as McFarland Gap Road. If costs become an issue, Schedule B for McFarland Gap Road should be the PCC joint repairs. Schedule C can then be created for treating the surfacing wearing course via the options presented above. Schedule B has to be awarded before Schedule C. Any treatment of McFarland Gap Road without correcting the PCC joints will be a short term fix despite the cost associated with a long term fix.

The cost comparison presented in the options are not bid quality nor engineering estimate quality but merely represent a comparison between the options based on the CHCH 11(1) values.

Page 17 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Appendix A – Photos of McFarland Gap Road

Photograph 1– McFarland Gap Road, showing typical high severity block cracking and reflective cracking with delamination of HACP.

Photograph 2– McFarland Gap Road, showing typical high severity reflective cracking above concrete joint with delamination of HACP.

Page 18 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Photograph 3– McFarland Gap Road, showing typical high severity longitudinal edge cracking and block cracking. Core C11 is marked on pavement.

Photograph 4– Core C11 on McFarland Gap Road, note debonded and deteriorated asphalt above concrete slab.

Page 19 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Photograph 5–McFarland Gap Road Core C8 at MP 0.4. Core was taken at joint of two adjacent slabs, note showing material between slabs.

Photograph 6– McFarland Gap Road Core C8 at MP 0.4. Close up of concrete section of core sample, note showing material between slabs.

Page 20 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Photograph 7– McFarland Gap Road Core C4 at MP 0.05. Note the voids at interlay between lifts 2 and 3.

Photograph 8– McFarland Gap Road Core C5 at MP 0.06. Concrete was sawed, beginning of Concrete pavement.

Page 21 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Photograph 9– McFarland Gap Road Core C7 at MP 0.3 on a joint with previous repair, see tar paper at top. Wearing course lift not present. C7 was 6 feet west of C6 with wearing course.

Photograph 10 – McFarland Gap Road Core C9 at MP 0.5 at Park City intersection. C9 was the EB thru lane, no PCC present in this lane.

Page 22 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Photograph 10 – McFarland Gap Road Core C10 at MP 0.8 WB. Voids and cracks extend to 3-inch depth. Core location was at pavement crack mid-slab. Concrete core was solid.

Photograph 11 – McFarland Gap Road Core C12 at MP 0.5, Park City intersection, WB thru lane.

Concrete core was solid.

Page 23 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Photograph 12 – McFarland Gap Road, WB thru lane at Park City intersection. Corehole is C12.

Borehole B2 will at the PCC joint between the two sets of feet.

Photograph 13 – McFarland Gap Road Core B2 at MP 0.5. Note the amount and large size of incompressibles between the concrete core / concrete slab ends. AC was incompetent.

Page 24 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Appendix B – Photos of Reeds Bridge Road

Photograph 14–Reeds Bridge Road, showing typical longitudinal and transverse reflective cracking.

Photograph 15 – Reeds Bridge Road, showing typical longitudinal and transverse reflective cracking above concrete joints.

Page 25 of 25 Pages

(Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADM NISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence.MINUTE-MEMO

M:\PROJECTS\chch\10(2)_14(1)\Techserv\Pavement\Correspondence\NP-CHCH 10(2), 14(1) Preliminary Pavement Memo.doc

TO MESSAGE/COMMENT FROM/DATE

Photograph 16 –Reeds Bridge Road, showing shoulder drop off with exposed concrete slab and rub marks from vehicle tires.

Photograph 10– Reeds Bridge Road, WB core C18. Typical core sample showing bonded HACP above concrete slab.

cc: Pavement (S. Deppmeier), Highway Design (S. Siou), TS Reading w/ attachments