TX_FLAP_100(1),_Buena_Vista_Road_Pavement_Report.pdf

TX FLAP 100(1)

Buena Vista Road

PAVEMENT Report

October 2017

Report Prepared By

U.S. Department of Transportation Federal Highway Administration

Central Federal Lands Highway Division Lakewood, Colorado http://www.google.com/imgres?sa=X&biw=1280&bih=819&tbm=isch&tbnid=gtpyJEKxSQX6SM:&imgrefurl=http://portal.hud.gov/hudportal/HUD?src=/press/press_releases_media_advisories/2010/HUDNo.10-242&docid=0hzyuk4oobnONM&imgurl=http://portal.hud.gov/hudportal/images/hudimg?id=dot_logo_41193.jpg&w=520&h=528&ei=uGw7Uoy6Ksjk4AOC_IDQBw&zoom=1&iact=hc&vpx=567&vpy=131&dur=635&hovh=226&hovw=223&tx=151&ty=150&page=1&tbnh=154&tbnw=162&start=0&ndsp=30&ved=1t:429,r:26,s:0,i:171�

TX FLAP 100(1), Buena Vista Road iii

TABLE OF CONTENTS

I. INTRODUCTION

II. CLIMATE

III. EXISTING PAVEMENT

IV. EXPLORATION

V. TESTING RESULTS

VI. RECOMMENDATIONS & DISCUSSION

APPENDICES

A – Location Map B – Laboratory Test Results C – Photographs D – Pavement Design Calculations

I. INTRODUCTION

During the week of July 24th, 2017, a pavement and subgrade soil investigation was completed at the Laguna Atascosa NWR on Buena Vista Road. The purpose of the pavement investigation was to determine current pavement and base thickness, as well as the classify the soil below, for the TX FLAP 100(1) construction project.

TX FLAP 100(1), at this time, consists of Buena Vista Road. Buena Vista Road beginning at the intersection with General Brant Road and proceeding 2.7 miles North to the intersection at Lake Side Drive. Buena Vista Road is the access road to the Laguna Atascosa NWR. The existing width of Buena Vista Road is 20 feet wide, with approximately 1.5 inches of asphalt, 8 inches of base.

Five bore holes were drilled through the existing pavement on Buena Vista Road. See Tables 1 for a summary of layer thicknesses and soil description. Materials testing reports and photos are shown in the Appendix.

II. CLIMATE

Climate

The Laguna Atascosa NWR experiences warm weather year-round. Average temperatures during the summer range from 77°F to 95°F. During the winter the temperatures ranges from 52°F to 72°F. Spring and fall the temperatures range from 67°F to 85°F. Most months are typically dry with a rainy season in September into October. Thunderstorms in the summer and fall occur on occasion.

III. EXISTING PAVEMENT

Existing Pavement

The existing pavement on Buena Vista Road is predominately asphalt pavement.

The major distress in the pavement throughout the roads is cracking, stripping and pot-holes.

The prominent distress is pot-holes, which appears to occur due to moist clay subgrade and a thin existing pavement section. Currently large potholes are filled in with aggregate base course, but the aggregate base course appears to quickly wash away. Because of this it is necessary to pulverize the existing asphalt and base layer and construct a new pavement surface.

IV. EXPLORATION

On July 27th-28th, 2017 a two-person crew from Terracon, Inc. from McAllen, TX was on-site with CFL staff to conduct the drilling. Terracon supplied one person for the traffic control. A truck-mounted drill rig was used to auger drill 5 locations. The borings were drilled to a depth of approximately 5 feet. All borings were drilled within the roadway. The holes were recorded by CFL. The pavement thickness and base thickness were consistent. Most of the samples appeared to be silty-clay soils. The soils classified as A-7-6 and A-6 material using the AASHTO Soil Classification system. See Tables 1 for a summary of the soils.

V. TEST RESULTS

Table 1 provides a summary of the drill locations and soil properties.

TABLE 1:

Buena Vista Road Location and Soil Properties

Bore Hole

Location Mile Post

(MP)

Asphalt Thickness (inches)

Aggregate Base Course

Thickness (inches)

Soil Classification

R-value (Resilient Modulus) Remarks

1 MP 0.0

East Lane 1.5 8 A-7-6 (54) <5

(3,775) Wet, brown silty clay

2 MP 0.5

west lane 1.5 8 A-7-5 (38) <5

(3,775) Wet, brown silty clay

3 MP 1.5

east lane 1.5 8 A-6 (13) 9

(5,995) Wet, brown silty clay

4 MP 2.0

west lane 1.5 8 A-6 (19) <5

(3,775) Wet, brown silty clay

5 MP 2.5

east lane 1.5 8 A-6 (9) 10

(6,550) Wet, brown silty clay

VI. PAVEMENT RECOMMENDATIONS AND DISCUSSION

The structural sections were designed using the 1993 AASHTO Pavement Design DARWin Pavement Design and Analysis System program. The traffic on this road is low and composed of cars, personal trucks, SUV’s, and some RV’s. The design period is 20 years, A reliability level of 85% was used to calculate the soil support value for each road. Each road was designed using traffic data from the refuge for the specific road. Those values can be found in the appendix.

The subgrade soil is A-7-6 and is unsuitable for borrow material. All effort should be made to stay out of this material. If any material needs to be added it needs to be imported. The design R-Value was converted to a soil resilient modulus (Mr) using the following equation:

29.11

)5( 1 +

ValueRS

= 24.6 72.181

S rM

1) Buena Vista Road: The resilient modulus, Mr, for design is 6,550 psi, corresponding to a R-value of 10. The Mr and the traffic data equates to a required structural number (SN) of 2.02 based on DARWin program.

The recommended structural section is 3” of hot mix asphalt concrete pavement (HACP) over 6” of pulverized base on top of the existing subgrade, see figure 1:

3" of HACP

6" of Pulverized Base

Existing Subgrade

Figure 1 – Flexible Pavement Design

Drainage, Subexcavation, and other Issues

During the pavement investigation, silty clay soils were observed. Although no subexcavation locations were noted, it is recommended to include a discretionary amount of subexcavation in the contract in case it is needed.

Pavement Materials Recommendations:

Use 40301-0100, Asphalt Concrete Pavement (HACP) Type 1. The design unit weight for estimating HACP is 145.0 lb/ft3. The HACP should be placed in 2 lifts.

LTPP Bind recommends the asphalt cement a PG 70-10. The approved 403 mix should use asphalt from local source.

A fog seal, bid item 40601-0000, should be included in the contract. For determining quantities use an application rate of 0.10 gal/yd2. The emulsion type can be a CSS-1, CSS-1h, SS-1, or SS-1h.

A prime coat should be applied on the base course material prior to paving. Bid Item 41102-0000. For determining quantities use an application rate of 0.30 gal/yd2.

41201-0000, Tack coat (at 0.10 gal.yd2) is required between each lift and should either be a CSS-1. CSS-1h, SS-1, or SS-1h emulsified asphalt.

An item for blotter material, Bid Item 41105-0000 should be included at 14.75 lb/yd2.

Recommended pulverizing depth will be 6-inches. Use Bid Item 30402-5300 by the Mile. Do not begin until the asphalt mix design has been approved.

Depending on estimated aggregate base quantities, use a 302 bid item if the quantity is less than 5000 tons and a 301 Bid Item if the quantity is greater than 5,000 tons.

The design unit weight for aggregate base is 138.0. lb/ft3.

APPENDICES

A – Location Map

B – Laboratory Test Results

C – Photographs

D – Pavement Design Calculations

APPENDIX A

LOCATION MAP

APPENDIX B

LABORATORY TEST RESULTS

APPENDIX C

PHOTOGRPAHS

Existing Roadway

Existing Roadway

Existing Roadway Bore Location

Existing Roadway Bore Locations

Material from bore hole #1

APPENDIX D

PAVEMENT DESIGN CALCULATIONS

AASHTO Flexible Pavement Design

Design Parameters:

Standard Normal Deviate -1.037

Combined Standard Error 0.45

Design Serviceability Loss 1.70

Desired Level of Reliability (percent) 85.00

Asphalt Concrete Layer Coefficient 0.44

Aggregate Base Layer Coefficient 0.15

Aggregate Base Drainage Coefficient 0.80

Subbase Layer Coefficient 0.08

Subbase Base Drainage Coefficient 0.60

Flexible Pavement Structural Design:

Allowable 18-kip ESAL Repetitions 36,500.00

Resilient Modulus (psi) 6,550.00

Asphalt Concrete Thickness (inches) 3.00

Aggregate Base Thickness (inches) 6.00

Subbase Thickness (inches) 0.00

Design Structural Number 2.04

Required Structural Number 2.02

Design Life (years) 20.00

Asphalt Concrete Thickness (inches) 3.00

Aggregate Base Thickness (inches) 6.00

Subbase Thickness (inches) 0.00

Distribution