City of Roseville Double Chip Seal Project

Transcription

1 Draft City of Roseville Double Chip Seal Project Using AR Warm Mix and a Terminal Blend Chip Seal Report Number: CP2C February 15, 2011 CaliforniaPavementPreservationCenter 35 Main Street, Suite 205 CaliforniaStateUniversity Chico, California (530)

2 PROJECT SUMMARY PAGE Tech Report: Title: City of Roseville Double Chip Seal Project using a AR Warm Mix plus a Terminal Blend Chip Seal Authors: Lerose Lane, Paul Gowan, Ding Cheng, and Nina Buelna Prepared For: California Department of Resources Recovering and Recycling Client Reference No.: Prepared by: CP2 Center Date: February 15, 2011 Abstract: This report describes the construction of a double chip seal on various city streets within the City of Roseville, California near Sacramento. The first layer is a warm mix asphalt rubber seal coat with 3/8 inch precoated hot applied chips. The second layer is a rubber modified binder seal coat using PG76-22TR and 1/8 inch precoated hot applied chips. The warm mix additive was a wax type product provide by Engineered Additives Inc. This allowed the binder for the seal coat to be applied at a lower temperature and allowed more time for rolling the screenings/chips. The project was placed during daylight hours and proved to provide a good chip seal product. The project went down without any significant problems. The City is pleased with the project. Keywords: Asphalt rubber seal coat, warm mix additives, WMA, terminal bends ii

3 Acknowledgements We appreciate the financial support of the CalRecycle for providing the funding for this important and meaningful study. We would like to extend our gratitude to Nate Gauff and Bob Fujii of CalRecycle, who provided continuous support to this project. We would also appreciate the support from City of Roseville, Nina Buelna, Resident Engineer of City of Roseville, and especially Mr. Marc Bertsch, CA Chip Area Manager for Intermountain Slurry Seal, Inc. provided invaluable information for this report. Disclaimer The contents of this report reflect the views of the authors who are responsible for the facts and accuracy of the data presented herein. The content does not necessarily reflect the official views or policies of the California Department of Resources Recovering and Recycling, and the State of California. iii

4 Table of Contents List of Figures... v List of Tables... vi 1.0 Introduction Background Project Objective Project Scope Pre-Construction Data Existing Pavement Condition Survey Existing Pavement Structure Materials and Mix Design Construction Process Construction Paving Plan Weather during Construction Construction Observations QC data from contractor QA data from agency Emissions and Energy Consumption Problems Encountered Post Construction Appearance of Finished Mat Condition in February Future plans iv

5 5.0 Preliminary Conclusions and Recommendations References List of Figures FIGURE 1 VICINITY MAP OF THE CITY OF ROSEVILLE IN PLACER COUNTY... 2 FIGURE 2 EXISTING PAVEMENT CONDITION PRIOR TO SEAL COAT... 3 FIGURE 3 SKIN PATCH OVER DISTRESSED PAVEMENT WITH REFLECTIVE CRACKING... 4 FIGURE 4 DRAINAGE INLET COVERED WITH BUILDING PAPER FOR PROTECTION FROM CHIPS... 4 FIGURE 5 COLOR CODED WARM MIX ASPHALT RUBBER SEAL COAT SCHEDULE... 7 FIGURE 6 COLOR CODED WARM MIX ASPHALT RUBBER SEAL COAT SCHEDULE... 8 FIGURE 7 MUIR COURT WITH 3/8 INCH CHIPS BEING ROLLED WITH RUBBER TIRED ROLLER... 8 FIGURE 9 BEAR CAT CHIP SPREADER APPLYING 3/8 INCH CHIPS ON PASS ON CENTER OF STREET FIGURE 10 TRAIN OF 3 RUBBER TIRED ROLLER COMPACTING 3/8 INCH HOT APPLIED CHIPS FIGURE 11 ROLLING AND SWEEPING OPERATION OCCURRING SIMULTANEOUSLY FIGURE 12 SECOND LAYER OF SEAL COAT 1/8 INCH HOT PRE-COATED CHIPS BEING APPLIED FIGURE 13 FIRST PASS OF 2 ND LAYER OF SEAL COAT 1/8 INCH CHIPS AFTER ROLLING FIGURE 14 PG76-22TR BEING APPLIED TO 2 ND HALF OF ROAD FOR 1/8 INCH CHIPS FIGURE 15 ROLLING AFTER 1/8 INCH CHIP APPLICATION TO ENTIRE WIDTH OF ROAD FIGURE 16 THERMAL PICTURE OF ASPHALT RUBBER BINDER TEMPERATURE BEHIND DISTRIBUTER TRUCK FIGURE 17 3/8 INCH CHIPS DIRECTLY AFTER APPLICATION FIGURE 18 THERMAL PICTURE SHOWING PG76-22TR APPLICATION AT DISTRIBUTION FIGURE 19 EMISSIONS FROM ASPHALT RUBBER BINDER APPLIED AT 340 O F FIGURE 20 EMISSIONS FROM PG76-22TR ASPHALT BINDER APPLIED AT O F FIGURE 21 CHIPS ON SIDEWALK AREA FIGURE 22 MAT WITH 3/8 INCH PRE-COATED CHIPS FIGURE 23 MAT WITH 1/8 INCH PRE-COATED CHIPS FIGURE 24 INTERSECTION OF BALBOA AND LARKIN LOOKING NORTH ON BALBOA FIGURE 25 LARKIN LOOKING WEST FIGURE 26 AR DOUBLE CHIP SEAL AFTER 4 MONTHS OF SERVICE AT BALBOA AND LARKIN FIGURE 27 BALBOA NEAR MCLAUREN LOOKING NORTH FIGURE 28 SURFACE AFTER 4 MONTH OF SERVICE NEAR MCLAUREN & BALBOA INTERSECTION FIGURE 29 LIVINGSTON CT. AFTER 4 MONTHS OF SERVICE FIGURE 30 SURFACE AFTER 4 MONTHS OF SERVICE AT VAN NESS ST. AND LIVINGSTON CT FIGURE 31 JOINT CONDITION BETWEEN AR CHIP SEAL AND NON-SEAL COATED PAVEMENT AT VAN NESS ST v

6 List of Tables TABLE 1 ASPHALT CLASSIFICATION SUMMARY FOR RUBBER BINDER BY MACTEC ENGINEERING... 5 TABLE 2 CRUMB RUBBER CERTIFICATE OF COMPLIANCE DATA FROM CRM..6 TABLE 3 GRADATION FROM CERTIFICATE OF COMPLIANCE FROM CRM.. 6 TABLE 4 CONSTRUCTION TEMPERATURE DATA....9 TABLE 5 VARIOUS TEMPERATURES OF PAVING PROCESS TABLE 6 CERTIFICATE OF COMPLIANCE FOR PG76-22TR, ASPHALT RUBBER BINDER TABLE 7 GRADATION 1/8 INCH AGGREGATE BY RMA GROUP FOR CITY OF ROSEVILLE TABLE 8 GRADATION 3/8 INCH AGGREGATE BY RMA GROUP FOR CITY OF ROSEVILLE..23 TABLE 9 DURABILITY INDEX AND CLEANNNESS VALUES FOR 1/8 INCH AND 3/8 INCH AGGREGATE BY RMA GROUP FOR CITY OF ROSEVILLE. 25 vi

7 1.0 Introduction 1.1 Background This asphalt rubber seal coat project consists of a preventative maintenance treatment for various city streets within the City of Roseville. The area that is being seal coated lies within an existing upper scale subdivision that is about 25-years old. The existing pavement had not received any major maintenance until the City of Roseville initiated repairs prior to this project. The City performed dig outs where there was rutting and extreme alligator cracking, and skin patches for the other distressed areas. 1.2 Project Objective The primary objective of the project is to preserve city streets at a lower cost than repaving. The double asphalt rubber chip seal for this contract cost the City of Roseville $5.50/yd 2. The warm mix additive lowered the cost of this application $1.25/ yd 2 compared to last years bid prices for a similar project. The cost to overlay the streets with 1 inch of HMA is going to cost more due to more working days requiring traffic control, and grinding conform areas along the concrete curbs. The secondary objective of this project is to allow the California Pavement Preservation Center to study the effect that the warm mix additive has on the product and to monitor this project throughout its life. 1.3 Project Scope The project is a double chip seal with a warm mix rubber binder for the first layer with 3/8 inch precoated hot applied chips. The binder was applied at a rate of 0.60 gal/yd 2 and the chips were applied at a rate of 30 lbs/yd 2. The second layer was a PG76-22TR binder with 1/8 inch pre-coated hot applied chips. The binder was applied at a rate of 0.25 gal/yd 2 and the chips were applied at a rate of 9-10 lbs/yd 2. The warm mix rubber binder was applied at a temperature of 335 to 340 o F, which is a 60 o F reduction from the normal application temperature. The temperature reduction allows for less energy to be used in the heating process, and also reduces the emissions. The PG76-22TR binder was applied at a temperature of 350 to 360 o F, which was higher than the normal application temperature for this product. 1

8 Figure 1 Vicinity Map of the City of Roseville in Placer County 2

9 2.0 Pre-Construction Data 2.1 Existing Pavement Condition Survey The CP2 Center did the preconstruction project survey of the city street prior to the seal coat application. The City of Roseville performed dig outs and HMA skin patches prior to the double chip seal. There were areas that still had alligator cracking, and most of the existing surfacing had minor to moderate cracking. Figure 2 Existing Pavement Condition Prior to Seal Coat 3

10 Figure 3 Skin Patch over Distressed Pavement with Reflective Cracking Figure 4 Drainage Inlet Covered with Building Paper for Protection from Chips 4

11 2.2 Existing Pavement Structure One of the City s Maintenance Foreman said that the existing pavement was 3 inches thick over 4 inches of aggregate base. He said that he had performed the repair work, which included dig outs and asphalt concrete skin patches, prior in preparation for the warm mix asphalt rubber seal coat. This structural section was probably the City s standard when the subdivision was developed. The plans for this project did not show the existing pavement structural section. 2.3 Materials and Mix Design The seal coat consisted of a warm mix asphalt rubber binder followed with an application of hot precoated chips. The 3/8 inch hot pre-coated chips were supplied by Teichert s Perkins Plant near Sacramento, California. The warm mix asphalt rubber binder consisted of PG with the traditional 18% crumb rubber blend. The additives included Engineered Additives WMA at 1-1/2%. The binder had an end viscosity of 2800 centipoise at 347 o F, and it was applied at a rate of 0.6 gal/yd 2. The asphalt rubber binder was blended at Granite s Vernalis Plant, and then the asphalt rubber binder was shipped to Granite s French Camp Plant where the warm mix additive (Engineered Additives WRM) was blended. The chip rock consisted of a 3/8 inch pre-coated hot applied screenings and it was pre-coated with ½% of PG64-16 and applied at a rate of 30 lbs/yd 2. The 3/8 inch chips were from Teichert s Perkins Plant in Sacramento. The asphalt classification summary for the asphalt rubber binder is given in Table 1. The second application of binder was PG76-22TR applied at the standard temperatures of 350 to 360 o F. This was followed by an application of 1/8 inch hot pre-coated basalt chips at a rate of 9 to 10 lb/yd 2. The 1/8 inch chips were pre-coated with 0.8% PG64-16 binder and applied at a temperature of 290 o F. This material was supplied by Vulcan s Oroville Plant and shipped to Teichert s Perkins Plant for heating, and pre-coating with PG64-16 binder prior to being shipped to the Roseville project. Table 1 Asphalt Classification Summary for Rubber Binder by MACTEC Engineering Tests on Original Asphalt Rubber, min Viscosity, 347 o F, centipoise Cone Penetration, 77 o F, 150 g. Ring and Ball Softening Point, o F Resilience, 77 o F, % ASTM D2669 ASTM D217 ASTM D36 ASTM D o F min Binder Components: Sample ID: PMAR (with warm mix additives) 80% Paramount Elk Grove, CA PG 64-16, 18% Scrap Tire- Crumb Rubber Manufacturers(CRM), 2.0% Kraton D1101 SBS Polymer ( ), Added 1.5% Engineered Additives WMA to PMARB by weight of binder. 5

12 Table 2 Crumb Rubber Certificate of Compliance Data from CRM Scrap tire CRM gradation (%passing No. 8 sieve) 100% Wire in CRM (% Max) 0% Fabric in CRM (% Max) 0.05% CRM Particle Lengths (Inch max): 1/16 CRM specific gravity Table 3 Gradation from Certificate of Compliance from CRM Screen % Passing Specification (#8) 2.36 mm (#10) 2.00 mm (#16) 1.18 mm (#30) 600 um (#50) 300 um (#100) 150 um 1 -- (#200) 75 um

13 3.1 Construction Paving Plan 3.0 Construction Process The warm mix rubber binder seal coat started on Balboa Way with the 3/8 inch hot pre-coated chips and then the side streets were also seal coated. The 3/8 inch seal coat was thoroughly roller with 3-rubber tired rollers, and a steel wheel finish roller. After the rolling was completed, the seal coat was swept repeatedly until there was minimal lose of chips. Around 3:00 P. M. on September 30 th, the 1/8 inch hot pre-coated chips with the PG76-22TR terminal blend were applied in the same order as the earlier warm mix asphalt rubber layer. The fresh applied 1/8 inch hot chips were rolled immediately with 3-rubber tired rollers, and the chips were rolled again by a steel wheel finish roller, and then thoroughly swept. There were 3 self-contained street sweepers sweeping up the loose chips. Dates of construction shown in Figures 6 and 7 were September 30 and October 1, 2010, and October 5-10, Day 1 as shown on the color coded schedule below was September 30 th,, Day 2 was October 1, Day 3 was October 2, Day 4 was October 3, and Day 5 was October 4 th. The last day of construction was actually, October 12, Figure 5 Color Coded Warm Mix Asphalt Rubber Seal Coat Schedule 7

14 Figure 6 Color Coded Warm Mix Asphalt Rubber Seal Coat Schedule Figure 7 Muir Court with 3/8 inch Chips Being Rolled with Rubber Tired Roller 8

15 3.2 Weather during Construction The weather for September 30, 2010 was warm and clear. The seal coat operation started at 9:00 A. M. and the temperature was 74 o F. The day s high was 96 o F at 4:00 P. M. with light winds throughout the day. The pavement temperature was 94 o F by 10:00 P. M. The weather for October 1, 2010 had similar temperatures. The temperatures for the construction period are shown in Table 4. Table 4 Construction Temperature Data Date Project Start Time Project Start Temp ( F) Max Day Temp Min Day Temp ( F) ( F) 9/30/2010 9: /1/2010 7: /4/2010 7: /5/2010 7: /6/2010 7: /7/2010 7: /8/2010 7: /11/2010 7: /12/2010 7: Construction Observations The equipment used on the job consisted of the following: o o o o o o o o o o o o 2-Rubber Tired Roller, Volvo PT 125 R 1-Rubber Tired Roller, Cat PS 150B 1-Steel Wheeled Finish Roller, Bomag BW 117D3 1-Superior Sweeper, DT80J 1- Bear Cat Spreader CRC 2-Bear Cat Asphalt Rubber Distributer Trucks Various Trucks with end dumps for 3/8 inch pre-coated hot applied chips and 1/8 inch precoated hot applied chips 1-Water Truck (Hertz) 1-Dump Truck-Peterbilt 1-Modified Asphalt Transports with internal agitation 2-Self-Contained Street Sweepers 1-Vacuum Street Sweeper (self-contained) There were three rubber tired rollers used immediately after the application of the hot applied chips. There were a total of three street sweepers on the project. The photos in Figures 8-18 show various operations throughout the application of the double seal coat. Figure 8 shows a Bear Cat distributor truck moving to position for another pass of warm mix rubber asphalt binder application. Figure 9 shows the Bear Cat spread applying 3/8 inch pre-coated hot chips. 9

16 Figures 10 and 11 show the roller train working (three rubber tired rollers). Figure 12 shows the 1/8 inch pre-coated hot chips being applied to the PG76-22TR for the second layer of the seal coat. Figure 13 shows one-half the street with the second layer of chips. The 1/8 inch chips that comprised the second lay of the seal coat are basalt material which is naturally black in color and the material appears darker than the 3/8 inch material. Figure 14 shows the Bear Cat distributor truck applying PG76-22TR to the second half of the road, and Figure 15 shows the street after the 1/8 inch chips application. Figure 8 Bear Cat Distributor Truck Positioning for Pass for Center of Street Figure 9 Bear Cat Chip Spreader Applying 3/8 inch Chips on Pass on Center of Street 10

17 Figure 10 Train of 3 Rubber Tired Roller Compacting 3/8 inch Hot Applied Chips Figure 11 Rolling and Sweeping Operation Occurring Simultaneously 11

18 Figure 12 Second Layer of Seal Coat 1/8 inch Hot Pre-Coated Chips Being Applied Figure 13 First Pass of 2 nd Layer of Seal Coat 1/8 inch Chips After Rolling 12

19 Figure 14 PG76-22TR Being Applied to 2 nd Half of Road for 1/8 inch Chips Figure 15 Rolling after 1/8 inch Chip Application to Entire Width of Road 13

20 Table 5 Various Temperatures of Paving Process Temp ( F) Description 283 Asphalt Rubber Binder as Applied 274 3/8 inch Chip Temp as Applied 3/8 inch Chip Rolling Temp 308 PG76-22TR Temp as Applied 175 1/8 inch Chip Temp after Spreading 1/8 inch Chip Rolling Temp Figures 16 is a thermal picture showing the temperature on the pavement surface of asphalt rubber binder directly after application. Figure 17 is a thermal picture showing the temperature of the 3/8 inch chips directly after application. Figure 18 is a thermal picture showing the back of the distributor truck applying PG76-22TR. These figures show the temperature variation that occurs during the construction phase of a seal coat project, and reinforces the need for a warm mix product that can alleviate the problems encountered with areas of cooler temperatures. Figure 16 Thermal Picture of Asphalt Rubber Binder Temperature behind Distributer Truck 14

21 Figure 17 3/8 inch Chips Directly after Application Figure 18 Thermal Picture Showing PG76-22TR Application at Distribution The haul distance for the 1/8 inch chips from Vulcan s Oroville plant to Teichert s Perkins Plant was approximately 78 miles. The haul distance for the hot pre-coated 1/8 inch basalt chips and the hot precoated 3/8 inch chips from Teichert s Perkins pit to the Roseville project was approximately 26 miles. 15

22 3.4 QC data from contractor A certificate of compliance showing typical asphalt product qualities was provided by Paramount Petroleum for the terminal binder that was being supplied to a portion of the project. A copy of a portion of a typical certificate of compliance is shown below for the PG76-22TR binder. The PG76-22TR asphalt binder supplied by Paramount Petroleum is in the Caltrans certification program and is subject to intermittent testing. This binder was used on the project that was not the warm mix formula. Kent s Oil PG76-22TR was also used on this project, and was not the warm mix formula. Table 6 Certificate of Compliance for PG76-22TR, Asphalt Rubber Binder Meets Specifications: Caltrans Certificate of Compliance Tests ASTM No. AASHTO NO. Specification Result Tests on Original Asphalt: Dynamic Shear, 76 oc, G*/Sin, Kpa D7175 T min 1.44 Dynamic Shear, 76 o C, Phase Angle, D7175 T min 61.4 Viscosity, 135 o C, 21 Spindle, 20 RPM, Pa. S D4402 T max 1.54 Flash Point, C.O.C., o C D92 T min 291 Density, 15 o C, Kg/m 3 D70 T Solubility in Trichloroethylene, wt.% D2042 T min 99.7 Tire Rubber Content, wt.% 15 min 18.3 SBS Polymer Content, wt.% 3 min >3 Tests on R.T.F.O. Residue D2872 T240 Dynamic Shear, 76 oc, G*/Sin,Kpa D7175 T min 2.23 Dynamic Shear, 76oC, Phase Angle, D7175 T max 60.5 Mass Loss, % D2872 T max Elastic Recovery, 25 o C, % D6084B T301 65min 85 Tests on P.A.V. Residue@110 o C D6521 R28 Dynamic Shear, 31 o C, G*. Sin, kpa D7175 T max 1780 Creep Stiffness, -12 o C, S, MPa D6648 T max 156 m-value, -12 o C D6648 T min 0.32 Paramount Petroleum Corporation hereby certifies that the asphalt product accompanying this certificate was produced in accordance with an accepted certification program for suppliers of asphalt, and the above test data is representative of the shipment. 16

23 3.5 QA data from agency The data for the City of Roseville QA tests was performed by RMA Group, the City s consultant laboratory. Their data on the gradation of screenings is shown in Table 5 for the 1/8 inch chips, and in Table 6 for the 3/8 inch chips. The RMA Group also performed durability testing using CTM 229 for both the 1/8 inch chips and the 3/8 inch chips. The RMA Group laboratory also reported the cleanness values using CTM 227 for both the 1/8 inch chips and the 3/8 inch chips. The durability indexes and the cleanness values are shown in Table 7 for both gradations of chips. Table 7 Gradation 1/8 inch Aggregate by RMA Group for City of Roseville Date Material Test Method 9/30/2010 1/8 inch Aggregate Calif. Test Method 202 Sieve Size Result Specification (#4) 4.75mm (#8) 2.36mm (#16) 1.18um (#30) 600um (#50) 300um 0 -- (#100) 150um 0 -- (#200) 75um Date Material Test Method 10/1/2010 1/8 inch Aggregate Calif. Test Method 202 Sieve Size Result Specification (#4) 4.75mm (#8) 2.36mm (#16) 1.18um (#30) 600um (#50) 300um 2 -- (#100) 150um 2 -- (#200) 75um

24 Table 7 Gradation 1/8 inch Aggregate by RMA Group for City of Roseville (continue) Date Material Test Method 10/4/2010 1/8 inch Aggregate Calif. Test Method 202 Sieve Size Result Specification (#4) 4.75mm (#8) 2.36mm (#16) 1.18um (#30) 600um (#50) 300um 2 -- (#100) 150um 2 -- (#200) 75um Date Material Test Method 10/5/2010 1/8 inch Aggregate Calif. Test Method 202 Sieve Size Result Specification (#4) 4.75mm (#8) 2.36mm (#16) 1.18um (#30) 600um (#50) 300um 3 -- (#100) 150um 3 -- (#200) 75um Date Material Test Method 10/5/2010 1/8 inch Aggregate Calif. Test Method 202 Sieve Size Result Specification (#4) 4.75mm (#8) 2.36mm (#16) 1.18um (#30) 600um (#50) 300um 4 -- (#100) 150um 4 -- (#200) 75um

25 Table 8 Gradation 3/8 inch Aggregate by RMA Group for City of Roseville Date Material Test Method 9/30/2010 3/8 inch Calif. Test Method 202 Aggregate Sieve Size Result Specification (1/2 inch) 12.5mm 100 (3/8 inch) 9.5mm (#4) 4.75mm (#8) 2.36mm (#16) 1.18um 5 -- (#30) 600um 4 -- (#50) 300um 2 -- (#100) 150um 2 -- (#200) 75um Date Material Test Method 10/1/2010 3/8 inch Calif. Test Method 202 Aggregate Sieve Size Result Specification (1/2 inch) 12.5mm 100 (3/8 inch) 9.5mm (#4) 4.75mm (#8) 2.36mm (#16) 1.18um 4 -- (#30) 600um 3 -- (#50) 300um 2 -- (#100) 150um 2 -- (#200) 75um Date Material Test Method 10/4/2010 3/8 inch Calif. Test Method 202 Aggregate Sieve Size Result Specification (1/2 inch) 12.5mm 100 (3/8 inch) 9.5mm (#4) 4.75mm (#8) 2.36mm (#16) 1.18um 3 -- (#30) 600um 2 -- (#50) 300um 1 -- (#100) 150um 1 -- (#200) 75um

26 Table 8 Gradation 3/8 inch Aggregate by RMA Group for City of Roseville (continue) Date Material Test Method 10/5/2010 3/8 inch Calif. Test Method 202 Aggregate Sieve Size Result Specification (1/2 inch) 12.5mm 100 (3/8 inch) 9.5mm (#4) 4.75mm (#8) 2.36mm (#16) 1.18um 5 -- (#30) 600um 3 -- (#50) 300um 2 -- (#100) 150um 2 -- (#200) 75um Date Material Test Method 10/6/2010 3/8 inch Calif. Test Method 202 Aggregate Sieve Size Result Specification (1/2 inch) 12.5mm 100 (3/8 inch) 9.5mm (#4) 4.75mm (#8) 2.36mm (#16) 1.18um 3 -- (#30) 600um 2 -- (#50) 300um 2 -- (#100) 150um 2 -- (#200) 75um Table 9 Durability Index and Cleannness Values for 1/8 inch and 3/8 inch Aggregate by RMA Group for City of Roseville 1/8 inch Aggregate 3/8 inch Aggregate Durability Index Cleanness Value Durability Index Cleanness Value Date CTM 229 CTM 227 CTM 229 CTM 227 9/30/ /1/ /4/ /5/ /6/ Specification 80 Min. 88 Min. 70 Min. 80 Min. 20

27 Note: Not all of the aggregate materials met the specifications for gradation, and cleanness value. The City s contract had a pay reduction clause, and a removal clause if the materials were outside of the specified allowable tolerances by more than +/-4%. 3.6 Emissions and Energy Consumption The rubber asphalt binder and the PG76-22TR binders both had some emissions. Due to the asphalt rubber binder being spread at a 60 o F cooler temperature, there were significantly fewer emissions with its application than when applied at 400 o F. The emissions shown in in Figure 19 for the asphalt rubber binder being applied at o F, and the emissions in Figure 20 appear similar for the PG76-22TR being applied at o F. There is a substantial reduction in emissions for the asphalt rubber binder from the emissions at the normal application temperature of 400 o F. The 60 o F lower application temperature for the asphalt rubber binder also uses less energy to heat the product. The PG76-22TR should be applied at a lower temperature of about 330 o F to reduce emissions. Figure 19 Emissions from Asphalt Rubber Binder Applied at 340 o F 21

28 Figure 20 Emissions from PG76-22TR Asphalt Binder Applied at o F 3.7 Problems Encountered One problem that was observed, as shown in Figure 21, was that some the 3/8 inch chips bounced onto driveways and sidewalks. The sweeping operation caused the displacement of the chips from the road to the sidewalks and driveways. Several residents expected the Contractor to sweep the chips off of their sidewalks and driveways as part of the project. There were also minor instances of some overlap of the rubber asphalt binder at a few locations that took away from the overall smooth appearance. A common occurrence of applying asphalt rubber binder, that was previously reported, is that the binder occasionally plugs the spray nozzles on the spreader bar. Figure 21 Chips on Sidewalk Area 22

29 4.1 Appearance of Finished Mat 4.0 Post Construction The surface of the job was uniform and the screenings appeared to be adhering well. Photos of the completed job are shown in Figures 22 and 23. Figure 22 shows the 3/8 inch hot applied chips after rolling and prior to second layer of 1/8 inch chips being applied. Figure 23 shows the 1/8 inch hot applied chips after rolling. Figure 22 Mat with 3/8 inch Pre-Coated Chips Figure 23 Mat with 1/8 inch Pre-Coated Chips 23

30 4.2 Condition in February 2011 A visit to the project site took place on February 7, The following photos show the condition after about 4 months in service. Overall the condition of the asphalt rubber double chip seal product looks good as does the rest of the project. Figures 24 through 31 are pictures that show the project s conditions at various locations. Figure 24 Intersection of Balboa and Larkin Looking North at Balboa 24

31 Figure 25 Larkin Looking West Figure 26 AR Double Chip Seal After 4 Months of Service at Balboa and Larkin 25

32 Figure 27 Balboa Near McLauren Looking North Figure 28 Surface After 4 Month of Service Near McLauren & Balboa Intersection 26

33 Figure 29 Livingston Ct. After 4 Months of Service Figure 30 Surface After 4 Months of Service at Van Ness St. and Livingston Ct. 27

34 Figure 31 Joint Between AR Chip Seal and Non-Seal Coated Pavement At Van Ness St. 4.3 Future plans It is proposed to monitor the performance of the trial area of warm mix asphalt rubber seal coat over the life of the project, starting on a yearly basis. Criteria will include rock loss, reflective cracking, and flushing. 28

35 5.0 Preliminary Conclusions and Recommendations This warm mix section appears to have the advantages of fewer emissions and provides a longer time period for the placement and rolling of the pre-coated hot applied 3/8 inch screenings. There was a 60 o F drop in the asphalt rubber binder application temperature. Due to the width of the city streets, three rollers were used by the contractor. This technology also uses less energy and has reduced emissions. Also, this maintenance strategy may reduce the alligator cracks from reflecting through, and it should last for a period of 10 years. The double chip seal also has the advantage of a smoother mat with less tire noise by using 1/8 inch pre-coated hot applied chips for the second coat. 29

36 6.0 References 1. Intermountain Slurry Seal, Inc., various personnel, October, City of Roseville, Resident Engineer, Nina Buelna P. E., October, Various City of Roseville staff, September 30, Granite Construction/Intermountain Slurry Seal, Inc., Superintendent, Marc Bertsch, October, Binder Design, MACTAC Engineering, Phoenix Arizona, Provided by Marc Bertsch, October,