Chip Seal News & Views

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1 Chip Seal News & Views by Tom Doolittle, Doolittle Construction Phone # , Issue 2, February 2007 Double Chip Seal Proves It s Worth (Second in a series of articles on this subject) Double chip seal may be the most cost effective way to deal with asphalt pavement that has deteriorated too far to be saved by a single chip seal. It will hold up better than a thin overlay because it bonds better to the old pavement, it seals better, it is more flexible than an overlay. But this needs ongoing scrutiny, as these pavements age, to substantiate this. 3 rd Street, off SR 101, in Port Angeles. June 2005 (above) The City of Bainbridge Island continues their double chip seal program, doing 55 miles in the last 8-1/2 years. It has worked very well, bridging over cracks and alligatored areas, and holding up much better than a single chip seal. The City of Bothell roadway (also detailed in our last edition) continues to do well. Auburn, Olympia, Port Angeles & Puyallup have seen the value of this, and have added this surface treatment as one of their options in pavement preservation. In June of 2005, we applied a double chip seal to 3 rd Street, a very busy block leading into a big grocery store and gas station, just off of SR 101 in Port Angeles. This was a small part of a double chip seal that we placed on 100,000 square yards throughout the city. What was unusual about this one block was that the pavement was alligatored throughout the entire block. The City said that it had been 40 years since it had seen any maintenance. The proper (and much more costly) method of repair would have complete reconstruction, removing the existing pavement, and replacing it with hot mix asphalt. However, since the subgrade was determined to be in relatively good shape, the city decided chip sealing this block was worth a try. One and a half years later, same location 1

2 Liquid asphalt CRS-2P was used in Port Angeles, with ½ -1/4 for the bottom lift, 3/8 -#10 for the top lift, then a CSS-1h fog seal was applied afterwards. Note the texture and the cracks of the old pavement (Port Angeles - June 2005) No sign of any cracks (Picture taken November 2006) 2

3 City of Auburn s double chip seal City of Auburn s Kersey Road SE received BST patching in select locations, before a double chip seal, with a fog seal. Tighter Specs at Some Agencies Lead to Side Effects for Other Municipalities Several agencies, most notably Pierce County and Mason County, tightened their rock specifications recently to create a narrower band for both their ½ chip and their 3/8 to #4 chip. (So each product is more of a one-size chip, with a higher percentage of fractured rock.) This gives the user a higher quality chip seal, but it is difficult to make, so consequently, the cost is higher. These requirements cause unpredictable changes for those agencies that haven t tightened their rock specifications. For example, on our WSDOT project in Mason County, the ½ to #4 crushed screenings, purchased from Miles Sand and Gravel, were close to the maximum allowable on the #4 screen (averaging over 11% with one sample at 14%). I believe that too much of this smaller rock reduced the quality of the chip seal. The rock was different from what I had purchased the previous year at the same Shelton plant, which averaged 4 to 5% on the same #4 screen. They were making a one-size chip for Mason County this year, and I assume that they added some of the reject from that product to our chips. Miles S&G was not at fault, they were making specification rock, but the quality of their product was less than it could have been. In Pierce County, Glacier Sand and Gravel made only the more expensive one size 3/8 chip, with a different washing process. The end result was a quality rock, but with higher prices and less availability than the year before. (Because now it was by special order only, we couldn t just haul it out continuously, as we did in previous years). WSDOT is in the process of tightening their standard specifications for crushed screenings. This is the standard that most agencies use. Hopefully, this will give more uniformity for all involved. Parts of the busy 15 th Ave. SW, east of the Super Mall, and 53 rd Street S.E. also received a double chip seal 3

4 Other Picture Highlights of the 2006 Chip Seal Season. This season was notable for the wide variety of asphalts types used; and the number of cities that used double chip seals. City of Olympia Jefferson Avenue (above) during the first of two lifts. City of Olympia uses hot rubberized asphalt (AC15-5TR) and precoated chips. 1/2 ¼ rock was used on the first lift, then 3/8 - #10 on the second. The crushed screenings were pre-coated with paving grade asphalt first in a hot mix plant. A few streets received a double, but most received a single chip seal. The advantage of this type of asphalt is that by evening, it is all swept up; there is no sign of recent construction, only the improved roadway. It sets up quickly; after sweeping it doesn t shed any more rock. The color is darker, there is no need to fog seal. 4

5 City of Mountlake Terrace Mountlake Terrace s project: 3/8 chip seal using CRS-2P with a fog seal afterwards - several arterials including 66 th (shown above), 56 th into downtown, and 58 th leading to City Hall. Chip seal after patching an alligatored area on 58 th in Mountlake Terrace 5

6 City of Puyallup The City of Puyallup has an annual chip seal program that seals their residential streets, as well as their busiest arterials. A single chip seal using 3/8 chips with a CSS-1H fog seal afterwards is used on most streets, such as 39 th Street SE (above) However, part of busy Shaw Road, which is in need of reconstruction, will be as good test, as it received a double chip seal this year, after BST patching in select locations. Fog seal after a 3/8 chip seal in Puyallup. The streets are sealed half at a time, to allow local residents access 6

7 WSDOT Projects WSDOT (Olympic Region) had an extensive program that included Sections on SR 109 at Moclips, Pacific Beach, and Ocean Shores; SR 119 at Lake Cushman; SR 106 along Hood Canal; and SR 161 north of Eatonville. The asphalt that they chose for the ocean sections was Albina Asphalt s RS-LTP rapid set-low temperature polymer asphalt), because of the unpredictable weather. Liquid asphalt CRS-2P with ½ -#4 aggregate was used on the other sections. 7

8 Chip Seal Prices Stabilize, After a Huge Increase Last Year There have been numerous articles recently on the sharp increase in the cost of highway projects. This increase is due to high demand and higher costs for all types of raw materials, but liquid asphalt took one of the bigger jumps of any major commodity in 2006, more than doubling. Availability of asphalt was a major problem as well, as changes in the refining process (leaving less asphalt per barrel of oil) caused shortages nationwide, as well as in Western Washington. Rollers working along the ocean near Moclips on SR 109 (above), and along Hood Canal, SR 106 (below) Finally, there has been some good news on this front, as asphalt will be more abundant this year (2007), and the price has already come down 20%. However, crushed rock prices continue to go up, much higher than the general rate of inflation. Dump trucking costs have gone up 15% per year for 3 years in a row. Labor and fuel continue to be a factor. But, all factors considered, chip seal prices should go down from their peak of last summer. Pick-up sweepers were used on most of our projects. Two of them are dumping their hoppers (above) 8

9 City of Bainbridge Island Wider Acceptance Fewer Complaints Applying the second of two lifts to a hill above Puget Sound The City had another 6 miles of double chip seal this past year, using liquid asphalt CRS-2P, with ½ -1/4 rock on the bottom lift, and 3/8 -#10 for the top lift. One big change in their program was to add a CSS-1h fog seal afterwards. Complaints about chip seals have dropped down considerably in the last few years because of several factors: PCMS boards (above) are very effective, not only to slow the traffic while the loose gravel is on the road, but also to give advance notice of the date. Better Public education beforehand Better traffic control & more signing, including construction speed limits. Sweeping as soon as possible, then follow it up with a second sweeping. Fog seal: Improves rock retention, striping contrast is sharper, & it takes away some of the coarseness. 9