Click for next page ( 27


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 26
26 CHAPTER THREE PERFORMANCE OF OVERLAYS FROM SURVEYS AND INTERVIEWS This chapter reviews performance in the field based on infor- mental bridges but does not have deck problems; Iowa mation from agencies, contractors, and material suppliers. had installed one and indicated that it performed poorly; and Montana had installed 30 to 35, but stated that administrative problems made it too time consuming SCOPE OF SURVEYS to enforce the specifications. Alberta has constructed 139 TPOs, with the last one placed in 1999, but plans Surveys were sent to all states and Canadian provinces. to use no more in the future. Alberta experienced some The questionnaires are in Appendix A. Each agency was problems with TPOs placed initially, but when those asked to complete a general survey form ("Agency Ques- problems were resolved, the overlays performed well. tionnaire") and to complete a form for each TPO or group Eventual problems with achieving adequate inspection of TPOs ("Information on Each TPO"). If agency forces and wet, rainy conditions in some parts of the province were used to install the overlay, they were asked to com- were reasons cited for discontinuing their use. British plete an "Agency-as-Installer Questionnaire." Few states Columbia installed two but reported high cost and poor completed the form for the individual TPOs. Follow-up performance as reasons for no longer using them. telephone interviews were conducted with representatives Most of the states indicated more than one reason for from the agencies that had constructed the greatest num- the use of TPOs; improving skid resistance was the ber of TPOs. Materials suppliers and contractors identi- most often cited reason, with extending the life of fied by the agencies were then interviewed by telephone to the deck the next most cited. Other reasons included obtain information. repairing spalled and cracked surfaces, restoring a uni- form appearance, and waterproofing the deck. Nearly all states use epoxy resins. Many did not GENERAL RESPONSES respond as to the construction type, but the majority of states that did indicated that multiple layer was the Responses were received from 40 states and seven prov- preferred method. California was an exception, having inces. Seven states and three provinces reporting have never installed over 500 premixed polyester overlays. Other used TPOs. Table 1 summarizes the findings. The informa- West Coast states also use premixed systems. tion includes The majority of states use contractors for installation, but 10 states use their own forces for at least some Number of overlays placed. Approximately 2,400 installations. TPOs have been installed by the states and 147 by New Mexico, Georgia, and LaGuardia Airport require the provinces reporting, a fourfold increase over the warranties ranging from 1 to 10 years. 555 reported to have been installed through 1999 Many states have specifications available. (4). California has placed the most (520), but each of seven other states, Missouri, Virginia, New Mexico, Michigan, Ohio, Kansas, and Utah, and one province, OVERLAY COST Alberta, has placed 100 or more. Ohio and North Carolina reported the first use of TPOs Three states reported overlay costs. Virginia reported a in the 1970s. Four states (California, Missouri, Oregon, cost of $60/m 2 ($50/yd 2) for an epoxy multiple-layer TPO and Virginia) and Alberta began applying overlays in installed by a contractor in 2005, and Alaska reported a cost the 1980s. of $114/m 2 ($95/yd 2) for an epoxy-urethane TPO installed Three states (Florida, Iowa, and Montana) and two by a contractor in 2007. Kansas DOT reported that between provinces (Alberta and British Columbia) no longer use 2001 and 2008 the cost of shot blasting and placement of TPOs. Florida indicated that it had installed 30 on seg- TPOs averaged $66/m 2 ($55/yd 2).

OCR for page 26
TABLE 1 SUMMARY OF STATES AND PROVINCES SURVEY State No. Placed First/Last Year Future TPOs Reasons for Use TPO System Installer Warranty, Failures Specs Avail. Comments Year AK 2 2007 Yes l, a, w P PM Agency N/A No No Excessive wear in tire lanes AL 31 1992/1994 Yes sf, l, a, s, w Any Agency N/A No No AR 0 N/A N/A N/A N/A N/A N/A N/A N/A AZ No state DOT TPOs CA 520 1983/2008 Yes sf, l, s, w P PM Contract N/A Yes Sent P PM, E ML Snow chain rutting problems CO Used, but no information available CT Not used DE 1 2007 Yes l E ML N/A N/A No No Too expensive FL 30 2000/2003 No w HMWM sealer N/A N/A No No Protect cables in segmental bridges GA 10 Mid-1990s/2007 Yes sf, l, a EU ML Contract 10 N/A Sent E ML HA 0 N/A No N/A N/A N/A N/A N/A N/A IA 1 1986 No Trial N/A N/A N/A N/A No Poor performance ID 2 2003/2007 Yes sf, l, w E ML, EU ML N/A N/A N/A N/A IL 24 1996/2007 Yes l, w E ML Contract N/A Yes Sent E ML a KS 100 +13 1999/2009 Yes w, l, s E ML Contract None 1 E ML Failed due to deck contamination MD 1 2000 N/A w E ML Agency N/A Small cracks No Worked pretty well ME 1 1 bridge TPO DOT Installation MI 100s 1995/2007 Yes sf, l, a, s E ML Contract, N/A Yes Yes Poor bond from poor surface agency prep MS No information available MN 5 2006/2007 Yes sf, l, w E ML Agency N/A No N/A MO >300 1989/2007 Yes sf, l, a, w E ML, EU ML, Contract N/A Yes Sent E PM MT 35 1995/2000 No N/A N/A Contract N/A Yes No Inspection process QC/QA difficulties NC 50 1975/1990 Yes w E ML Agency N/A Yes No ND Used, but no information available NE 0 N/A No N/A N/A N/A N/A N/A N/A NH 2 EU ML Contract Yes Yes Improve skid resistance, life and look of bridge 27 Table 1 Continued on p.28

OCR for page 26
Table 1 Continued from p.27 28 State No. Placed First/Last Year Future TPOs Reasons for Use TPO System Installer Warranty, Failures Specs Avail. Comments Year NJ 0 N/A No N/A N/A N/A N/A N/A N/A NM 250 1995/2008 Yes sf, l, a, s, w E ML, EU ML Contract, 5 Yes Online Inspection process QC/QA agency difficulties NY 44 1999/2007 Yes l, w M PM, E ML, Contract N/A Only one Sent Wearing surface aggs EU ML, P ML MMA OH 147 + 15 +1b 1979/2006 Yes l, s E ML Agency, N/A Yes No Over 100 failures in late '90s polycarb OK 10 2003/2007 Yes sf, l, w E ML, EU ML N/A N/A N/A N/A OR 35 1981/2007 Yes l, s, w E ML, P PM, Contract N/A Yes N/A Mostly for traction M PM SC Les Floyd, not used SD 0 N/A No N/A N/A N/A N/A N/A N/A TN 3 2000/2005 Yes sf, l, w E ML Contract N/A N/A N/A TX 12 1998/2008 Yes sf, l, a, s, w E ML Contract N/A N/A N/A UT 100 2001/2007 Yes sf, l, w E ML Contract N/A N/A N/A Too expensive VA 300 1981/2008 Yes sf, l, a, s, w E ML, P ML, P Contract, N/A N/A Yes Bridge deck preservation PM, M PM agency WV 8 1997/2007 Yes sf, l, w E ML, U ML N/A N/A N/A N/A WY 61 1990/2005 Yes sf, s E ML Contract, N/A Yes Yes Mostly for traction agency Canadian Provinces AB 139 1984/1998 No N/A N/A N/A N/A N/A N/A Poor performance, too expensive BC 2 1990/1991 No N/A N/A N/A N/A N/A N/A Poor performance, too expensive MB 0 N/A No N/A N/A N/A N/A N/A N/A NB 5 2005/2007 Yes l, s, w E ML Agency N/A Yes N/A NS 0 N/A No N/A N/A N/A N/A N/A N/A NT 1 1991 Yes s, w E ML Contract N/A N/A Sent ON 0 N/A No N/A N/A N/A N/A N/A N/A Poor performance, too expensive NOTE. sf = restore surface friction; l = extend life of deck, including additional cover; a = restore uniform appearance of deck surface; s = restore surface to previous spalled, cracked, and repaired deck; w = waterproof deck; P = polyester-styrene; E = epoxy; EU = epoxy urethane; HMWM = high-molecular-weight methacrylate; M = methacrylate (slurry); PM = premixed; ML = multiple lift; N/A = information not available from agency. b147 by Ohio, 15 by counties, 1 by city. a100 by Kansas, 13 by counties.