Microsurfacing (2010) / Chapter Skim
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Pages 55-63
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From page 55... ...
Results of the Maine Case Study This 5-year field evaluation found that microsurfaced sections showed considerably more wear than the HMA overlay sections. The details are as follows: • Most high spots of the microsurfaced roadway have been abraded by winter snow removal equipment.
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From page 56... ...
Both microsurfacing sections were visibly abraded by snow removal equipment. The report states: "Most high spots of the microsurfaced roadway have been abraded by winter snow removal equipment." Given this premise, the three performance measures studied (International Roughness Index, rut depth, and friction number)
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From page 57... ...
treatment prices for larger jobs. To capitalize on that opportunity and keeping in mind that microsurfacing was demonstrated to be very effective at reducing intersection-related crashes, when TABLE 43 YORK REGION CASE STUDY FACTS Item Data Binder CSS-1h Aggregate Type III Mineral Filler Non-air entrained portland cement Job Mix Design -- Typical Aggregate 100% Portland cement 2.0% Water 10.0% Binder 11.5% + 1% Test Specification -- Typical Residual asphalt 6.0% to 11.5% Wet track abrasion -- 1 h 538.0 Wet track abrasion -- 6 day 807.0 Excess asphalt loaded wheel 538.0 Wet stripping 90.0 Compatibility 11 pts Location 28 sites through the Reg io n of York AADT 1,000 to 7,000+ Distress Level Before Microsurfacing IRI ( m/km)
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From page 58... ...
Therefore, the lesson learned in this case is as follows: Microsurfacing is a "green" alternative and can be used to promote sustainable maintenance practices by using recycled waste products such as mine chat for aggregate and products such as fly ash and cement kiln dust as mineral filler. The second lesson learned comes from the special aggregate gradations used by the Oklahoma DOT.
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From page 59... ...
The Georgia DOT evaluated friction, crack propagation, and road noise. TABLE 44 OKLAHOMA DOT CASE STUDY FACTS Item Data Binder CSS-1h Aggregate See Table 45 Mineral filler Non-air entrained portland cement Job Mix Design -- Typical Aggregate 90% Portland cement 2.0% Water 9.0% Binder 9% + 1% Test Specification -- Typical Residual asphalt 8.0% to 13.0% Wet track abrasion -- 1 h Not available Wet track abrasion -- 6 day Not available Excess asphalt loaded wheel Not available Wet stripping Not available Compatibility Not available Location I-40 in Oklahoma City: 2 sites US-64 in Tulsa: 1 site AADT AADT = average annual daily traffic.
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From page 60... ...
Lessons Learned The major lesson from this case study deals with the qualitative aspects of microsurfacing and its use as a "quick fix" to enhance the appearance of a road at a low cost while extending its life and enhancing the safety of the traveling public by TABLE 46 GEORGIA DOT CASE STUDY FACTS TABLE 47 GEORGIA DOT CASE STUDY AGGREGATE GRADATION TABLE 48 COMPARISON OF MICROSURFACING ROAD NOISE TO OTHER COMMON SURFACES Item Data Binder CSS-1HLM (Ralumac with 3% natural latex) Aggregate See Table 47 Mineral filler Type I portland cement Job Mix Design -- Typical Aggregate 100% Portland cement 1.0% Water 10.0% Binder 7.4% Test Specification -- Typical Residual asphalt 6.8% Wet track abrasion -- 1 h 807 Wet track abrasion–6 day 538 Excess asphalt loaded wheel 538 Wet stripping 90% Compatibility Pass Location I-285 in Atlanta, Georgia AADT 55,650 Distress Level Before Microsurfacing IRI (m/km)
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From page 61... ...
It was included because much of the nation's InterItem Data Binder CSS-1HLM (Ralum ac) Aggregate See Table 50 Mineral filler Type I portland cement Job Mix Design -- Typical Aggregate 100% Portland cement 1.75% + 0.25% Water As required Binder 7.6% + 0.4% Test Specification -- Typical Residual asphalt 6.8% Wet track abrasion -- 1 h Not available Wet track abrasion -- 6 day Not available Excess asphalt loaded wheel Not available Wet stripping Not available Compatibility Pass Location US-77 in Cowley County, Kansas AADT AADT = average annual daily traffic.
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From page 62... ...
The 6-month IRI was found to have decreased by 22% for lanes constructed with scratch and wear course mixtures, and by 58% for lanes constructed with rut-fill and wear course mixtures. • Rut conditions as measured after construction showed the following results: – A 4% to 6% decrease for lanes constructed with scratch and wear course mixtures, TABLE 50 KANSAS DOT CASE STUDY AGGREGATE GRADATION Sieve Size Percentage Passing KDOT 3/8 (9.5 mm)
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From page 63... ...
Item Data Binder CSS-1 using PG 49-34 asphalt binder Aggregate Type II Mineral filler Type I portland cement Job Mix Formula -- Typical Aggregate 100% Portland cement 1.75% + 0.25% Water As required Binder 12.5% and 16.5% + 0.4% Test Specification -- Typical Residual asphalt 8% to 8.5% Softeni ng po in t 12 8 o F Penetration 163 Excess asphalt loaded wheel Not available Wet stripping Not available Compatibility Pass Location Minnesota Road Test Facility Albertville, MN AADT -- Test road 80 truck passes per day Distress Level Before Microsurfacing IRI ( m/km ) 1 .24 to 3.25 (52.6 to 57.6 in./mile)
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