Chip Seals in Manitoba
Chip Seals in Manitoba
Historical •
•
Two in-house crews, high float emulsion (150hp), graded aggregate. Between 400km to 500km annually. ~ 8,200km (5,100 mi) Bit pavement & 4,300km (2,700 mi) AST ~ 2008 amortize over 7 years, changed from maintenance budget to capital, internally changed name to “High Performance Chip Seal” (marketing to finance)
MI Graded Aggregate: ASTM 5/8” 1/2” No.4 No.40 No.200
Issues • Were not doing any chip seals on our priority roads due to issues with flying stones using graded aggregate and high float emulsion. • Public complaints.
Solution! • Rapid set emulsion, clean uniform aggregate. • 2014 test site, 6 different treatments. • Consultant from Alberta
6 Treatments Were Tested: 1.
Microsurfacing
2.
Cape-Seal
3.
Chip Seal (In-House)
4.
Fiber Mat
5.
Uniform (Single Aggregate)
6.
Racked-In
7.
Untreated
Results from Test Site • Rapid set polymer modified performed better in cracking, racked-in performed slightly better than single sized aggregate.
Challenges • Some people internally thought aggregate would be very expensive. • Some reluctance to contract out chip seal. • Some question effectiveness of chip seal on busy road.
2017 Chip Seal Contract • Used Alberta specifications, used in test project. • Warranty based, one year.
ASTM
1/2” 3/8” No.4 No.16
No.200
Contract #1 • ~50km, 31 mi • 3 sections, AADT from 4000 to 1500 • Contractor MSO (experienced from Ontario)
Design • 1.8 l/m2 (0.40 gal/yd2), test section was 2.0 l/m2 (0.44 gal/yd2) • No fog seal • Granite source aggregate
More Money $$ Contract 2 • • • •
150 km ~ 90 mi Specified slightly smaller aggregate Try fog seal on some sections Inexperienced contractor
Result • We like the fog seal so far, less flying stones, better appearance. • With limestone aggregate, have to watch to make sure application rate isn’t too high, dusty.
Changes In Project Selection • Past, condition based, reactive. Segment had to have some cracking to be considered a good candidate for chip seal. >15% extent
Current • Based on age and treatment history, if no treatments in last 7 years consider chip seal if good ride and rut. • IRI threshold ~1.9 m/km (120in/mi), ideally
Historical •
•
Two in-house crews, high float emulsion (150hp), graded aggregate. Between 400km to 500km annually. ~ 8,200km (5,100 mi) Bit pavement & 4,300km (2,700 mi) AST ~ 2008 amortize over 7 years, changed from maintenance budget to capital, internally changed name to “High Performance Chip Seal” (marketing to finance)
MI Graded Aggregate: ASTM 5/8” 1/2” No.4 No.40 No.200
Issues • Were not doing any chip seals on our priority roads due to issues with flying stones using graded aggregate and high float emulsion. • Public complaints.
Solution! • Rapid set emulsion, clean uniform aggregate. • 2014 test site, 6 different treatments. • Consultant from Alberta
6 Treatments Were Tested: 1.
Microsurfacing
2.
Cape-Seal
3.
Chip Seal (In-House)
4.
Fiber Mat
5.
Uniform (Single Aggregate)
6.
Racked-In
7.
Untreated
Results from Test Site • Rapid set polymer modified performed better in cracking, racked-in performed slightly better than single sized aggregate.
Challenges • Some people internally thought aggregate would be very expensive. • Some reluctance to contract out chip seal. • Some question effectiveness of chip seal on busy road.
2017 Chip Seal Contract • Used Alberta specifications, used in test project. • Warranty based, one year.
ASTM
1/2” 3/8” No.4 No.16
No.200
Contract #1 • ~50km, 31 mi • 3 sections, AADT from 4000 to 1500 • Contractor MSO (experienced from Ontario)
Design • 1.8 l/m2 (0.40 gal/yd2), test section was 2.0 l/m2 (0.44 gal/yd2) • No fog seal • Granite source aggregate
More Money $$ Contract 2 • • • •
150 km ~ 90 mi Specified slightly smaller aggregate Try fog seal on some sections Inexperienced contractor
Result • We like the fog seal so far, less flying stones, better appearance. • With limestone aggregate, have to watch to make sure application rate isn’t too high, dusty.
Changes In Project Selection • Past, condition based, reactive. Segment had to have some cracking to be considered a good candidate for chip seal. >15% extent
Current • Based on age and treatment history, if no treatments in last 7 years consider chip seal if good ride and rut. • IRI threshold ~1.9 m/km (120in/mi), ideally
