Presented by Brian Malmberg, P.E.
INTRODUCTION INTRODUCTIONINTRODUCTION INTRODUCTIONINTRODUCTION INTRODUCTIONINTRODUCTION INTRODUCTION
375 miles of limerock roads
Low volume local roads are not cost
effective to pave with permanent surface at current funding levels
at current funding levels
Fugitive dust generated by limerock roads can be an nuisance issue
DUST ABATEMENT DUST ABATEMENTDUST ABATEMENT DUST ABATEMENTDUST ABATEMENT DUST ABATEMENTDUST ABATEMENT DUST ABATEMENT
Particles passing No. 200 sieve
Particles form binder in road surface
Provide agglomeration of particles
Adhere/bind the surface materials
Adhere/bind the surface materials together
Increase the density of the road material
DUST SUPPRESSANTS DUST SUPPRESSANTSDUST SUPPRESSANTS DUST SUPPRESSANTSDUST SUPPRESSANTS DUST SUPPRESSANTSDUST SUPPRESSANTS DUST SUPPRESSANTS
Dust Suppression Category
Typical Suppressants Selection for Review
Water Water Minimal effective duration
Water Absorbing Products Magnesium Chloride Calcium Chloride
Not commonly found in FL Selected for further review Organic Petroleum Products Emulsified Asphalt (sand seal) Selected for further review
Organic Nonpetroleum Products Animal fats, lignosulfonate, Cost prohibitive for large area Organic Nonpetroleum Products Animal fats, lignosulfonate,
vegetable oil
Cost prohibitive for large area applications
Electrochemical Products Enzymes, ionic products, sulfonated oils
Cost prohibitive for large area applications
Synthetic Polymer Products Polyvinyl acetate, vinyl acrylic Cost prohibitive for large area applications
Clay Additives Bentonite, Montmorillonite Long term constructability Issues, Environmental concerns
CALCIUM CHLORIDE CALCIUM CHLORIDECALCIUM CHLORIDE CALCIUM CHLORIDECALCIUM CHLORIDE CALCIUM CHLORIDECALCIUM CHLORIDE CALCIUM CHLORIDE
Classified as a salt
Deliquescent and Hygroscopic Properties
Applied at 1 to 1.5 lbs/sq. yd.
Scarify, apply, grade, compact
Scarify, apply, grade, compact
Reduces grading to 3 month cycle
Disadvantages: slippery when wet, vehicle corrosion, degradation of nearby vegetation, potential water pollution
EMULSIFIED ASPHALT EMULSIFIED ASPHALTEMULSIFIED ASPHALT EMULSIFIED ASPHALTEMULSIFIED ASPHALT EMULSIFIED ASPHALTEMULSIFIED ASPHALT EMULSIFIED ASPHALT
Emulsified asphalt w/ sand coat
Specialized equipment to apply
Forms solid surface and seals roadway
Reduces grading to 4 month cycle
Reduces grading to 4 month cycle
Disadvantages: Must be torn up and completely reapplied at each cycle;
potential spills or leaching if not allowed to cure
SCARIFY & REGRADE ROAD SCARIFY & REGRADE ROAD SCARIFY & REGRADE ROAD SCARIFY & REGRADE ROAD SCARIFY & REGRADE ROAD SCARIFY & REGRADE ROAD SCARIFY & REGRADE ROAD SCARIFY & REGRADE ROAD
APPLY SUPPRESSANT APPLY SUPPRESSANTAPPLY SUPPRESSANT APPLY SUPPRESSANTAPPLY SUPPRESSANT APPLY SUPPRESSANTAPPLY SUPPRESSANT APPLY SUPPRESSANT
FINAL GRADE & COMPACT FINAL GRADE & COMPACTFINAL GRADE & COMPACT FINAL GRADE & COMPACTFINAL GRADE & COMPACT FINAL GRADE & COMPACTFINAL GRADE & COMPACT FINAL GRADE & COMPACT
COST ANALYSIS COST ANALYSISCOST ANALYSIS COST ANALYSISCOST ANALYSIS COST ANALYSISCOST ANALYSIS COST ANALYSIS
Product/
Material
Limerock Material
Cost,
$/mile/year
Suppressant Cost,
$/mile/year
Grading Cycles per
Year
Grading Cost,
$/mile/year
Total Cost,
$/mile/year Crushed
Limestone $2,275.00 $0.00 8 $239.33 $4,189.67
Calcium
Chloride $1,137.50 $4,375.00 4 $239.33 $6,469.83
Chloride $1,137.50 $4,375.00 4 $239.33 $6,469.83
Emulsified
Asphalt $568.75 $4,320.00 3 $4,320.00 $13,528.75
Gorilla-Snot $682.50 $11,314.29 2 $239.33 $23,789.74
Soiltac $682.50 $15,027.69 1 $239.33 $15,949.53
Calcium chloride quote
Calcium chloride quote –– South Eastern Road TreatmentSouth Eastern Road Treatment Polymer quotes
Polymer quotes –– SoilworksSoilworks LLCLLC
CONCLUSION CONCLUSIONCONCLUSION CONCLUSIONCONCLUSION CONCLUSIONCONCLUSION CONCLUSION
Periodic limerock replacement and grading is most economical
Calcium chloride is most economical dust suppressant but would incur
dust suppressant but would incur additional costs when compared to current method
Roads under 100 vpd are not cost effective to treat w/ dust suppressant
COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS
20 Foot Wide Roadway Paving Estimates 20 Foot Wide Roadway Paving Estimates
ASPHALT PAVEMENT (Cost per mile of Roadway)
Description Unit Type Unit Cost Quantity Total Cost
Prepare Limerock base for paving SY $1.90 11,733 $22,293.33
Bituminous Prime Coat SY $0.50 11,733 $5,866.67
1-3/4" FC-9.5 Asphalt ton $80.00 1,129 $90,346.67
Sub-Total: $118,506.67 35% contingency for permitting, additional limerock & swale work Total: $159,984.00
CHIP SEAL SURFACE TREATMENT (Cost per mile of Roadway)
Description Unit Type Unit Cost Quantity Total Cost
Prepare Limerock base for paving SY $1.90 11,733 $22,293.33
Double Course Chip Seal SY $3.90 11,733 $45,760.00
Fog Seal SY $0.30 11,733 $3,520.00
Sub-Total: $71,573.33 35% contingency for permitting, additional limerock & swale work Total: $96,624.00
ESTIMATED TOTAL COUNTY PAVING COST
Asphalt Paving Cost $59,994,000
Chip Seal Application Cost $36,234,000
*Approximately 375 miles of limerock roads in Hernando County.
COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS COMPARISON COSTS
Yearly Comparison Cost Yearly Comparison Cost
PRODUCT/MATERIAL TOTAL COST, $/MILE/YEAR
Crushed Limestone $4,189.67
Calcium Chloride $6,469.83
Gorilla-Snot $23,789.74
Soiltrac $15,949.53
1-3/4” Asphalt Pavement $15,998.40
1-3/4” Asphalt Pavement $15,998.40
Double Chip Seal Surface Treatment $13,803.43
ASSUMPTIONS:
- South Eastern Road Treatment: 3,500 gallons to treat 1 mile, 20' wide, @ $1.25/gallon = $4375 - Soiltac is 1 gal/65 sf with 1:6 dilution, 275 gallon tote cost $2543.75, 12 month duration
- Gorilla-Snot is 1 gal/35sf with 1:3 dilution, 275 gallon tote cost $1,031.25, 6 month duration - Assume 10 year life-span on asphalt pavement
- Assume 7 year life-span on double chip seal pavement
REFERENCES REFERENCESREFERENCES REFERENCESREFERENCES REFERENCESREFERENCES REFERENCES
Bolander, P., & Yamada, A. (1999). Dust palliative selection and application guide. United
States Department of Agriculture, Forest Service. Washington, DC.
Brown, G. M. & Haliburton, T. A. (1984). Road dust control with calcium chloride. Vermont
Local Roads Program Fact Sheet. Colchester, VT: Saint Michael’s College.
CPWA, (2005). Dust control for unpaved roads, a best practice by the national guide to
sustainable municipal infrastructure. Canadian Public Works Association, http://www.infraguide.ca/lib/Db2File.asp?fileid=4555, accessed on April 1, 2011.
FDOT, (2010). Standard specifications for road and bridge construction, Florida Department of Transportation. Tallahassee, FL.
Lohnes, R.A. & Coree, B.J. (2002). Determination and evaluation of alternate methods for
managing and controlling highway-related dust. Final report for Iowa Highway Research Board
managing and controlling highway-related dust. Final report for Iowa Highway Research Board TR449. Iowa Department of Transportation, Department of Civil and Construction Engineering, Iowa State University, Ames Iowa.
Morgan, R. J., Schaefer, V.R., & Sharma, R. S. (2005). Determination and evaluation of alternate
methods for managing and controlling highway-related dust, Phase II demonstration project. Final report for Iowa Highway Research Board TR506. Iowa Department of Transportation, Department of Civil and Construction Engineering, Iowa State University, Ames Iowa.
Sanders, T. G., Addo, J. Q., Ariniello, A., & Heiden, W. F. (1997). Relative effectiveness of road dust suppressants. Journal of Transportation Engineering, Sept/Oct 1997.