CIVIL ENGINEERING APPLICATIONS OF TIRE DERIVED AGGREGATE

CIVIL ENGINEERING APPLICATIONS OF TIRE DERIVED AGGREGATE

Dana N. Humphrey, Ph.D., P.E.Professor of Civil Engineering

University of Maine

Presented to:CIWMB Waste Tire Forum

March 9, 2006

Dana N. Humphrey, Ph.D., P.E.Professor of Civil Engineering

University of Maine

Presented to:CIWMB Waste Tire Forum

March 9, 2006

Tire Derived Aggregate – TDA

Why use TDA?Why use TDA?• TDA has properties that civil engineers TDA has properties that civil engineers

needneed• Lightweight (1/3 soil)Lightweight (1/3 soil)• Low earth pressure (1/2 soil)Low earth pressure (1/2 soil)• Good thermal insulation (8 times Good thermal insulation (8 times

better)better)• Good drainage (10 time better)Good drainage (10 time better)• CompressibleCompressible• Vibration damping

Why use TDA?Why use TDA?• TDA is often TDA is often cheapestcheapest

alternative if you need their alternative if you need their unique propertiesunique properties

Why use TDA?Why use TDA?• Can use lots of tires!!!Can use lots of tires!!!

– 75 tires per C.YD. of TDA fill75 tires per C.YD. of TDA fill– 600,000 tires for Dixon Landing 600,000 tires for Dixon Landing

Interchange, Milpitas, CAInterchange, Milpitas, CA– 75,000 for vibration damping layer in San 75,000 for vibration damping layer in San

Jose, CAJose, CA– 75,000 for retaining wall backfill in 75,000 for retaining wall backfill in

Riverside, CARiverside, CA– 2 million for highway embankment in 2 million for highway embankment in

Sabatus, MaineSabatus, Maine

Civil Engineering Applications Civil Engineering Applications - United States vs. California -- United States vs. California -

• Uses 21% of tires in U.S.Uses 21% of tires in U.S.

• Uses 5% of tires in CaliforniaUses 5% of tires in California

Range of civil engineering Range of civil engineering applicationsapplications

• Lightweight fill for highway Lightweight fill for highway embankmentsembankments

• Retaining wall backfillRetaining wall backfill• Vibration damping layers for rail linesVibration damping layers for rail lines• Insulation to limit frost penetrationInsulation to limit frost penetration• Drainage layers for landfillsDrainage layers for landfills• Drainage layers for on-site wastewater Drainage layers for on-site wastewater

treatment systems (A.K.A. septic tanks)treatment systems (A.K.A. septic tanks)

Specifications• Type A – drainage, insulation & vibration

damping– 100% passing 4-in. sieve– Minimum of 90% passing 3-in. sieve– Maximum of 5% passing 4.75-mm (no. 4) sieve

• Type B – lightweight fill– 100% smaller than 18-in. max. dimension– 90% smaller than 12-in. max. dimension– Maximum of 50% passing 3-in. sieve– Maximum of 25% passing 1.5-in. sieve– Maximum of 1% passing 4.75-mm (no. 4) sieve

Dixon Landing Interchange

• PROBLEM: Embankment Constructed on Bay Mud

• SOLUTION: Use TDA for the core of the embankment

• CHEAPEST SOLUTION: Caltrans saved $470,000

Typical Cross Section

Unloading TDA

Spread with bulldozer

Compact with 10-ton roller

Conventional Lightweight Fill

Unit Costs

• Cost for common borrow = $7.48/yd3

• Placement costs of TDA (including geotextile) = $3.74/yd3

• Purchase & delivery costs of TDA (paid by CIWMB) = $23.66/yd3

• In-place cost for TDA = $27/yd3

• In-place cost for lightweight aggregate = $50/yd3

Cost Savings

• Cost savings to CALTRANS with TDA provided at no cost by CIWMB = $477,000

• Cost savings to state less purchase price of TDA = $230,000

Why use TDA for retaining wall backfill?

• Low unit weight (50 pcf)

• Free draining (k > 1 cm/s)

• Good thermal insulation (8 x better than soil)

• 75 tires per YD3!

Rt. 91 Wall in Riverside, CA

• Freeway widening

• Objective: show that reduced earth pressures can reduce overall wall construction costs

• Length: 260 ft

• Tires used: 75,000 PTE

Rt. 91 wall cross section

Compacting TDA

Potential Future Savings for Walls

• Lower pressure on wall less rebar

• Potential reduction = 28 tons/100 ft

• Potential cost savings = $13,000/100 ft

Vasona Light Rail Project

Vasona Light Rail Project

Vasona Light Rail ProjectDesign

• 12-in. ballast stone

• 12-in. subballast gravel

• 12-in. of TDA wrapped in geotextile

Vasona Light Rail ProjectMonitoring

Vasona Light Rail ProjectCost Savings

• Cost of conventional track = $100 per track-ft

• Cost of track with TDA vibration mitigation = $121 per track-ft

• Cost of floating slab vibration mitigation = $600-1000 per track-ft

• Cost savings = $479-$879 per track-ft• Total savings = $1 to $2-million

Future of TDA in California

• Two wall projects Spring/Summer, 2006• Caltrans HQ requires TDA as first

choice for lightweight fill• Need to develop more projects at

municipal/county level• Need more processors that can

efficiently make Type B TDA• Significant potential for growth

QUESTIONS?