The Texas Experience With Crumb Rubber Dale A. Rand, P.E.
CRM Hot Mix Jobs Constructed in 2001 Odessa: CRM-CMHB, SH 191 in Ector Co. ~12,000 tons Odessa: PFC, I-20 in Midland Co. ~22,500 tons Abilene: PFC, I-20 in Howard Co. ~14,000 tons El Paso: PFC, US 90 in Presidio Co. ~35,000 tons
Texas Strategies Rubber Crack Seal Hot Asphalt Rubber Seal or Underseal Crumb Rubber Modified Permeable Friction Course Crumb Rubber Modified HMAC
Texas Experience With Crumb Rubber Crack Seal Over 4 million pounds of crack sealant is used, nearly all of it crumb rubber modified.
Hot Asphalt Rubber Seal or Underseal Low volume, structurally sound but severely cracked pavements
Texas Experience with AR Seal Coat First use was in 1976 in Bryan and El Paso districts Between 1976 and 1981, 850 miles of AR seal coat was placed By 1990, 2,000 lane miles of AR Seal Coat was placed More than 20 districts have placed AR Seal Coat since 1976 in 70 counties
Seal Coat - US 90, near Big Bend National Park
US 90, crack disappearing in 10 year old Seal Coat
Eight year old Seal Coat
5 Year Old Seal Coat - IH-10 near Van Horn
Not all AR Seal Coats Turned out good Grade 4 Seal Coat
Another bleeding Seal Coat
Performance of AR Seal Coat Experience has mostly been satisfactory Good construction practices are a must! - Clean or pre-coated aggregate - Chip spreader staying close to distributor - Adequate curing of AR - Correct binder shot rate and aggregate rate
Crumb Rubber Modified (CRM) Permeable Friction Course (PFC) High volume, structurally sound pavements with poor wet weather skid performance
Porous Friction Course PFC Improves Safety By: Draining water away from the mix Reducing Hydroplaning Reducing splash and spray Improving wet pavement friction Improving surface reflectivity Reducing traffic noise
PFC in France
8 year old PFC in East Texas with Crumb Rubber, in the rain (no reflective cracking) (in 2000)
8 year old PFC in East Texas without Crumb Rubber, in the rain (in 2000)
6 Yr. Old Crumb Rubber PFC Odessa IH-20 First Job (Limestone) (in 2000)
Odessa IH-20 After 6 years (in 2000)
5 Yr. Old CRM PFC Odessa IH-20, Second job (rhyolite) (in 2000) Odessa, 5 years old
Job 3, Odessa IH-20, Less than 1 year old (in 2000)
Job 3, Odessa IH-20, Less than 1 year old (in 2000)
IH 20 EB - January 2002
IH 20 EB - January 2002
IH 20 EB - January 2002
IH 20 EB - January 2002
Summary of TxDOT Experience with Crumb Rubber Modified PFC Three jobs in Odessa District (IH 20) with excellent performance and no maintenance after 6,5, 1 year respectively (2000 data). One job in Lufkin District with excellent performance after 8 years (in 2000). 3 jobs constructed in 2001- Odessa, Abilene and El Paso Improved resistance to reflective cracking.
Crumb Rubber Modified HMAC (over a Hot Rubber Underseal) High volume, structurally sound, but severely cracked pavement
Texas Experience With CRM Hot Mix Before CMHB : Type F Project in Dalhart Good performance Type D project in Amarillo Premature Failure Type D project in Tyler Premature Failure Intersection in Tyler Good performance Type C in Lubbock Raveling Type D San Antonio IH 10..Premature Failure
Texas Experience With CRM Hot Mix After CMHB : CMHB-C in Abilene Good performance CMHB- C in Wichita Falls Good performance CMHB-C in Beaumont Good performance CMHB-C in Lufkin Base Failure CMHB-C in Lufkin Recently showed raveling and failure CMHB-C in Houston. Good performance CMHB-C in Odessa Good performance CMHB-F in Odessa. Good performance CMHB-F in Odessa.New
Beaumont, US 96: Built in 1994 Excellent performance, only few cracks in entire project
It is not all Good! Lufkin ; US 259 Nacagdoches County, Premature failure Air voids problems and possible base failure
CRM HMAC - US 385 Crane County Approximately 18 miles of US 385 with reflective cracking Selected areas milled, Type B HMAC place November 1997 Hot Rubber Seal applied 2 CRM HMAC laid April 1998
US 385 NB - August 2000
SH 191 - January 2002
SH 191 - January 2002 CRM HMAC
SH 191 - October 2001 CRM HMAC
SH 191 - January 2002
SH 191 - January 2002
SH 191 - January 2002
Benefits Resistance to reflective cracking due to elasticity of Crumb Rubber Modifier Resistance to aging (oxidation) of the asphalt film on aggregate particles Reduction of Maintenance Costs
Drawbacks Increased initial cost Contractor Comfort factor Handling difficulties
Summary of Strategies Low Volume, structurally sound, severely cracked pavement - Hot Asphalt Rubber Seal or Underseal High volume, structurally sound pavement with poor wet weather skid performance - Crumb Rubber Modified Plant Mix Seal High Volume, structurally sound, severely cracked pavement - Crumb Rubber Modified HMAC