Download presentation
Presentation is loading. Please wait.
1
Andy Naranjo, P.E. Construction Division
Txdot and Fly Ash Andy Naranjo, P.E. Construction Division
2
TxDOT Concrete Stats Concrete Consumption Per Year TxDOT consumes approximately 150,000 to 200,000 tons of fly ash annually
3
CRCP Stats Lane Miles of Concrete Pavement Per Year
4
Class F Fly Ash Class C Fly Ash
5
Durability Requirements
Premature Deterioration: ASR, DEF, SRC TxDOT relies heavily on fly ash for mitigation these type of distresses High Performance Concrete: Typically required in coastal and North Texas Concrete Mix Options 1-4: All rely on SCM to meet requirements Fly ash only locally available option Small amount of Silica Fume used in Panhandle Permeability: State mandate to use brine solution as deicing material Mass Concrete Placements High volume fly ash mixes needed to reduce peak temperatures during curing large concrete elements
6
Air Entrainment Effective Freeze-Thaw Cycles
10 Dallam Sherman Hansford Ochiltree Lipscomb Hartley Moore Hutchinson Roberts Hemphill Oldham Potter Carson Gray Wheeler Deaf Smith Randall Armstrong Donley Collings- woth Parmer Castro Swisher Briscoe Hall Childress Bailey Lamb Hale Floyd Motley Dickens King Knox Cochran Hockley Lubbock Crosby Garza Lynn Terry Yoakum Gaines Dawson Borden Scurry Fisher Jones Kent Stonewall Haskell Throck- morton Baylor Wilbarger Wichita WICHITA FALLS Clay Archer Young Jack Howard Mitchell Nolan Taylor Callahan Eastland Glasscock Sterling Coke Runnels Shackelford Reagan Irion Montague Cooke Grayson Fannin Lamar Delta Red River PARIS Bowie Wise Denton Collin Hunt Hopkins Rains Wood Upshur Marion Cass Titus Morris Camp ATLANTA Harrison Smith Gregg Van Zandt Henderson TYLER Rusk Panola Anderson Cherokee Nacogdoches Freestone Dallas DALLAS Rockwall Stephens Palo Pinto Parker Tarrant Kaufman Shelby San Augustine Sabine Houston LUFKIN Angelina Tyler Polk Trinity Jasper Newton San Jacinto Walker Leon Navarro Ellis Hardin FORT WORTH Erath Hood Johnson Somer -vell Hill Bosque Mc Lennan Hamilton Coryell Bell Falls WACO Limestone Robertson Madison Milam Brazos Grimes Burleson BRYAN Washington Lee Austin Fayette Harris Montgomery Liberty BEAUMONT Orange Jefferson Chambers Galveston HOUSTON Fort Bend Brazoria Matagorda Wharton Colorado Lavaca Gonzales Dewitt YOAKUM Jackson Victoria Calhoun Waller Goliad Bee Refugio Aransas Karnes Live Oak Jim Wells San Patricio Nuceces CHRISTI CORPUS Kleberg Kenedy Willacy Hidalgo Brooks Jim Hogg Zapata Starr PHARR Duval Webb LAREDO La Salle Dimmit Zavala Frio Atascosa Mc Mullen Guadalupe Wilson Bexar Medina Uvalde Real Bandera Kerr Kendall Gillespie Blanco Kinney Maverick SAN ANTONIO Edwards Sutton Kimble Mason Llano Burner Williamson Trayis AUSTIN Bastrop Hays Caldwell Comal Brown Comanche BROWNWOOD Coleman Mills Mc Culloch San Saba Lampasas Concho Menard SAN ANGELO Schleicher Tom Green Andrews Martin Midland Pecos Ector Crane Ward Winkler Loving Crockett ValVarde Upton Terrell Reeves Culberson JeffDavis Brewster Presidio Hudspeth El Pasd EL PASO ODESSA LUBBOCK AMARILLO ABILENE Cottle Foard Hardeman CHILDRESS Franklin Effective Freeze-Thaw Cycles Below 17°F for more then 5 hours with moisture present Unburnt/Activated Carbon Primarily an issue for North Texas Fly Ash or Air? 5 1 10 5 1 2014 Spec changed the default for air entrainment. Only air entrain when shown on the plans No specified air content listed Must use an air entraining agent
7
Plant/Seasonal Outages
Unusually long outages can delay project schedules TxDOT has made some mix design allowances for periods of fly ash shortages Trial batches waived Straight cement mixes High Performance Concrete Sticking to our guns on this in most regions (North Texas and Costal) Will consider non-HPC mixes in substructure not over bridge joint on case by case basis
8
TxDOT Concrete Sustainability
Mix Design Potential CO2 Reduction CO2 Equvialent (Passenger Vehichels) 520 lb/cy -- 20% SCM 15% 26,500 35% SCM 27% 47,500 OAG Mix 13% 23,000 OAG Mix w/20%SCM 22% 22,000 Type IL w/20% SCM 20% 35,300 Type IL w/35% SCM 30% 51,000 Project , “Evaluating Limestone Cements with >15% Limestone 20% and 30% limestone contents Previous research has shown synergy with Class C fly ashes. Primary use in paving concrete Potential Reduction of CO2
9
Questions?
Similar presentations
