Adding Value by Increasing the Use of Recycle (Part 2) Best Practices in RAP QC and Stockpile Management 36 th Annual Rocky Mountain Asphalt Conference and Equipment Show February 19, 2009 Denver, Colorado

By Tom Blair Director of Product Engineering – Asphalt Group Schmidt Construction/ Edw. C. Levy Co West 12 Mile Rd. Wixom, MI (248)

About the Edw. C. Levy Co.

LEVY IS ONE OF THE LARGEST RECYCLERS IN THE UNITED STATES, AUSTRALIA, AND THAILAND  WE HAVE BEEN RECYCLING SINCE  WE PROCESS MILLIONS OF TONS OF SLAG IN THE U.S. PER YEAR THAT IS SOLD AS CONSTRUCTION MATERIALS. WE ALSO RECOVER MORE THAN A MILLION TONS OF METALLICS PER YEAR THAT ARE RECYCLED BACK INTO THE STEEL MAKING PROCESS.  WE PROCESS AND UTILIZE NEARLY A HALF A MILLION TONS OF RECYCLED ASPHALT PAVEMENT (RAP) PER YEAR IN OUR ASPHALT MIXES AND HAVE BEEN USING RAP SINCE 1975.

Edw. C. Levy Co. – U.S.A. Operations in 11 States Asphalt Production & Paving Sand & Gravel Operations Quarry Operations Steel Mill Services Trucking Aggregate Docks – Sand, Gravel, Limestone, S.F. Slag, B.F. Slag Ready Mix Concrete

Asphalt Production & Paving

Colorado Asphalt Production & Paving Quarry Operations Sand & Gravel Operations Trucking

DELTA YARD COLORADO SPRINGS

RAP QUALITY CONTROL AND STOCKPILE MANAGEMENT

A BRIEF HISTORY OF USING RAP  1970’s – EXPERIMENTAL JOBS FROM 70% UP TO 100% RAP ANY WAY WE COULD. NO MIX DESIGNS – DUMP AND RUN. LOTS OF FAILURES  1980’s – CUT HOLES IN PLANTS AND HAD ENVIRONMENTAL ISSUES. LOTS OF STATES USED UP TO 50% RAP. LITTLE OR NO QUALITY CONTROL TESTING. NO VOLUMETRIC AND VERY LITTLE ACCEPTANCE TESTING. MANY MORE FAILURES. THEN RAP COLLARS INVENTED TO PROVIDE A BETTER WAY TO INTRODUCE RAP INTO THE PLANT  1990’s – BETTER PLANT DESIGNS FOR INTRODUCING RAP INTO THE PLANT. THEN COUNTERFLOW PLANTS DESIGNED TO USE HIGH PERCENTAGES OF RAP. VOLUMETRIC TESTING INTRODUCED. LOTS OF QUALITY CONTROL TESTING FOR VOIDS ACCEPTANCE JOBS. MORE QUALITY ASSURANCE TESTING. GOOD RAP MIX PERFORMANCE

A BRIEF HISTORY OF USING RAP (cont.)  LATE 1990’s TO THE PRESENT – EVEN BETTER ASPHALT PLANTS DESIGNED TO RUN HIGHER RAP PERCENTAGES YET BE EVEN MORE ENVIRONMENTALLY FRIENDLY. MORE EMPHASIS ON QUALITY CONTROL. TIGHTER ACCEPTANCE SPECIFICATIONS LIKE PWL. SUPERPAVE INTRODUCED. LOTS OF NEW RESEARCH ON MIXTURE PERFORMANCE AND RAP USE. EXCELLENT RAP MIX PERFORMANCE REMEMBER WHEN WE FIRST STARTED RECYCLING PAPER AND PLASTIC? THEY USED TOO HIGH OF A RECYCLED MATERIAL CONTENT AND THE PERFORMANCE WAS POOR. NOW THEY USE LESS RECYCLED MATERIAL CONTENT BUT PUT IT IN ALMOST EVERYTHING AND NO ONE KNOWS THE DIFFERENCE. SAME THING WITH AN ALUMINUM CAN OR YOUR NEW CAR. RAP ASPHALT MIXES CAN PERFORM BETTER THAN ALL NEW MATERIAL IF DONE CORRECTLY

THREE MAIN RULES FOR SUCCESSFUL RECYCLING OF ASPHALT PAVEMENTS

1. THE QUALITY OF THE PRODUCT MADE WITH RECYCLED MATERIALS MUST BE EQUAL TO OR BETTER THAN THE QUALITY OF THE ORIGINAL PRODUCT. “AS GOOD OR BETTER” DON’T USE TOO HIGH OF A RECYCLED MATERIAL CONTENT.

2. THE RECYCLED PRODUCT PRODUCED MUST BE COST EFFECTIVE. SOME DAY IT MAY BE ABLE TO COST MORE WHEN WE GET CREDIT FOR USING RECYCLED MATERIALS. THE GREAT THING ABOUT USING RECYCLED ASPHALT PAVEMENT (RAP) IS THAT IT LOWERS THE COST OF THE FINISHED PRODUCT AND CAN PROVIDE AS GOOD OR BETTER FINISHED PRODUCT THAN USING ALL NEW MATERIALS IF DESIGNED PROPERLY.

3. WE MAY NEED TO CHANGE SOME OF THE OTHER RAW MATERIALS WE USE WITH THE RECYCLED MATERIAL AND SOME OF OUR PROCESSES TO MEET THE FIRST TWO RULES. DON’T JUST SUBSTITUTE IN A RECYCLED MATERIAL WITHOUT DESIGNING FOR IT MOST OF THE TIME WHEN USING RAP WE NEED TO USE CLEANER AGGREGATES

SO – WHERE DO WE START?

RAW MATERIAL PILE MUST BE CLEAN  DO NOT ALLOW ANYTHING OTHER THAN BROKEN ASPHALT, RETURNED ASPHALT, CLEAN-OUT ASPHALT, OR MILLINGS IN THE RAP RAW MATERIAL PILE. WE ONLY HAVE ONE PILE – ALL GOOD.  CHECK TRUCKS DUMPING MATERIAL IN YOUR RAW MATERIAL PILE FOR CONTAMINATION AND REJECT THEM.

KEEP THE CRAP OUT MUST BE CONSTANTLY MONITORED DON’T WANT ANY TRASH, CONCRETE, BRICKS, CLAY, WOOD OR TOPSOIL IN THE RAP PILE SEND THE JUNK TO THE LANDFILL

KEEP THE RAW MATERIAL PILE BLENDED  SPREAD OUT PLANT CLEAN OUT MATERIAL, WASTED SILO MATERIAL, AND RETURNED MATERIAL SO THAT IT DOESN’T HARDEN INTO BIG CHUCKS. THIS MAKES IT HARD TO CRUSH AND CAN CAUSE POCKETS OF HIGH ASPHALT CONTENT FINISHED PRODUCT  BUILD THE RAW MATERIAL PILE IN LAYERS AND SPREAD OUT MILLINGS SO THAT THE PILE WILL BE UNIFORM IN MATERIAL TYPE WHEN CRUSHED

NOT TOO CONSISTENT

NICE RAW MATERIAL PILE

NOW WHAT DO WE DO WITH IT? CRUSHING, SCREENING, FRACTIONATING, RAW MILLINGS

SHOULD WE CRUSH OR SCREEN THE RAP? IS CRUSHING REALLY NECESSARY? WHAT IS THE COST DIFFERENCE? IF WE SCREEN IT, WHAT SIZE?

CRUSHING OR SCREENING THE RAP SHOULD DEPEND ON: THE SIZE OF THE MATERIAL IN YOUR RAW MATERIAL PILE CRUSHING BREAKS DOWN WEATHERED AGGREGATES AND ALLOWS DEBRIS TO BE REMOVED BIGGER IS CHEAPER, SMALLER IS MORE EXPENSIVE AND CREATES MORE FINES BUT BLENDS BETTER AND SEGREGATES LESS SCREENING SIZE DEPENDS ON THE TOP SIZE OF THE MIX IT IS GOING INTO. HOWEVER, SMALLER SIZES TRANSFER HEAT BETTER.

SHOULD WE FRACTIONATE IT? ADVANTAGES – LESS MOISTURE, LESS STOCKPILE MANAGEMENT, LESS SEGREGATION DISADVANTAGES – FINES TURN HARD UNLESS “JUST IN TIME CRUSHING”, WHAT TO DO WITH EXCESS FINES, NO STOCKPILE TO MINIMIZE VARIATIONS OR KEEP THE CRAP OUT, EXTRA FEEDER BINS, YARD SPACE, COST DIFFERENCE

SHOULD WE USE RAW MILLINGS? ADVANTAGES – CHEAPER DISADVANTAGES – POOR HEAT TRANSFER, MORE YARD SPACE, NO STOCKPILE TO MINIMIZE VARIATIONS AND SCREEN JUNK OUT, SOMETIMES DIFFICULT TO GET A MIX DESIGN IF MILLINGS ARE COMING FROM THE SAME JOB

CRUSHING  BLEND THE RAW MATERIAL PILE WHILE FEEDING THE CRUSHER. MOVE POCKETS OF MILLINGS OR CLEAN-OUT MATERIAL OUT OF THE WAY IF NECESSARY TO HELP KEEP CONSISTENCY OF THE FINISHED PRODUCT.  WORK A LARGE LOADING FACE OF THE RAW MATERIAL PILE TO FEED THE CRUSHER  MAKE SURE THE RAP CRUSHER IS CLEANING DEBRIS OFF HIS SCREEN REGULARLY TO KEEP IT OUT OF THE FINISHED PRODUCT PILE.  BUILD THE FINISHED PRODUCT PILE IN LAYERS. USE A DOZER OR A PROGRAMABLE STACKER

CRUSHING (cont.)  DON’T BUILD THE RAP FINISHED PRODUCT STOCKPILES TOO HIGH.  MAKE SURE SOMEONE TAKES SAMPLES OF THE FINISHED PRODUCT DURING CRUSHING FOR TESTING AT SET INTERVALS. ALSO, TAKE SOME RANDOM SAMPLES TO COMPARE RESULTS.  A GOOD RAP CRUSHER IS YOUR MOST VALUABLE RESOURCE IF HE BLENDS THE RAW MATERIAL AND FINISHED PRODUCT PILES UNIFORMLY AND KEEPS THE BAD MATERIAL AND JUNK OUT. THIS MATERIAL LIKE TOPSOIL, CLAY, TIRES, CONCRETE, BRICKS, AND WOOD MUST BE HAULED TO THE LANDFILL.

KEEP IT TESTED  TEST THE RAP DURING CRUSHING ONCE EVERY 1000 TONS OR MORE AS IT IS BEING PRODUCED  VERIFY PRODUCTION TEST RESULTS LATER WITH LOADING FACE SAMPLES DURING USE  GIVE FEEDBACK TO RAP CRUSHER DURING CRUSHING IF CONSISTENCY IS NOT BEING MET  TEST AND ADJUST THE VOLUMETRIC PROPERTIES OF THE MIX OFTEN TO ENSURE QUALITY

KEEP IT TESTED (cont.)  WATCH OUT IF USING THE IGNITION FURNACE FOR AC CONTENTS OF THE RAP. IT IS BEST TO VERIFY THE RESULTS ONCE IN A WHILE WITH SPLIT SAMPLE TESTING USING A SOLVENT EXTRACTION WITH A GOOD SOLVENT.  TO BE SUCCESSFUL, YOU PROBABLY WILL NEED INCREASED TESTING CAPABILITY FOR RUNNING RAP MIXES BECAUSE THEY CAN TAKE A LITTLE EXTRA WORK.

RAP MIX DESIGN HINTS  START WITH THE RAP AND DESIGN AROUND IT. USE CLEANER AGGREGATES IF NECESSARY TO MEET ALL THE SAME CRITERIA AS FOR VIRGIN MIXES.  MAKE SURE YOU KNOW ALL THE PROPERTIES OF THE RAP; AC CONTENT/STIFFNESS, GRADATION, SPECIFIC GRAVITY AND ABSORPTION, DELETERIOUS, PARTICLE SHAPE, AND ANGULARITY.  WATCH WHAT GRADE OF VIRGIN BINDER YOU SELECT. BUMPING THE TOP AND BOTTOM IS OFTEN TIMES TOO SOFT AND CAN RESULT IN SOFT MIXES. NEW RESEARCH SHOWS CHANGING GRADES OF VIRGIN ASPHALT IN RAP MIXES MAY NOT BE NECESSARY.

FEEDING THE PLANT  IF POSSIBLE, AVOID DOUBLE HANDLING THE FINISHED PRODUCT TO PREVENT SEGREGATION  USE AS BIG OF A LOADING FACE AS POSSIBLE ON THE FINISHED PRODUCT PILE TO FEED THE RAP BIN  LOAD OUT PERPENDICULAR TO THE DIRECTION THE STOCKPILE WAS BUILT IN  SMALLER SIZES OF SCALPER SCREENS ALLOW BETTER HEAT TRANSFER, DRYING, AND MIXING OF THE RAP WITH THE AGGREGATE AND AC.

FEEDING THE PLANT (cont.)  CALIBRATE THE RAP FEEDER OFTEN.  WATCH THE PERFORMANCE OF THE RAP FEEDER AND PREVENT BRIDGING OR FLOW PROBLEMS WITH THE FEEDER. LINE THE BINS.  MAKE SURE YOU HAVE THE CORRECT ASPHALT CEMENT CONTENT OF THE RAP ENTERED INTO YOUR PLANT CONTROLS

KEEP IT HOT  MAKE THE AGGREGATE HOT ENOUGH IN THE PLANT FOR GOOD DRYING AND HEAT TRANSFER TO OCCUR  DON’T RUN THE PLANT TOO FAST  MONITOR MOISTURE CONTENTS OF THE RAP OFTEN AND UPDATE THE PLANT CONTROLS  IF USING STIFFER ASPHALT CEMENTS, MAKE THE MIX HOTTER  WHEN IT IS WET OR COLD USE LESS RAP

TO KEEP IT PERFORMING BE CAREFUL IF KEEPING THE MIX OVERNIGHT. WATCH SILO STORAGE TIME AND FOR DELAYS ADD A LITTLE EXTRA ASPHALT CEMENT TO ACCOUNT FOR ABSORPTION IF THE MIX WILL BE STORED FOR AN EXTENDED PERIOD KNOW THE EFFECTS ON VOLUMETRIC PROPERTIES AND ADJUST ACCORDINGLY. DON’T BE AFRAID TO ADJUST THE MIX PROPERTIES DURING PRODUCTION. CONTROL THE VARIABILITY IN ALL PHASES OF THE PROCESS

HOW MUCH SHOULD WE USE? CAN WE CONTROL THE VOLUMETRIC PROPERTIES? CAN YOU GET THE VMA HIGH ENOUGH ABOVE THE MINIMUM IN THE DESIGN STAGE TO ACCOUNT FOR PLANT DEGRADATION AND ABSORPTION DURING PRODUCTION? WHAT ARE THE SPECIFICATION LIMITS? DO WE HAVE ENOUGH SUPPLY OF RAP? DO WE HAVE CLEAN AGGREGATES TO BLEND WITH THE RAP TO MEET VMA AND VOIDS?

HOW MUCH SHOULD WE USE? (cont.) WHAT ARE OUR PLANT LIMITATIONS? WHAT ARE OUR AIR PERMIT LIMITATIONS? IS THERE ANY OPERATIONAL RESISTANCE? IS THERE ANY CUSTOMER RESISTANCE? WHAT DO YOU FEEL COMFORTABLE WITH?

LET’S KEEP RAP THE NATIONS TOP RECYCLED MATERIAL

THANK YOU!

QUESTIONS?