Materials 206: Handling RAP (Advanced) Contractor QC and Specifications

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2 Materials 206: Handling RAP (Advanced) Contractor QC and Specifications 38 th Annual Rocky Mountain Asphalt Conference and Equipment Show February 25, 2011 Denver, Colorado

3 By Tom Blair Director of Product Engineering Asphalt Group Schmidt Construction/ Edw. C. Levy Co.

4 About the Edw. C. Levy Co.

5 Asphalt Production & Paving

6 Asphalt Production & Paving

7 LEVY IS ONE OF THE LARGEST RECYCLERS IN THE UNITED STATES, AUSTRALIA, AND THAILAND WE HAVE BEEN RECYCLING SINCE WE PROCESS TEN MILLION 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.

8 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

9 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 MIXES CAN PERFORM AS GOOD OR BETTER THAN ALL NEW MATERIAL IF DONE CORRECTLY

10 THREE MAIN RULES FOR SUCCESSFUL RECYCLING OF ASPHALT PAVEMENTS

11 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. WE WANT IT TO LAST!

12 2. THE RECYCLED PRODUCT PRODUCED MUST BE COST EFFECTIVE.

13 COST EFFECTIVE RECYCLING ASPHALT BACK INTO ASPHALT MIXTURES IS ACTUALLY LESS EXPENSIVE THAN MAKING MIX WITH ALL NEW MATERIALS. LOTS OF OTHER MATERIALS ARE MORE EXPENSIVE TO USE THAN USING ALL NEW MATERIALS. MANY REQUIRE SUBSIDIES BEFORE THEY ARE USED AND MANY RESULT IN LOWER QUALITY FINISHED PRODUCTS THAN ALL NEW.

14 RAP Value per Ton Aggregate Value $9.00x0.955= $8.60 Asphalt Cement Value $500.00x0.045= $22.50 Total RAP Value per Ton = $31.10 Less Crushing and Handling Costs -$5.00 Remaining Value per Ton = $26.10 Mix Cost Savings 10% in Mix = $2.61/per mix ton 20% in Mix = $5.22/per mix ton 25% in Mix = $6.52/per mix ton

15 RAP Value per Ton Aggregate Value $9.00x0.955= $8.60 Asphalt Cement Value $500.00x0.045= $22.50 Total RAP Value per Ton = $31.10 Less Crushing and Handling Costs -$5.00 Remaining Value per Ton = $26.10 Agency Ownership Value When Used on Shoulders or as Aggregate Base -$9.00 Lost Value When Used on Shoulders or as Aggregate Base $17.10

16 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. MOST OF THE TIME WHEN USING RAP WE NEED TO USE CLEANER AGGREGATES WE MAY NEED TO RUN THE PLANT SLOWER AND HOTTER

17 SO - HOW CAN WE DESIGN AND ENGINEER THE PAVEMENT TO PERFORM AS GOOD OR BETTER THAN IT WOULD WITHOUT RAP?

18 KEEP THE MIX SPECIFICATIONS THE SAME AS THEY WOULD BE WITHOUT RAP KEEP IT CLEAN KEEP IT SMALL KEEP IT CONSISTENT KEEP IT HOT KEEP IT TESTED

19 KEEP THE MIX SPECIFICATIONS THE SAME DESIGN THE MIX WITH THE SAME AIR VOIDS, VMA, VFA, AC/FINES RATIO AS VIRGIN MIX DON T JUST SUBSTITUTE RAP INTO THE MIX WITHOUT A NEW MIX DESIGN!!! EVALUATE THE AGGREGATE PROPERTIES OF THE RAP AGGREGATE AND USE CLEANER BETTER QUALITY AGGREGATES TO MEET THE MIX DESIGN CRITERIA IF NECESSARY DO NOT USE WIDER TOLERANCES FOR ACCEPTANCE TESTING - USE VOIDS ACCEPTANCE

20 KEEP IT CLEAN DO NOT ALLOW ANYTHING OTHER THAN BROKEN ASPHALT, RETURNED ASPHALT, CLEAN- OUT ASPHALT, OR MILLINGS IN THE RAP RAW MATERIAL PILE. HAVE SIGNS MADE UP THAT SAY WE ACCEPT CLEAN BROKEN ASPHALT ONLY. VIOLATERS WILL LOSE DUMPING PRIVILEGES CHECK TRUCKS DUMPING MATERIAL IN YOUR RAW MATERIAL PILE FOR CONTAMINATION AND REJECT THEM

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22 WATCH THESE GUYS!

23 LOOK WHAT THEY SNUCK IN!

24 MORE JUNK

25 IF TREES ARE GROWING OUT OF YOUR RAP PILE, IT IS PROBABLY TOO DIRTY!

26 KEEP IT CLEAN (cont.) MAKE SURE THE RAP CRUSHER IS CLEANING DEBRIS OFF HIS SCREEN REGULARLY TO KEEP IT OUT OF THE FINISHED PRODUCT PILE. 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. DON T GET CHEAP WITH THE RAP CRUSHER. WE ARE ALWAYS TRING TO SAVE A NICKEL AND THIS WILL TRANSLATE INTO THE TYPE OF SERVICE HE GIVES YOU.

27 KEEP IT SMALL PICK THE RIGHT SIZE TO CRUSH RAP AT - BALANCING COST WITH HOW MANY MIXES IT CAN BE UTILIZED IN. SMALLER SIZES CAN HAVE LESS VARIABILITY, LESS SEGREGATION, AND TRANSFER HEAT BETTER. SMALLER SIZES SCREEN OUT MORE DEBRIS DURING CRUSHING. SMALLER SIZES OF SCALPER SCREENS ALLOW BETTER HEAT TRANSFER, DRYING, AND MIXING

28 4 GRIZZLY

29 1 ½ AND ¾ TWIN DECK SCALPER SCREEN

30 KEEP IT CONSISTENT 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 WORK A LARGE LOADING FACE OF THE RAW MATERIAL PILE TO FEED THE CRUSHER

31 OPPS!

32 NOT SPREADING OUT THE PLANT CLEAN OUT MATERIAL

33 NOT TOO CONSISTENT OF A RAW MATERIAL PILE

34 NICE RAW MATERIAL PILE

35 KEEP IT CONSISTENT (cont.) 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. MAKE SURE SOMEONE TAKES SAMPLES OF THE FINISHED PRODUCT DURING CRUSHING FOR TESTING AT SET INTERVALS. ALSO, TAKE SOME RANDOM SAMPLES TO COMPARE RESULTS. BUILD THE FINISHED PRODUCT PILE IN LAYERS. USE A DOZER OR A PROGRAMABLE STACKER

36 KEEP IT CONSISTENT (cont.) 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

37 LOADING OUT PERPENDICULAR TO THE DIRECTION THE PILE WAS BUILT IN

38 LOADING OUT PERPENDICULAR TO THE DIRECTION THE PILE WAS BUILT IN

39 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 PLANT CONTROLS IF USING STIFFER ASPHALT CEMENTS, MAKE THE MIX HOTTER WHEN IT IS WET OR COLD USE LESS RAP

40 KEEP IT TESTED TEST THE RAP DURING CRUSHING ONCE EVERY 1000 TONS OR MORE AS IT IS BEING PRODUCED GIVE FEEDBACK TO RAP CRUSHER DURING CRUSHING IF CONSISTENCY IS NOT BEING MET VERIFY PRODUCTION TEST RESULTS LATER WITH LOADING FACE SAMPLES DURING USE TEST AND ADJUST THE VOLUMETRIC PROPERTIES OF THE MIX OFTEN TO ENSURE QUALITY ADD A LITTLE EXTRA ASPHALT CEMENT TO ACCOUNT FOR ABSORPTION IF THE MIX WILL BE STORED FOR AN EXTENDED PERIOD

41 SUMMARY GOOD CRUSHED, BLENDED, CLEAN RAP PILE GOOD PLANT, OPERATED PROPERLY MIX THOROUGHLY TO GET IT DRY, HOT, AND CONSISTENT GOOD MIX DESIGN MEET ALL PROPERTIES GOOD QUALITY CONTROL CONTROL VOLUMETRIC PROPERTIES. DON T JUST WATCH IF NECESSARY, ADD A LITTLE AC IF STORING THE MIX OVERNIGHT OR FOR LONG PERIODS TO ACCOUNT FOR ABSORPTION AND DON T FORGET TO KEEP IT HOT IN THE SILOS

42 HOW CAN WE DESIGN AND ENGINEER THE PAVEMENT TO PERFORM AS GOOD OR BETTER THAN IT WOULD WITHOUT RAP?

43 KEEP THE MIX SPECIFICATIONS THE SAME AS THEY WOULD BE WITHOUT RAP KEEP IT CLEAN KEEP IT SMALL KEEP IT CONSISTENT KEEP IT HOT KEEP IT TESTED AND IT WILL KEEP PERFORMING

44 LET S KEEP RAP THE NATIONS TOP RECYCLED MATERIAL

45 SOME OTHER ISSUES - CRUSHING, SCREENING, FRACTIONATING, RAW MILLINGS, HOW MUCH SHOULD WE USE?

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

47 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.

48 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

49 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.

50 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

51 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

52 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?

53 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?

54 THANK YOU!

55 QUESTIONS?