Recycling with CRM. John D Angelo D Angelo Consulting, LLC Phone johndangelo@dangeloconsultingllc.com

Transcription

1 Recycling with CRM John D Angelo D Angelo Consulting, LLC Phone johndangelo@dangeloconsultingllc.com

2 Tire Rubber

3 Crumb Rubber Modifier There are several different processes used to with CRM. Dry process modification. Wet process. Terminally blended.

4 Crumb Rubber Modifier Tires are ground by different process and to different sizes. Ambient Grind Cryogenic Grind

5 CRM Sizes Rubber is delivered in different systems with supper sacks very prevalent. CRM comes in different sizes.

6 30 Mesh CRM

7 Blended Crumb Rubber Added To Plant at RAP Collar Dry process Georgia DOT

8 Crumb Rubber Modifier Ambient Grind Typically used for wet process and terminal blends. Cryogenic Grind Typically used for the dry process.

9 CRM blender

10 CRM Blender

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12 Inside Mixing Tank

13 Terminal Blend Rubber Rubber added to binder in a terminal and blended like polymer for shipment to mix plant. Requires agitation to prevent settlement.

14 Terminally Blended CR Binder Binder delivered and stored just like standard AC binders. Does require agitation to prevent settlement,

15 Differences in CRB process Terminal Blend Wet Process

16 Aluminum plates 150 mm (6 in) Overlay Tester Sample 38 mm (1.5 in) 2 mm (0.08 in) Ram direction Fixed plate Movable plate plate Sample size: 6 long by 3 wide by 1.5 high Loading: Continuously triangular displacement 5 sec loading and 5 sec unloading Definition of failure Discontinuity in Load vs Displacement curve Visible crack on surface

17 AR-OGFC Over 12.5H76 Side of AR-OGFC Sample (Before Test)

18 AR-OGFC Over 12.5H76 Side of AR-OGFC Sample (After Test)

19 AR-OGFC Over 12.5H76 Top of AR-OGFC Sample (After Test)

20 AR-OGFC & AR-GG for PCC Overlays Noise Pressure, db(a) AR-OGFC (11 Yrs Old) Vehicle Speed = 60 mph AR-OGFC (10 Yrs Old) OGFC MOGFC-1 (1 Yr Old) MOGFC-1 (4 Yrs Old) mm SP I-78 E (MP (1 Yr Old) 25.03) NJ 29 N (MP ) PCC I-78 E (MP 26.7) I-78 E (MP I-78 W (MP ) ) 7 to 10 db reduction in noise measurements!

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22 Mix Design Terminal blend CRM requires no design changes may have slightly higher binder content. Field blended CRM requires gap graded mix to allow room for rubber particles. Dry added CRM requires higher binder content curing time. Rubber is not counted as binder. Mixes may swell after compaction in molds and require cooling in molds to avoid damage.

23 Terminal Blend AR Superpave Mix Design N d = 75, P b = 5.3 % FHWA 0.45 Power Chart 12.5 mm Nominal Maximum Size Percent Passing Moderate Traffic Mix Sieve Size, mm

24 Asphalt Rubber OGFC

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26 Asphalt Rubber Gap Graded

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28 CRM Laydown and Compaction No special requirement/techniques May require more attention than conventional mixes Mix Workability - Stiffer Density Higher temps, more roller passes, heavier roller? Cooler temperatures Reduced compaction times Warm mix technologies can extend compaction times

29 CRM asphalt Use varies based on system. Dry process variable size CRM 1to 10% by weight of mix, coarse rubber with adjustments to mix gradation. Wet process 20 mesh CRM18 to 22% by weight of binder, blending and curing at mix plant. Terminal Blend 30 mesh or smaller CRM10 to 15% by weight of binder delivered to mix plant binder tank.

30 CRM Historically testing has been done with pen and vis. Viscosity was mostly rotational or vane shear.

31 Photomicrographs of CMCRA Transmitted and Fluorescent Light

32 Crumb Rubber Modifier How do CRM binders compare to PMA binders? Use SHRP performance binder testing to evaluate.

33 CRM blending study Six binders from various sources in the world. Smaller CRM size 10% added CRM High temperature blending.

34 10% CRM Blends Nynas, 250μm-210 C Total, 250μm-210 C Orlen, 250μm-210 C Exxon-Mobil, 250μm-210 C SJR, 250μm-210 C Shell, 250μm-210 C

35 CRM blending Study 10% CRM Asphalt ID SHRP PG MSCR PG Jnr % rec % Change Jnr Nynas, 250μm V % 79% Total, 250μm V % 66% Orlen, 250μm E % 71% Exxon-Mobil, 250μm V % 73% SJR, 250μm H % 102% Shell, 250μm H % 71%

36 CRM Blending Study Binder source effects CRM binder properties 10% CRM increased the binder grade by 2 steps 64S to 64V for most binders. One source only had 1 step increase in stiffness. Several blends would meet stress sensitivity, but not all.

37 ALF Test Sections 7 Asphalt Binders AZ CRM PG Control Air Blown SBS TX TBCR TP PG PG SBS Air Blown Fibers SBS TP

38 ALF TBCR binder testing PG grade Test Temp MSCR grade Jnr % Rec % Change Jnr 64C 64-28E C 70-28E

39 ALF PMA study TBCR binder would meet all MSCR binder requirements. Jnr and % Recovery met by ALF TBCR % change.1 to 3.2 Jnr also met.

40 ALF Test Sections Fatigue Cracking Cumulative Crack Length (m) Crack Length vs ALF Wheel Load Passes (Testing Condition: 19 o C & 16,600 lbs) Number of Load Passes L3S3 (Air Blown) L2S3 (Control) L5S3 (CR-TB) L6S3 (Terpolymer) L4S3 (SBS LG) L1S2 (CR-AZ)

41 High Temperature Binder Properties Comparing PG 76 Binders V PG 76 pmb1 Jnr 3.2 1/kPa 64C E 76 AR HB pmb2 30 mesh mesh E+ 30 mesh mesh 10% 60 mesh 15% G*/sinδ 76C

42 Effect of CRM on Low Temperature Grade Low Temp Continuous Grade Improved with rubber % 60M 15% 60m 10% 30M 15% 30M Low Temp Grade

43 CRM Binder CRM binder can be classified in the PG system and by the MSCR. New test procedure is being developed to test larger wet process asphalt rubber binders.

44 Development of New Test Procedures for Testing Larger Rubber Particles Standard Parallel Plate testing for Binders New Cup and Bob testing for Rubber Binders

45 Parallel Plate 2 mm gap largest rubber particle.5mm

46 Cup & Bob Top View 6 mm gap largest rubber particle 1.5 mm

47 Comparison of PMA to Dry CRM Mix Properties 12.5 mm Superpave dense graded mix N des = 65 25% RAP AC content = 5.10% PG asphalt GTR and TOR added as per GA DOT specification Comparison SBS-modified mix Identical mix design PG modified as per GA DOT specification

48 Hamburg Dry Condition Hamburg Rut Depth (mm) NuStar Loading Cycles PMA - STOA (Dry) CR - STOA (Dry)

49 Hamburg Wet Condition NuStar Hamburg Rut Depth (mm) Loading Cycles PMA - STOA (Wet) 13 CR - STOA (Wet) 14 15

50 Summary CRM binder is sensitive to crude source. Rubber size will effect test results. Particles should be ¼ gap size or less. Careful formulation is needed to meet all Jnr specs, but it can be done successfully. CRM Binders can be produced to meet PMA specs. CRM Dry Process is a mix modifier and is not the same as a PMB mix.

51 Recycling with CRM and other Byproducts CRM has been used successfully for many years. There are multiple approaches to using CRM each with its own requirements and issues.

52 Thank You