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Grant Wollenhaupt & Jennifer Breuer Mix Design & Rejuvenators.

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Presentation on theme: "Grant Wollenhaupt & Jennifer Breuer Mix Design & Rejuvenators."— Presentation transcript:

1 Grant Wollenhaupt & Jennifer Breuer Mix Design & Rejuvenators

2 Issues with Current Designs How do we fix these issues? 1Cracking 2Raveling

3 Cracking Fatigue – Block – Reflective - Thermal 1

4 Fatigue Cracking – 1.Excessive loading 2. Weak surface, base, or subgrade 3. This surface or base 4. Poor drainage 5. Any combo from above Block Cracking - 1.Old and dried out mix 2. Mix was placed to dry 3. Fine aggregate with absorption Cracking Causes

5 Reflective Cracking – 1. Differential movement between asphalt and concrete layers Thermal Cracking- 1.Incorrect binder grade 2. Severe climatic changes Cracking Causes

6 CRACKING Underlying cracking problem? Mix was placed to dry High absorption on some local aggregates Weak base mixtures Poor drainage Incorrect binder grades

7 2 Raveling Causes and Solutions

8 Raveling Causes? 1.Asphalt Binder has hardened excessively 2.Poor Quality Mixture 3.Broken Bond between aggregate and asphalt 4.OXIDATION 5.Water / Traffic

9 » Dry Mix » Poor Base / Subgrade » Drainage » Inadequate binder grade » Increased oxidation » Poor construction ISSUE SUMMARY

10 Huge push for recycled pavements in order to preserve the environment as well as reducing waste and aid in producing a cost effective mix to construct your roadways. Recycled Materials Cost Savings Environmentally responsible

11 QUESTION: Can recycling can be done responsibly and still provide performance as well as cost effectiveness? BEST PRACTICES WITH RECYCLE ANSWER: YES with design changes and rejuvenators

12 The key to effective design is understanding the products you are incorporating Aggregate RAP RAS Liquid Binder Additives UNDERSTANDING YOUR INPUTS

13 Rejuvenation – to restore youthful vigor; make young again Softening Agent – substance added to a textile in finishing to give a softer handle

14 Oxidation Asphalts exposure to oxygen begins a molecular process that causes new polar bonding sites. The increase of the polar sites allow molecules to shuffle looking for bonds that bring it to a thermodynamic stable state. “Self- assemblage” makes the bonds tighter resulting in a stiffer and brittle pavement ? How much time do we have?

15 Where does oxidation occur? Asphalt Storage Temperatures Mixing Temperatures at Plant Silo Time UV and Oxygen Exposure

16 Decreased Flexibility Brittle Binder POOR PERFORMANCE OXIDATION EFFECTS POOR WORKABILITY Decreased Elasticity Increased Stiffness/ Viscosity

17 » Re-Disperse the asphaltenes » Counter the stiffness of RAP/RAS » Help ratio of asphaltenes to resins and aromatics » Improve workability of the mix » Increase low temperature flexibility REJUVENATOR MARKET

18 Results TSRST Hamburg Results Virgin Binder PG Grading Mixture Grading SCB Results Texas Overlay

19 PG64-22 TRUE GRADE PG % HYDROGREEN PG % HYDROGREEN PG % HYDROGREEN Base Oil w/ Hydrogreen

20 T5RC WITH 30% RAPPG78-20 T5RC WITH 27%RAP/3% RASPG90-12 Field Data T5RC WITH 27%RAP/3% RASPG75-23 T5RC WITH 25%RAP/5% RASPG81-22 Add Rejuvenator

21 HAMBURG WHEEL-TRACKER Source: Laboratory Performance of Green Asphalt in Flexible Pavement SystemsLaboratory Performance of Green Asphalt in Flexible Pavement Systems

22 HAMBURG RESULTS Source: Laboratory Performance of Green Asphalt in Flexible Pavement SystemsLaboratory Performance of Green Asphalt in Flexible Pavement Systems

23 SCB Source: Laboratory Performance of Green Asphalt in Flexible Pavement SystemsLaboratory Performance of Green Asphalt in Flexible Pavement Systems

24 SCB RESULTS Source: Laboratory Performance of Green Asphalt in Flexible Pavement SystemsLaboratory Performance of Green Asphalt in Flexible Pavement Systems

25 TSRST Source: Laboratory Performance of Green Asphalt in Flexible Pavement SystemsLaboratory Performance of Green Asphalt in Flexible Pavement Systems

26 TRST RESULTS Source: Laboratory Performance of Green Asphalt in Flexible Pavement SystemsLaboratory Performance of Green Asphalt in Flexible Pavement Systems

27 TEXAS OVERLAY Source: FHWA/TX-14/ FHWA/TX-14/

28 $$$$$$$

29 Recycle is necessary to maintain roads under current budget To uphold quality of the recycled mixes, rejuvenators are a necessity Design changes are necessary to increase effective binder in mix Final product must be fairly evaluated SUMMARY

30 Grant Wollenhaupt Questions


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