Presentation on theme: "Mix Design & Rejuvenators"— Presentation transcript:
1 Mix Design & Rejuvenators Grant Wollenhaupt & Jennifer BreuerMix Design & RejuvenatorsThis presentation demonstrates the new capabilities of PowerPoint and it is best viewed in Slide Show. These slides are designed to give you great ideas for the presentations you’ll create in PowerPoint 2010!For more sample templates, click the File tab, and then on the New tab, click Sample Templates.
2 1 2 Issues with Current Designs Cracking Raveling How do we fix these issues?
4 Cracking Causes Block Cracking - Old and dried out mix Mix was placed to dryFine aggregate with absorptionFatigue Cracking –Excessive loadingWeak surface, base, or subgradeThis surface or basePoor drainageAny combo from above
5 Cracking Causes Thermal Cracking- Reflective Cracking – Incorrect binder gradeSevere climatic changesReflective Cracking –Differential movement between asphalt and concrete layers
6 CRACKING Underlying cracking problem? Mix was placed to dry High absorption on some local aggregatesWeak base mixturesPoor drainageIncorrect binder gradesCRACKING
8 Raveling Causes? Asphalt Binder has hardened excessively Poor Quality MixtureBroken Bond between aggregate and asphaltOXIDATIONWater / TrafficRaveling
9 ISSUE SUMMARY Dry Mix Poor Base / Subgrade Drainage Inadequate binder gradeIncreased oxidationPoor construction
10 Environmentally responsible Recycled MaterialsHuge 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.Cost SavingsEnvironmentally responsible
11 BEST PRACTICES WITH RECYCLE QUESTION: Can recycling can be done responsibly and still provide performance as well as cost effectiveness?ANSWER: YES with design changes and rejuvenators
12 UNDERSTANDING YOUR INPUTS The key to effective design is understanding the products you are incorporatingAggregateRAPRASLiquid BinderAdditives
13 REJUVENATORS Hot Topic Rejuvenation – to restore youthful vigor; make young againSoftening Agent – substance added to a textile in finishing to give a softer handle
14 ? Exposure Time Temperature How much time do we have? 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?ExposureTimeTemperatureHow much time do we have?
15 Where does oxidation occur? Asphalt Storage TemperaturesMixing Temperatures at PlantSilo TimeUV and Oxygen Exposure
29 SUMMARYRecycle 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
30 Grant Wollenhaupt email@example.com www.researchtoroads.com QuestionsGrant Wollenhaupt