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Task 4- Data Analysis. Task 4-Development of FDR Mix Design Guide. The objective of this task is to develop a mix design procedure for the various types of FDR Determine what works and what does not work Each type of FDR has separate mix design. Types of FDR. Unstabilized
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Task 4-Development of FDR Mix Design Guide • The objective of this task is to develop a mix design procedure for the various types of FDR • Determine what works and what does not work • Each type of FDR has separate mix design
Types of FDR • Unstabilized • Mechanically stabilized: add virgin aggregate • Stabilized FDR with Portland Cement • Stabilized FDR with Fly Ash • Stabilized FDR with Asphalt Emulsion • Stabilized FDR with Asphalt Emulsion with 1% Lime • Stabilized FDR with Foamed Asphalt with 1% Portland Cement
Composition of FDR • Source: Good and Poor • Quality: Dirty and Clean • RAP: 0, 25, 50, and 75%
Mix design Issues • Strength: • Mr and CBR for unstabilized • UC for cement and fly ash stabilized • TS for foamed and emulsion stabilized • Moisture Susceptibility • Tube Suction and ASTM D559 • For cement and fly ash stabilized • AASHTO T-283 • for foamed and emulsion stabilized
Mix Design Issues • What works and what does not • What criteria to implement • Repeatability and reliability • Does the measurement make engineering sense
Unstablized FDR • RAP 25 and 50% content did not significantly impact the Mr • The 75% RAP improved the Mr of the Poor source • Relationship between Mr and CBR is un-reliable for FDR: Use Mr
Mix Design Criteria • FDR+PC & FDR+FA • Dry UC: 300 – 400 psi • Tube Suction: max 9 • FDR+Foamed & FDR+Emulsion • Dry TS at 77F: min 30 psi • TS Ratio: min. 70%
Stabilized with PC • UC strength between 300 and 400 psi is achievable in most cases • Higher UC with higher PC content in all cases • Variability of the UC test is acceptable • Tube Suction test maybe applicable
Stabilized with FA • UC strength between 300 and 400 psi is achievable except for the Poor-Dirty material • Higher UC with higher FA in most cases • Variability of the UC is acceptable • Tube Suction test maybe applicable
Stabilized with Emulsion • Could not design the clean materials: too little fines • The TS is a good indicator • The repeatability of the TS is very good • Lime was effective
Stabilized with Foamed Asphalt • Could not design without the PC • The TS is a good indicator • The repeatability of the TS is very good
Task 5 – Development of Standard Laboratory testing Method • Be consistent with AASHTO Design Guides • AASHTO 1993 • AASHTO MEPDG
Task 5 – Development of Standard Laboratory testing Method • Unstablised: • Resilient modulus (Mr) • FDR+PC & FDR+FA: • Modulus of Rupture (MR) • FDR+Foamed & FDR+Emuslion: • Dynamic Modulus (E*)
Dynamic Modulus (E*) • |E*| master curve: Modulus of HMA at any combination of loading rate & temperature . = 0sin(ωt) 0 Stress Time time shift = / = 0sin(ωt-) 0 Strain |E*| = σ0/ε0 Time