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IDOT Update. Eric E. Harm Assistant Chief Engineer IAAP - May 17, 2007. Materials Audit. Materials Audit. Office of Auditor General / KPMG Before 2004 (Laid-back) – MISTIC was good enough 2004-6 (Under a microscope) – source documents required. Needed Corrections.
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IDOT Update Eric E. Harm Assistant Chief Engineer IAAP - May 17, 2007
Materials Audit • Office of Auditor General / KPMG • Before 2004 (Laid-back) – MISTIC was good enough • 2004-6 (Under a microscope) – source documents required
Needed Corrections • Accept and assign all materials using proper Method of Acceptance • Training • Provide up-to-date information for materials inspectors
Impacts to Industry • Sampling/testing of materials that have not been tested in some time will now be done. • Rip Rap – Gradation/sizes need to be measured • Plant site sampling and testing may result in questions back to source • Your cooperation and understanding is greatly appreciated
WipFrag • Working on getting approved for use • Full Implementation - Jan. 2008 (?)
RAP Recycled Asphalt Pavement
% Changes in HMA 1/ For HMA Shoulder and Stabilized Sub-Base (HMA) N-30, the amount of RAP shall not exceed 50% of. the mixture 2/ Value of Max % RAP if 3/8 RAP is utilized.
SpG for Natural Aggregate RAP • Northern Districts (1 & 2) = 2.660 • Southern Districts (3 – 9) = 2.630 • Steel Slag RAP will still be tested before use • Talking about Fractionating for more consistency
Field VMA • Currently - VMA is tested in the design phase only • Now – VMA will be tested in production phase
Why do we need Field VMA? • Maintain the correct amount of effective (not absorbed) AC • Prevent over & under asphalting • Better tool for trouble shooting/controlling mixes • Purchase mix that better represents mix design • Improved resistance to stripping • Mix durability – uniformity should lead to longer performance
How Aggregates Can Affect VMA • Angularity • Hardness • Specific Gravity
Friction Trailer • This week - being calibrated at NASA • New aggregate types are tested with trailer before given friction category for HMA use • 7 years since the new friction policy went into affect
ASR Alkali-Silica Reactivity
Spec. Overview • Each Gravel and Natural Sand Source are: • Being tested using ASTM 1260 • Given an ASR Expansion # • Based on ASR Expansion # • Mitigation may be necessary when used • Various Mitigation Options Available • Limestone and Dolomite Sources are given a predetermined ASR Expansion #
Implementation • Currently, on a trial basis, used in Dist. 1 and 4 • Bigger Concrete Jobs • Future - Statewide Implementation
IDOT Not IDOT