IDOT UpdateEric E. Harm

Assistant Chief EngineerIAAP - 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 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

WipFrag Working on getting approved for use Full Implementation - Jan. 2008 (?)

RAP

Recycled Asphalt Pavement

% Changes in HMAHMA MIXTURES 1/ MAXIMUM % RAP

Ndesign Binder/Leveling Binder

Surface Polymer Modified

30 30 30 10

50 25 15 10

70 15 / 25 2/ 10 / 15 2/ 10

90 10 10 10

105 10 10 10

1/ For HMA Shoulder and Stabilized Sub-Base (HMA) N-30, the amount of RAP shall not exceed 50% of. the mixture2/ 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

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?

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

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

Not IDOT

IDOT

Thank You