2018 SCDOT Asphalt Specification Changes
SCDOT 2018 Asphalt Specification Changes
Just in this past year there have been a lot of changes to several of the SC Department of Transportation's asphalt specifications. Below is a rundown of the changes, with hyperlinks to each specification.
SC-T-97 - Method for Verification of Contractor Asphalt Acceptance Test Results (link)
This past month, SCDOT approved and published the latest version of SC T-97, which was modified in conjunction to the changes to SC-M-400.
SC-M-400 - Asphalt Mixture Quality Acceptance (link)
Major changes to SC-M-400 include but are not limited to:
- Transition from Percent Within Limits (PWL) to closing a day’s production out daily with the use of Absolute Average Deviation (AAD).
- Using gradation in lieu of Volumetrics (Air Voids and VMA) for Lot Pay Factor (LPF).
- Volumetrics will be required on the first LOT of a contract for each Job Mix Formula (JMF) & after any mix-test failure.
- Intermediate C – accepted using gauge shots in lieu of cores.
- Mixes that require gauge for in-place density acceptance: one gauge reading per 500-foot section-sublot (formerly 10/LOT).
- All mixes that require cores (Surface Type A-B and Intermediate Type A, B & B-Special) will be taken on a 1 core per 1500-foot section-sublot basis.
- In-place density for cores will be based on average density - not PWL
- Increasing average in-place density to 93.0 - 93.9 to obtain a LPF of 100%
- LPF are no longer weighed if a contractor obtains 105% for Binder Content, 100% for Gradation, and 95% for In Place Density...The LPF is the lowest value...95%.
Contact Cliff Selkinghaus (SelkinghCB@scdot.org) at the SCDOT Office of Materials and Research for a copy of the latest version of the 2018 QA Workbook.
SC-M-402 - Material Properties for Asphalt Mixtures (link)
- Added Intermediate B Special and
- Allowing either hydrated lime or LASA in mixtures containing PG 64-22.
Supplemental Specification: Removal of Existing Asphalt Pavement before Patching
- Allowing other mix types to be used in FDP based on depth of patches. (link)
- Tables of options for FDP and update to the specification. (link)
SC-M-406 – Liquid Anti-Strip Additives (LASA) for Asphalt Mixtures (link)
The major changes involve:
- Asphalt terminals adding the LASA product to the tanker load during pump out operations
- Allowing LASA in other mix types with PG 64-22.
SCDOT Mix Design Guidelines for Lime to LASA Changes
1% Lime to 0.7% LASA
- Submit a SCDOT 269 form - Same As to LASA, enter the 1% into a dry screening in lieu of hydrated lime to get 100% aggregate blend
- Make 4 ITS/TSR pills and provide results
- Make 2-3 Gyratory pills at optimum binder content and check volumetric properties against original design targets (if not comfortable with target values, then redesign)
LASA to LASA (change brands-products not listed on job mix)
- Make 4 ITS/TSR pills and provide results, will show all brands and results on a single JMF
For any additional questions regarding the new changes, please contact Cliff Selkinghaus at the SCDOT Office of Materials and Research.