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Sampling Asphalt Emulsions. June 2014. TDOT Requires Emulsion samples. Requirements listed in TDOT’s Standard Operating procedures state that samples of emulsions should be taken from asphalt emulsion terminals and from TDOT projects using emulsion to verify the quality of these materials.
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Sampling Asphalt Emulsions June 2014
TDOT Requires Emulsion samples • Requirements listed in TDOT’s Standard Operating procedures state that samples of emulsions should be taken from asphalt emulsion terminals and from TDOT projects using emulsion to verify the quality of these materials.
SOP 1-1 • Emulsions for prime coats, tack coats, and sealers (aka fog seals) – Sampled by the project inspector and once per week thereafter. • Emulsions from Surface Treatments (aka chip seals), Microsurfacing, Slurry sealing and related similar processes- Sampled by the project inspector and once per week thereafter.
SOP 1-1 • Basically, if there’s emulsion on the project, a sample needs to be taken from the field once per week.
Bad EMULSION samples • Often, samples of emulsion are taken that are improperly collected, which can cause them to be contaminated and useless for testing.
Common sampling errors • Samples taken from distributor spray bars can easily become contaminated.
Common sampling errors • Emulsion samples cannot be taken in containers that have been previously used or in metal containers.
Common Sampling Errors • The sooner samples can be tested the better. Emulsion samples can go bad if too much time has passed since sampling or if they have been exposed to extreme heat or cold.
PROPER SAMPLING • The best place to sample emulsions in the field is from the sample valve.
PROPER SAMPLING • Samples should be PROPERLY LABELED and accompanied by a T-2 (DT-0044) sample form. Identify: • The material (SS-1, CRS-2p, etc), • Contract Number, • Date sampled, • Sampler, • Where the sample was taken from (distributor, contractor’s storage tank, etc) • For materials where dilution is permitted (shoulder fog seals or tack coat from microsurface projects) note whether the sample was taken before or after dilution. • Dilution is not permitted for tack coats on HMA projects.
PROPER SAMPLING • All samples should be taken by contractor personnel, observed by TDOT employee, either from the contractor’s storage tank or directly from the distributor. • All samples should be taken from the sample valve, and a MINIMUM of 1-gallon of material should be run through the sample valve and wasted prior to collecting the sample. • All emulsion samples should be collected in wide-mouth jars or bottles made of plastic or wide-mouth plastic-lined cans with lined screw caps.
PROPER SAMPLING Sample containers can be received from Regional or HQ M&T
PROPER SAMPLING • Containers should be completely filled to eliminate possible crusting or condensation in the container. • When filling containers, avoid filling too quickly to avoid entraining air in the sample. • Samples shall be not exposed to direct sunlight for long periods of time and not allowed to freeze. • Per TDOT M&T SOP 1-1, samples should be received at the TDOT central laboratory in Nashville as soon as reasonably possible. Samples taken more than two weeks after sampling are considered expired and will be discarded.
