Plant Materials Control

145 Pages·2014·33.62 MB·English

Laboratory for the Certification
of Asphalt Technicians
LabCAT Program
B - Plant Materials Control
2015 Presentation Manual
In cooperation with the Colorado Asphalt Pavement Association,
the Colorado Department of Transportation, and the
Federal Highway Administration

7/30/2014
SSttaannddaarrdd MMeetthhoodd ooff TTeesstt
for Reducing Field Samples
of Aggregate to Testing Size
CDOT CP - 32
AASHTO T –248
Purpose of Splitting
(cid:121) These methods provide for reducing large
samples of aggregate to measure
characteristics in a manner that the smaller
test portion is most likely to be a
reppresentation of the largger sampple,, and thus
of the total supply
1
7/30/2014
(cid:121)(cid:121) AAggggrreeggaatteess mmuusstt bbee ssaammpplleedd iinn aaccccoorrddaannccee
with CP-30.
(cid:121) Samples must be split properly to obtain
representative test specimens
Methods
(cid:121) Method A - riffle type splitter
(cid:121) Method B - quartering
(cid:121) Method C –
◦ selection by scoop (CDOT)
◦ miniature stockpile method (AASHTO)
2
7/30/2014
Riffle Apparatus
(cid:121) Riffle type splitter with
variable size openings
(cid:121) Hopper to retain sample
or Flat scoop (feeder
pan) equal in length to
the overall assembly of
chutes
(cid:121) Collection pans,
minimum of two (2),
equal in length to the
overallll assembblly off
chutes
(cid:121) Splitter brush to clean
chutes of adhering fines
Quartering Apparatus
(cid:121)(cid:121) 66’ xx 88’
quartering
canvas or
(cid:121) Clean, hard,
level surface
((AASHTO))
(cid:121) Flat, square
end shovel
3
7/30/2014
Scoop & Miniature Stockpile
Apparatus (Fine Aggregate
Only)
(cid:121) Large flat bottomed
mixing pan (CDOT) or
a clean, hard, level
surface
(cid:121) SSmmaallll, ffllaatt, ssqquuaarree
end scoop
By Riffle Splitter
(cid:121) Riffle splitting is always preferable to hand
qquuaarrtteerriinngg.
(cid:121) Proper size openings required.
(cid:121) Opening shall permit easy passage of the largest
pparticles in the sampple.
(cid:121) For variable splitters the openings should be 1.5
times the size of the largest particles
4
7/30/2014
Method A - Riffle Splitter
(cid:121) An even number of equal width chutes, but not less
tthhan 88 ffor coarse, or 1122 ffor ffiine aggregattes
(cid:121) The splitter shall be equipped with a hopper or
straight-edged pan which has a width equal or slightly
less the overall width of the assembly of chutes
(cid:121) Sample at SSD or drier
(cid:121) Two pprocedures to spplit sampple
(cid:123)Hopper
(cid:123)Scoop (feeder pan)
Riffle Splitter-Control
Flow Hopper
(CDOT)
(cid:121) Sample poured into the closed
hopper from the sample
container
(cid:121) Use all material
(cid:121) Uniformly distribute from edge
to edge
(cid:121) Open release handle and
allow the sample to flow freely
tthhrroouugghh tthhee cchhuutteess
(cid:121) The first split that is then
reintroduced to the splitter
assists in mixing the sample
5
7/30/2014
Riffle Splitter-Control Flow
Hopper
(CDOT)
(cid:124) Then remove both pans from the splitter
(cid:124) Save material in one ppan for other tests
(cid:124) Pour half of the remaining pan into the
hopper
(cid:124) Reverse endsof pan
(cid:124) Pour the remaining sample into the hopper
(cid:124) Uniformly distribute material in hopper
(cid:124) Open release handle and allow the sample
to flow freely through the chutes
(cid:124)(cid:124) uussee aalltteerrnnaattee ppaannss ffoorr ffuurrtthheerr rreedduuccttiioonn
(cid:124) Splitting is continued until the sample is
reduced to the required specimen size
Riffle Splitter
(AASHTO)
(cid:121) Splitting
continued from
one side until
sample reduced
to required
specimen size
6
7/30/2014
Riffle Splitter without
control hopper
(CDOT)
(cid:121) Place entire sampple in a
large mixing pan and mix
thoroughly
(cid:121) Scoop the material from the
pan with the feeder pan
(cid:121) Uniformly distribute in
ffeeeeddeerr ppaann
(cid:121) First, slowly pour half the
sample from one side
Riffle Splitter without
control flow hopper
(CDOT)
(cid:121) Pour the other half from
the other side
(cid:121) Continue until entire
sample has been
passed through the
chutes
(cid:121) Use alternate ppans for
further reduction to
desired specimen size
7
7/30/2014
Method B -Quartering
(cid:121) Sample
ddeeppoossiitteedd oonn
clean, hard, level
surface or canvas
(6’ X 8’ canvas)
(cid:121) Mix material
thoroughly by
ttuurrnniinngg tthhee eennttiirree
sample over onto
itself 3 times
Method B -Quartering
(cid:121) Material shoveled into cone
(cid:121) Cone flattened at appex into in circular layyer
(cid:121) Diameter equals approx. 4-8 times the thickness
8