Equipment needed for HMA Facilities, trucks, placement equip, compaction equip
Agg in Asphalt Cement blend of 2-4 stockpiles of materials
2 types of HMA facilities Batch Mix, Drum Mix
2 types of Drum mix facilities Parallel Flow, counter flow
parallel flow agg moves in same direction (parallel) to exhaust
counter flow agg flows against the exhaust gases
most common counter flow facility double barrel
whats more common batch mix or drum mix drum mix
(T/F) The first 2 or 3 components of drum & batch mix are True
virtually the same
Primary difference btw batch vs drum mix the drying operation
Pugmill twin shaft counter rotating mixer
"RAP" Recycled Asphalt Pavement
Stripped old road, removed by a milling machine, added back into a new mix.
Drum Dwell time 3-4 mins
As the Drum diameter increases..... the production rate increases
Flights? control movement of the Agg. inside drum
2 types of burners Forced air, Draft
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Largest factor affecting the production rate of certain size Stockpile Moisture Content
drum
% of roads asphalt paved 96
Does asphalt need rebar no
_____ tons of asphalt made anually 1/2 Billion
History of Asphalt first used in 1870's
asphalt lakes of Trinidad
petroleum asphalt took off
Asphalt soluble in petroleum, by product of petroleum distilation
Tar not soluble in petroleum, coke by product
Asphalt Binder called: bitumen or asphalt cement
black sticky stuff that glues everything together
Cutback Asphalt Binder cut with solvent
Emulsion Mixture of Binder, water and emulsifying agent
Superpave 1990s SHRP contract, describes the mix design of asphalt concrete
Mastic Asphalt Binder and sand portion
Penetration Testing flaw gaps in the grading scale
done at room temperature,
leaves out temp susceptibility of binder
Penetration testing Designation ASTM-D946
Viscosity Testing AC-AR Grading
AC Grading Represents Virgin Asphalt, Widespread use
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