HMA in Quebec Flashcards
5 quebec realities
- temperature from -30 to 30
- high daily delta T during thaw period
- overlay : more than 85% of paving projects
- low temperature cracking is general
- reflective cracking in overlay projects
name 2 types of rutting
- rutting by excessive creep in the HMA
2. rutting by deformation of granular layers
what does low temperature cracking to the road?
cracks perpendicular to the road (road shrinks longitudinally and therefore road cracks perpendicularly)
what is fatigue cracking
when there are multiple cracks in every direction
what is the freeze-thaw action
frost heaving pulls the road up from the middle. water pumping feeding the ice lenses under the road.
what happened in 1991?
studies of the french method by the laboratoire des chaussées
what happened in 1993?
studies of the superpave method (first hot mix LC)
what happened in 1997?
standardization of the laboratoire des chaussées method
what happened in 2008?
standard 4202 used (4201 archived)
what is the volumetric approach
fixed volume of asphalt for each mixture
3 levels for basic concepts
level 1 : workability
level 2 : rutting testing
level 3 : complex modulus, fatigue, thermal properties (in development)
describe level 1
gyratory compactor.
600 kPa pressure
150 mm diameter
30 gyrations/minute
1,25° inclination
describe level 2
rutting test.
- not more than 10 mm rut depth
- 1k, 3k and 30k cycles
- 5 kN load applied
- 600 kPa tire pressure
- 50, 58 and 60 °C
what is ESAL
equivalent single axle load
what is aadt
average annual daily trafic
3 necessary info for the LC mix design method
- traffic info (type, esal, aadt, other)
- environmental constraints
- construction issues – pavement function
4 things HMA should satisfy according to the LC mix design method
- minimum asphalt cement content (durability, ravelling, stripping, thermal cracking, resistance to fatigue and rutting)
- stability under traffic loadings (rutting and creep)
- minimum voids (to avoid binder bleeding)
- maniability and good compaction ability
binder selection is based on
Range of T°
level of traffic
4 components of the global approach of the LC method
- binder selection
- optimisation of the components
- verify rutting resistance
- verify moisture damage resistance
quebec climate zones : define
3 climate zones
zone 1 : montréal métropolitain
zone 2 : côtes + sud du québec
zone 3 : nord du québec
what is coarse graded
enrobés grenus : EG
what is dense graded
enrobés semi-grenis : ESG
what is correction course
enrobé de correction : EC
what is stone matrix
enrobés de matrice à pierre : SMA
what is base course
enrobé pour couche de base : GB
what is SGC
superpave gyratory compactor
ESG-10 is
the type of surface course most used, it performs well on all types of roads
EG-10 is
used on highways, near urban zones (diminishes road-tire noise)
EGA-10 is
EG-10 with 1,3% asbestos fibers and a stronger grade of asphalt
what is EGM-10 for?
for thin overlays (M= mince)
GB-20 v ESG-14
GB-20 remains the best chioce for base course.
ESG-14 is a possibility in cold weather but its bearing and rutting resistance is less
ESG-14
performs well as a single course but it is difficult to formulate
layer thicknesses
top layer : 30 to 60 mm
middle layer : 100 to 150 mm
base layer : 75 to 100 mm
granular or stabilized foundation
what is the maximum percentage of recycled pavement allowed in new pavement in quebec since 2008?
20%
can asphalt shingles and warm mix asphalt be used in the MTQ road network?
yes but with a performance follow-up
