CE 3700 Final Exam
Densification property
%Gmm
Cutbacks: -Rapid cure (ex. ______) is a ____ volatility of solvent -Medium cure (ex. ____) is a ____ volatility of solvent -Slow cure (ex. ______) is a ___ volatility of solvent
-RC: gasoline; high -MC: kerosene; moderate -SC: low viscosity oil; low volatility
Dynamic Shear Rheometer -Test is done at several temperatures until it surpasses the minimum of _____ -Identifies _____ and _____ properties and behaviors -Finds binder's _____ ____ modulus and ____ ____ -What results in a stiff binder -When emphasizing rutting resistance, a minimum value is placed on the ____ component of the _____ ____ modulus -When emphasizing fatigue cracking resistance- _____ is desired and _____ has to be limited -Modulus varies between ____ and ____. -Angle varies between _____ and ____ degrees with ____ degrees being complete viscous behavior
1 kPa viscous and elastic complex shear; phase angle high modulus and low angle elastic; complex shear elasticity; stiffness 0.07-0.87 psi 50-90
4 Steps in Mixture Design
1. Materials selection 2. Design agg. structure 3. Design asphalt content 4. Evaluate mixture
Two conditions that low temperature cracking can occur under
1. temperature drops dramatically 2. repeated expansion and contraction due to temp fluctuation
Properties considered in evaluation of aggregates for HMA (6)
1.Internal Angle of Friction 2. Particle Shape 3. Cleanliness 4. Toughness 5. Durability 6. Absorption
Maximum value of flat and elongated particles
10%
For FAA, aggregate is allowed to flow freely into a ____ cm^3 cylinder
100
VMA criteria: minimum value is ___%
13%
Penetration Grading -developed in ____ - 1 penetration=___ mm -Done at room temperature -In LA, regulation penetration # is -Colder climates can use binder with ____ penetration # -3 drawbacks
1918 0.1 mm empirical 40 higher Results strictly empirical; only at one temp; rate of loading depends on tested material
An aggregate is considered 100% crushed if ____ or more faces are crushed
2
Mineral filler passes the No. ____ sieve
200
0 crushed faces (<_%) 1 crushed face (>__%) 2 crushed faces (>_%)
25 25 50
VTM: Air voids tend to be in the range of __-__% in a dense graded mixture
3-5
Determine optimum asphalt binder content that corresponds with a VTM of __%
4
Minimum sand equivalent value is __%
45
Natural sands typically <__ FAA Manufacture sands typically <___ FAA
45 42
Minimum % of FAA to prevent _____
45; rutting
IN the U.S. there are __ million miles of road. ___ million are asphalt/concrete, ___ million are gravel, ___ million are un-surfaced
4; 2.3, 1.3, 0.4
__-__% of HMA weight is due to asphalt. __-__% of HMA volume is due to asphalt
5-8; 15-25
Capillary Viscosity Test: -Absolute viscosity can be found at temp of ____ degrees C -Kinematic viscosity can be found at a temp of _____ degrees C -Units? -1 Drawback -Shows relationship between ___ ____ and ____ ____ -More viscous the asphalt, less _____ will occur -Hotter climates want ____ viscous binder -AC 10 has a viscosity of ____ poises
60 135 poises Only tests at a specific temp shear stress to shear rate rutting high 1000
VFA's range is specified between ____-____%. Minimum value is specified to ensure sufficient amt of asphalt for ______. Maximum value is specified to prevent excessive amt of asphalt cement for mixture ______
65-75% durability stability
Range % of VFA
65-80%
%Gmm(Ninitial) maximum
89%
FAA is based on a No. ___ material and on ____ _____ in loose sample
8; air voids
____ percent of vehicle travel occurs on hard surfaces
95
Minimum percent for 1 fractured face is ____. Minimum percent for 2+ fracture faces is ____.
95%;90%
___ percent of hard surfaced roads are asphalt
96
%Gmm(Nfinal) maximum
98%
AASHTO
American Association of State Highway Transportation Officials
ASTM
American Society of Testing Materials
3 Types of Asphalt
Asphalt cements, cutbacks, and emulsions
Materials Selected are
CA, FA, asphalt cement
Concensus properties of aggregate (4)
CAA FAA Flat, elongated particles Clay content
_______ regulations are increasingly limiting the use of cutback asphalt (fumes)
Environmental
2 types of mixture specific gravity
Gmm and Gmb
Relationship of Gsb to Gse and Gsa
Gsa>Gse>Gsb because volume of water is least in Gsa and most in Gsb
3 types of aggregate specific gravity
Gsb, Gse, Gsa
CAA: Elongated is the ratio of ____ to _____ Flat is the ratio of _____ to ______
Length to width Width to thickness
3 Types of Concrete Mix Design Methods
Marshall (TN), Hveem, Superpave
2 Types of Commercial Asphalt Cement
Natural; petroleum-based
Amount of compaction energy is defined by
Ninitial, Ndesign, Nmaximum
What does each set of letters and numbers mean? PG 64-22
PG-performance grade 64-average 7 day high pavement temperature 22- minimum pavement temperature
Another way to put total asphalt content besides %AC is
Pb
Objectives of mix design is to
Resist permanent deformation, fatigue cracking, low temperature cracking, moisture induced damage, and skid. Consider workability
Purpose of Mixture Design
Selection of an optimum amt of asphalt cement content to satisfy a prescribed volumetric and densification
Superpave stands for
Superior Performing Asphalt Pavement
Source properties of aggregate (3)
Toughness Soundness (durability) Deleterious materials (cleanliness)
Natural commercial asphalt cement can be found in _____ and _____
Trinidad and Venezuela
Volume of fine aggregate formula in terms of M (mass) and G (specific gravity)
V=M/G
VFA is the percentage of ____ filled with asphalt
VMA
Volumetrics Criteria (3)
VTM VMA VFA
VFA
Voids Filled with Asphalt
VMA stands for
Voids in Mineral Aggregate
VTM stands for
Voids in Total Mix
Toughness pertains to an aggregates resistance to ______
abrasion
Pavement performance is influenced by ______
aggregate
Mineral Aggregate for HMA Definition
any hard, inert mineral materials used for mixing in graduated particles or fragments. It includes sand, gravel crushed stone, slag, and rock dust or powder
Gsa
apparent specific gravity when no pores are filled
VMA is the volume available for _____ and _____
asphalt and air
2 bituminous materials
asphalt and tar
Clay on aggregate particles reduces ______ ______
binder adhesion
Synonym for HMA: _____ paving mixtures
bituminous
Gsb is
bulk specific gravity when all aggregates pores are filled
Tar -Produced from ____ of ____ -Hazardous to health -____ resistance
burning of coal fuel
Asphalt Cement: -______ material -Naturally occurring -Produced by ______ _____ -Excellent adhesive -Waterproof? yes? no? -Mainly used in ____ applications
cementitious petroleum distillation yes paving
Superpave performance grading system is based on ____
climate
Suitability of Aggregates for Use in HMA Toughness: Conducted on _____ aggregate Initial weight obtained is on Sieve No. __ Final weight obtained on Sieve No. ___ % Loss equation
coarse 4 16 [(initial wt-final wt)/initial wt]*100
Primary consolidation is under ______ conditions
construction
VTM (Va) _____ when %AC increases because
decreases; because asphalt fills the voids
All volumetrics are to use N_____
design
When collecting Gmb, laboratory samples are typically _____ and field samples are typically _____
dry; wet
Gse
effective specific gravity is of the solid volume and volume of permeable pores not filled with asphalt
Emulsion Asphalt: classified based off of _____ -Anionic -____ charge -Aggregate with + charge (ex. ____) -Cationic - _____ charge - Aggregate with - charge (ex. ______)
emulsifier negative; limestones positive; silica gravel
Secondary consolidation is at _____ __ ______ performance
end of life
ESAL stands for
equivalent single axle load, 18000 lb
Used to estimate the relative proportions of _____ and _____
fine agg. and dust
Particle shape pertains to whether the aggregate is _______ and/or ______
flat &/or elongated
CAA is based on _____ _____
fractured faces
Design agg. structure by selecting an agg. _____
gradation
The more angular the aggregate, the _____ the void content
higher
%VFA _____ when %AC increases because
increases because more asphalt means more voids are going to be filled with asphalt
%Gmm _____ when %AC increases because
increases; because more asphalt allows for mixture to become more dense
Cutback asphalt is ____ at room temperature
liquid
Mineral aggregate for HMA is responsible for ______ _______ capacity of pavements
load supporting
Evaluate mixture by figuring out _____ ______
moisture susceptibility
VMA's minimum value is specified based on the _____ ______ ______ ______ in the mixture to ensure its ______
nominal maximum aggregate size; durability
Design asphalt content by finding the _____ ______ _____ Content
optimum asphalt cement
Gmm eliminates the volume of ______ _____. It considers volumes of _____ and _____ _____. Calculations done with values collected with ____ _____
permeable voids; aggregate and asphalt binder; loose aggregate
Cutbacks: Asphalt cements "cut" with _____ _____
petroleum agents
Bending Beam Rheometer -Sample has to have undergone _____ ____ testing and has been placed in a ____ ____ ___ -Determines ____ and ____ state properties -Measures sample's ability not to succumb to _____ -Useful in finding binder's ____ stiffness due to time -Can find _____ ______ modulus -m-value is the _____ of a master stiffness curve; the _____ the slope, the higher the relaxation property -Minimum value is
pressure aging; cold liquid bath stiffness and relaxed low temp cracking creep stress relaxation slope 0.3; higher
Asphalt cements are generally ____ produced material
refinery
Pressure Aging Vessel -Sample must undergo ____ ____ ____ ____ test -Simulates ____ term aging -tests how much the sample ____ -More ______ then more _____ asphalt gets -to prevent cracking, minimum amount of _____ needs to occur
rolling thin film oven long (8-10 years) oxidizes oxidation; viscous oxidation
Internal angle of friction pertains to whether or not the aggregate is _____ or ______
round or cubical
Clay content is based on _____ ______ value
sand equivalent
At room temperature, asphalt cement is _____ and _____ at high temperatures
semi-solid; liquid
Rolling Thin Film Test -Simulates ____ term aging -At a temp of ____ degrees -Due to ______ to _____ and ____ of ____, volatile components of the asphalt cement are lost -Typically mass loss is between ___-____% -If mass lass is greater than ___% then particular asphalt fails -Higher the mass loss, the more ____ the binder becomes
short 163 exposure to heat and jets of air 0.05-0.5% 1% viscous
Rotational Viscometer -Measures the ______ needed to keep spindle rotating at ____ rpm -Conducted at ____ degrees C -Tests whether or not asphalt can be ____ _____ _____ -Maximum value of ___ -Measures _____ of cement, which directly corresponds to the dynamic viscosity
torque; 20 130 ran through pipes 3 Pa*s stiffness
Emulsions: Mixture of asphalt cement, ______, and _____ ______
water and emulsifying agents