CVEN 342 Exam 1

The mechanism of material failure caused by repeated loading

fatigue

Asphalt concrete is an example of the following type of composite material

large particle reinforced

A desirable aggregate characteristic for quality Asphalt Concrete is

dense gradation

If MC is less than AC, the aggregate is

dry in the stockpile

The Fordyce Company that produces aggregates for Asphalt Concrete and PCC uses

transportation by barge

Specific Gravity values used in AC volumetric calculations include

Gse, Gb(od), Gmm

The critical agin state for asphalt binder characterization to determine resistance to fatigue cracking is

After Rolling Thin Film Oven Test (RTFOT) and Pressure Aging Vessel (PAV)

A common component of Asphalt Concrete in the 2000s for all types of mixtures is

Reclaimed Asphalt Pavement

When utilizing the concept of time temperature superposition to form a master curve: data measured at _____ temperatures is shifted to _____ times of loading

warmer, longer

The superpave volumetric mix design system for AC addresses these shortcomings of traditional mix design:

measurement of compatibility, inclusion of large aggregates, selection of both unmodified and modified binderes based on climate

Rutting resistance of Asphalt Concrete is enhanced by:

aging

The PG binder specification addresses the following shortcomings of traditional systems:

characterization at low pavement temperatures, inclusion of long term agin, measurement of fundamental properties tied to primary distresses

In the PG binder specification, a minimum stiffness parameter is used to control the binder's contribution to

resistance to rutting

Liquid asphalts as compared to traditional asphalt cement binders include ______ ______, and an ______ agent.

asphalt cement, emulsifying

Important aggregate characteristics for AC

dense gradation, rough surface texture, angular shape

Lab tests for aggregate characterization

LA abrasion, Dynamic Shear Rheometer, soundness

Examples of material behavior:

maxwell, burgers, two springs in series

Steps in Aggregate production

washing, crushing alluvial deposits, washing

AC production and placement:

drum mix plants produce mix continuously, aggregate gradation is better controlled in batch plants, emissions control required at hot mix plants

mechanisms of material failure

creep, fracture, fatigue

specific distress in asphalt concrete

rutting, thermal cracking, fatigue cracking

low binder contents provide the following benefits to asphalt concrete mixture:

stability

Lab tests:

RV, DSR, BBR

an important aggregate characteristic for use in quality asphalt concrete is

angular shape

if MC is greater than AC, the aggregate is

wet in the stockpile

the mechanism of material failure caused by repeated loads is

fatigue

ways to determine composition of aggregates as composite of minerals

x-ray analysis, composition CoTE

adding cumulative % retained values for specific sieves and divide by 100

fineness modulus

leads to inconsistent feeds into the hot plant/batch plants

stockpile segragation

formation of expansive gels - produces internal stresses which may cause cracking

alkali silica reactivity (ASR)

max specification

you want it

min specification

you don't want it

Asphalt binders are produced by

fractional distillation of petroleum

The most recycled product in the US used in civil engineering construction materials is

reclaimed asphalt pavement (RAP)

A maxwell model of rheological response:

will sustain permanent deformation on unloading

a failure curve due to sustained loading mirrors that of the following AC mixture test:

thermal stress restrained specimen test (TSRST)

the composite behavior of AC depends on the

aggregate structure

the type of aggregate gradation that provides the best AC performance for balanced performance in terms of the three primary forms of distress is

dense

aggregate gradation is defined and plotted for each sieve size as

cumulative percent passing by weight

the aggregate specific gravity used in AC mix design

Gb(OD)

a durability test to evaluate aggregates used in AC at the fordyce company plants include:

transporting by barge

the critical aging state for asphalt binder characterization to determine resistance to rutting is

after rolling thin oven test (RTFOT) only

in the PG binder specification, a maximum stiffness parameter is used to control the binder's contribution to

resistance to cracking

the PG binder specification addresses the following shortcoming of traditional binder grading systems:

characterization at low pavement temperatures

the concept of time-temperature superposition is used characterize AC in terms of a master curve for the following parameter

stiffness

durability of asphalt concrete can be evaluated using:

the tensile strength ratio (TSR)

cracking resistance of AC is enhanced by

high binder contents

the Superpave volumetric mix design system for AC includes the following steps shown in the correct order:

material selection, selection of aggregate gradation, selection of optimum binder content, evaluation of moisture susceptibility

pavement design plays a critical role in AC resistance to

moisture susceptibility

the superpave volumetric mix design system for AC is based on

selection of both aggregate gradation and optimum binder content from volumetric properties at 4% AV and compaction characteristics

durability parameter, max amount of aggregate that can break down

LA abrasion

why do we use oven dry bulk SG with aggregates?

we know aggregates have to be dried out to get a good bond

binder selection is based on

climate