Download Asphalt Concrete: Questions and Answers for Civil Engineering and more Exams Nursing in PDF only on Docsity!
asphalt-concrete Questions with
Verified Answers
A mechanical device on an asphalt batch plant, consisting of paddles attached to rotating shafts, for mixing aggregates and asphalt cement. Select one: a. Hot oil heater b. Pug mill c. Weigh hopper d. Intake Hopper - ANSWERSpug mill The top or riding surface of a pavement structure. Select one: a. Surface course b. Lift (mat) c. Leveling course d. Binder Course - ANSWERSsurface course The process of shaping the concrete surface to correct elevation by striking off the excess concrete. Select one: a. Contraction Joints b. Penetration Test (AASHTO) c. Screeding d. Breakdown - ANSWERSscreeding Are a blend of asphalt cement and a fuel product. Select one: a. Hot-mix Asphalt b. Windrow c. Asphalt Cutbacks d. Flexible Pavement - ANSWERSasphalt cutbacks Where the paving machine rides on steel forms that are set to the proper line and grade for the finished slab. Select one: a. Nipped b. Breakdown c. Formed d. Frequency - ANSWERSformed
In concrete, the chemical reaction between cement and water. The features of this reaction are a change in matter, in energy level, and in rate of reaction. Select one: a. Hydration b. Expansion Joints c. Dwell Time d. Hveem - ANSWERShydration By remixing the asphalt concrete, reduced thermal segregation creates uniform stiffness that allows for rougher pavement construction. Select one: True False - ANSWERSfalse. By remixing the asphalt concrete, reduced thermal segregation creates uniform stiffness that allows for SMOOTHER pavement construction Smaller commercial aggregate plants are the major source of crushed stone for the construction industry in metropolitan areas. Select one: True False - ANSWERSfalse. LARGER commercial aggregate plants are the major source of crushed stone for the construction industry in the metropolitan areas. Properly vibrated concrete is a lower-quality concrete, in terms of strength, reinforcement protection, resistance to aggressive agents, and overall appearance. Select one: True False - ANSWERSfalse. higher quality Increasing roller speed increases compactive effort. Select one: True False - ANSWERSfalse. Increasing roller speed REDUCES compactive effort. The pavement performance would not suffer if asphalt concrete is made from a segregated stockpile. Select one:
The transverse inclination of a road way or other surface. Select one: a. Cross-slope b. Hveem c. Dwell Time d. Contraction Joints - ANSWERScross slope A high-tech group of machines capable of uniformly blending, heating, and mixing the aggregates and asphalt cement to produce asphalt concrete, while meeting strict environmental regulations. Select one: a. Windrow elevator b. Grade or string line c. Intake Hopper d. Asphalt Plant - ANSWERSasphalt plant One size larger than the first sieve that retains more than 10% of the aggregate mass. Select one: a. Nominal maximum aggregate size (NMAS) b. Asphalt Emulsions c. Nipped d. Cross-slope - ANSWERSnominal maximum aggregate size (NMAS) A method of asphalt mix design based on the cohesion and friction of a compacted specimen. Select one: a. Expansion Joints b. Cross-slope c. Screeding d. Hveem - ANSWERShveem The sweeper/broom is used to ensure proper bonding between the new asphalt and the old pavement. Select one: True False - ANSWERStrue If the mix is too cold, the mat will tear and become scarred. Select one: True False - ANSWERSfalse HOT
The recommended range to ensure consolidation during concrete pavements is 7, to 11,000 vibrations/min. Select one: True False - ANSWERStrue Slipform paving is a speedy and economical method for producing smooth and durable concrete pavement. Select one: True False - ANSWERStrue To produce concrete of high quality, aggregates should be clean, hard, strong, durable, and have a bulky shape. Select one: True False - ANSWERStrue A batch plant mixes 24 tons of asphalt mix with an average mixing cycle of 1.5 min. Plant efficiency is 85%. Estimate plant production in ton/hr. Select one: a. 816 tph b. 650 tph c. 212 tph d. 300 tph - ANSWERS816 tph 60/1.5= 4024= 960.85= A specification requires a residual application rate of 0.035 gal/sy. The distributor spray bar coverage is 6 ft. Estimate the gallons of emulsion needed for a 12 ft wide 5,280-ft stretch of paving. Select one: a. 533 gallons b. 894 gallons c. 745 gallons d. 246 gallons - ANSWERS246 gallons 12* .035/
d. Wet collector - ANSWERSflights Blend concrete by rapid rotary motion of paddles inside the mixing drum. Select one: a. Apron feeder b. Intake Hopper c. Power Mixer d. Screed - ANSWERSpower mixer The asphalt mixture must seal the base, subbase, and subgrade to prevent water intrusion. Select one: True False - ANSWERStrue If asphalt is delivered at a cooler temperature, the system must be capable of raising the temperature of the delivered asphalt cement. Select one: True False - ANSWERStrue If the volume decreases, the screed moves up, resulting in increased mat thickness. Select one: True False - ANSWERSfalse. If the volume decreases, the screed moves DOWN, resulting in REDUCED mat thickness. Ideally, an aggregate gradation should be provided that requires the maximum amount of expensive asphalt cement. Select one: True False - ANSWERSfalse. minimum Crushing plants use step reduction because the amount of size reduction accomplished is indirectly related to the energy applied. - ANSWERSfalse. Crushing plants use step reduction because the amount of size reduction accomplished is DIRECTLY related to the energy applied. Eliminates fines from the material entering the crusher and requires less maintenance
Select one: a. Hot bins b. Vibrating Feeder c. Grizzly d. Power Mixer - ANSWERSvibrating feeder Are a mineral admixture that replaces a percentage of Portland cement in the mix. Pozzolans enhance the concrete properties and improve mix economics. Select one: a. Asphaltic Concrete b. Rubberized asphalt c. Windrow d. Pozzolans - ANSWERSpozzolans The specification relates engineering measures of asphalt cement properties to specific pavement performance matters. Select one: a. Porosity b. Dwell Time c. Performance Grades of Asphalt Cements d. Hydration - ANSWERSperformance grades of asphalt cements A new layer of asphalt mix placed over a distressed roadway or unbound base to improve its profile prior to resurfacing. Select one: a. Prime coat b. Seal Coat c. Leveling course d. Binder Course - ANSWERSleveling course A layer of asphalt mix separately placed and compacted. Select one: a. Binder Course b. Surface course c. Lift (mat) d. Leveling course - ANSWERSlift (mat) A layer of asphalt mix placed between the base and the surface courses in the pavement structure. Select one: a. Binder Course b. Lift (mat) c. Tack coat d. Leveling course - ANSWERSbinder course
An acronym for Superior Performing Asphalt Pavements. An asphalt concrete mix- design method for determining the aggregate structure and proportions of aggregate and asphalt cement based upon desired performance. Select one: a. Contraction Joints b. Hydration c. Penetration Test (AASHTO) d. SuperPave - ANSWERSsuperpave The ability of a set of rollers to draw a particle into the space between them by friction. Select one: a. SuperPave b. Baghouse c. Nipped d. Amplitude - ANSWERSnipped A feeder constructed of overlapping pans that form a continuous belt. Select one: a. Apron feeder b. Pug mill c. Hot elevator d. Vibrating Feeder - ANSWERSapron feeder Blends concrete by lifting the ingredients with the aid of fixed blades inside a rotating drum and then dropping the material by overcoming the friction between the mixture and the blades. Select one: a. Hot oil heater b. Flights c. Apron feeder d. Freefall Mixer - ANSWERSfreefall mixture An application of liquid asphalt over an untreated base to coat and bond the loose aggregate particles, waterproof the surface, and promote adhesion between the base and the overlying course. Select one: a. Leveling course b. Surface course c. Prime coat d. Lift (mat) - ANSWERSprime coat Longitudinal tinning has the advantage of directly channeling the water toward the pavement edge. Select one:
True False - ANSWERSfalse transverse By holding several loads of asphalt concrete, the material transfer device increases surge loading of the paver. Select one: True False - ANSWERSfalse reduces The screen unit ejects oversized material out of the production cycle. Select one: True False - ANSWERStrue Cone crushers are used as primary crushers. Select one: True False - ANSWERSfalse Cone crushers are used as SECONDARY or TERTIARY crushers. Drum and batch plants are the two most common plant types. Select one: True False - ANSWERStrue A system that overrides the self-leveling action of the asphalt paver screed and enables paving to a predetermined grade and slope, using either a rigid or a mobile type reference. Select one: a. Revibration b. Automatic Screed Controls c. Penetration Test (AASHTO) d. Screeding - ANSWERSautomatic screed controls The part of the pump that receives and holds concrete before it is sucked into the pumping cylinder. Select one: a. Intake Hopper b. Apron feeder c. Asphalt Plant
False - ANSWERSfalse. increased Asphalt cements serve the very important functions of bonding the aggregate particles together, preventing the entrance of moisture, and acting as a cushioning medium. Select one: True False - ANSWERStrue Asphalt pavements are designed to be compacted at a specified density. Select one: True False - ANSWERStrue Fresh concrete have minimal variability throughout, both within a given batch and between batches. Select one: True False - ANSWERStrue A wire or string erected at a specified grade and alignment that is used as a reference for an automatic control system on a paver, a milling machine, or a fine-grade machine (trimmer). Select one: a. Flights b. Grizzly c. Grade or string line d. Pug mill - ANSWERSgrade or string line The top surface layer of an asphalt pavement, usually less than 1 in. thick, to improve skid resistance and smoothness. Select one: a. Surface course b. Lift (mat) c. Friction course d. Leveling course - ANSWERSfriction course A batch plant component, usually located under the hot bins, in which the aggregates and asphalt cement are weighed prior to discharge into the mixing pugmill. Select one: a. Leveling Arms b. Weigh hopper
c. Gyratory crushers d. Belt feeder - ANSWERSweigh hopper Are produced by using a colloidal mill to break down asphalt cement into very fine "globules" that are introduced into water that has been treated with an emulsifying agent. Select one: a. Formed b. Asphalt Emulsions c. Job Mix Formula (JMF) d. American Concrete Institute (ACI) - ANSWERSasphalt emulsions Consists of number of widely spaced parallel bars, can be used to scalp materials ahead of the primary crush. Select one: a. Windrow elevator b. Power Mixer c. Grizzly d. Grade or string line - ANSWERSgrizzly Joints for the purpose of regulating cracking from the unavoidable and unpredictable contraction of concrete. Select one: a. Hveem b. Penetration Test (AASHTO) c. Contraction Joints d. Asphalt Emulsions - ANSWERScontraction joints A specially designed distributer truck is utilized when applying an asphalt prime, tack, or seal coat. Select one: True False - ANSWERStrue The porosity of an aggregate affects the amount of asphalt cement required in a mix. Select one: True False - ANSWERStrue Different mix-design procedures will require similar quality-control parameters for construction. Select one:
A type of rake used to smooth out minor surface irregularities in the hot asphalt mix behind the paver. It has a straight-edge side and a toothed side. Select one: a. Apron feeder b. Gyratory crushers c. Hot elevator d. Lute - ANSWERSlute A linear pile of material placed on a grade or previously placed mat for later pickup and spreading. Select one: a. Stone matrix asphalt (SMA) b. Windrow c. Binder d. Hot-mix Asphalt - ANSWERSwindrow Grooves applied to the concrete surface to channelize surface water. Select one: a. Tining b. Performance Grades of Asphalt Cements c. Hydration d. Dwell Time - ANSWERStining Admixtures are added to the concrete mixture to improve workability, to impart color, to retard the initial set of concrete, to gain rapid hardening and high initial strength, to improve flowability, and to waterproof the concrete. Select one: True False - ANSWERStrue Type IV is a special cement with low heat of hydration. Its strength develops at a slower rate. Select one: True False - ANSWERStrue Slipforming requires low slump mixes so that the pavement maintains shape after placing; a maximum slump of 1" to 2" is commonly specified. Select one: True False - ANSWERStrue
The surge silos enable the batch plant to operate dependent of immediate truck availability. Select one: True False - ANSWERSfalse. Independent Jaw crushers are usually designed with the toggle as the strongest part. Select one: True False - ANSWERSfalse, weakest A feeder that is used for smaller sizes of material, usually sand or small-diameter aggregates. Select one: a. Pug mill b. Wet collector c. Weigh hopper d. Belt feeder - ANSWERSbelt feeder The magnitude of the motion in each vibration. Select one: a. Revibration b. Dwell Time c. Amplitude d. Penetration Test (AASHTO) - ANSWERSamplitude An asphalt mix containing powdered or shredded rubber that is introduced into the mix to produce a more resilient pavement. Select one: a. Binder b. Asphaltic Concrete c. Flexible Pavement d. Rubberized asphalt - ANSWERSrubberized asphalt The asphalt cement material in a paving mix used to bind the aggregate particles together, to prevent the entrance of moisture, and to act as a cushioning agent. Select one: a. Windrow b. Stone matrix asphalt (SMA) c. Asphaltic Concrete d. Binder - ANSWERSbinder
The contact area of a steel wheel roller will increase as the rolling progresses, thereby decreasing the contact pressure. Select one: True False - ANSWERSfalse the contact area of a steel wheel roller will DECREASE as the rolling progresses, thereby INCREASING the contact pressure. The process whereby the concrete is vibrated again after it has been allowed to remain undisturbed for some time. Select one: a. Revibration b. Batch c. Dwell Time d. Performance Grades of Asphalt Cements - ANSWERSrevibration A heater for increasing the temperature of heat transfer oil. The heated transfer oil maintains the temperature of stored liquid asphalt, or mixed asphalt concrete that has been placed in storage silos. Select one: a. Pug mill b. Lute c. Hot oil heater d. Apron feeder - ANSWERShot oil heater A rut-resistant mixture that relies on stone-on-stone contact, coupled with fiber or polymer-modified asphalt cement, to provide high-strength, load-carrying capability. Select one: a. Binder b. Stone matrix asphalt (SMA) c. Windrow d. Flexible Pavement - ANSWERSstone matrix asphalt A composite material that is prepared in a hot-mix plant and used for construction of highway, parking lot, or airfield pavements capable of supporting high traffic load volumes and axle loads. Select one: a. Asphaltic Concrete b. Stone matrix asphalt (SMA) c. Binder d. Flexible Pavement - ANSWERSasphaltic concrete
A light application of liquid asphalt, usually emulsified with water, placed between pavement courses during construction. It is used to help ensure a bond between the surface and the new mat that is being placed. Select one: a. Surface course b. Lift (mat) c. Leveling course d. Tack coat - ANSWERStack coat An international organization providing education, certification, and information about concrete. Select one: a. Dwell Time b. American Concrete Institute (ACI) c. Performance Grades of Asphalt Cements d. Contraction Joints - ANSWERSamerican concrete institute Higher ambient air temperatures allow more time for compaction. Select one: True False - ANSWERStrue When fine aggregate is added to Portland cement mixture, concrete is produced. Select one: True False - ANSWERSfalse. When fine aggregate (aggregate whose size range lies between the No. 200 mesh sieve and the No. 4 sieve) is added to the Portland cement, the resulting mixture is termed mortar. Then, when coarse aggregate is included (aggregate sizes larger than the No. 4 sieve but less than 3 in.) CONCRETE is produced. Truck production must not exceed paver production to ensure consistent delivery and keep the paver moving. Select one: True False - ANSWERSfalse. Truck production MUST exceed paver production to ensure consistent delivery and keep the paver moving. There are three different mix methods for mix design: Hveem, Marshall, and SuperPave.
