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Instruments help
contractors and inspectors
determine the quality of new pavement.
Troxler Electronic Laboratories
Directly measures density and bulk specific gravity
 Troxler says its CoreReader uses newly developed technology to directly
measure bulk-specific gravity as well as the density of lab-compacted
asphalt specimens or field-compacted core samples. The accuracy and
precision of direct measurement, says Troxler, ensures the reliability of
the specimen density and air void content of samples.
The company says its CoreReader eliminates the need for the water bath
and for the expense associated with coatings and wrappings. Troxler also
claims that direct measurement of the specific gravity of the asphalt
eliminates the need for mass to volume ratio estimations, as well as the
unreliable volume approximations inherent in current dimensional analysis
and water displacement methods.
Troxler says an independent study of the CoreReader by the Highway
Materials Lab at North Carolina State University found a standard deviation
of 0.0018 among 108 specimens and showed that the unit is more precise than
other methods currently being used.
Click 16 on ROADFAX card
Humboldt Manufacturing
Measures structural stiffness rather than density
 Humboldt’s Geogauge allows contractors and engineers to continuously
take direct readings of a material’s structural stiffness during
compaction to maintain critical uniformity and consistency. The company says
that in evaluating the compaction via structural stiffness instead of
density, the quality of the pavement system will be enhanced, increasing its
life expectancy and life-cycle costs. Applications include: compaction of
subgrade, subbase, and base to performance specifications; monitoring the
strength gain of lime, cement, fly-ash, and polymer stabilized materials;
monitoring compaction of trench or utility backfills to previous or
surrounding properties; and monitoring the compaction of asphalt and cold
in-place recycling to peak properties to prevent wasted effort and damaging
over-compaction.
Click 11 on ROADFAX card
Gilson Company
10-minute field test for permeability
 Gilson’s AP-1 falling-head asphalt permeameter uses Darcy’s Law to
determine the rate of water flow through asphalt pavement in-place. The
company says this design was selected by the National Center for Asphalt
Technology for its close correlation with laboratory test results when using
the protocol developed at the center.
Gilson says studies have shown that Superpave mixes can be permeable to
water even when compacted to an acceptable air void ratio; the company’s
field testing permeameter allows on-the-spot, accurate estimation of
permeability, eliminating the need for coring, patching, and lab testing.
Corrections to the mix and placement procedures can be implemented right
away, says Gilson.
Testing and calculations can be completed in 10 to 15 minutes by a single
technician following a simple procedure, according to the company.
Click 12 on ROADFAX card
Pavement Technology Inc.
Robotic truckload sampling
 PTI's robotic truck sampling device safely captures a representative
sample of asphalt or aggregate from a haul vehicle and deposits the sample
into a specimen container. The unit uses a telescopic arm with an 8-inch
heated probe head that submerges inside the hump of material. Typical sample
size is 30 to 35 pounds and sampling time is about one minute. Sampling
Device allows contractors to run material closer to the job mix formula and
avoid costly penalties.
Click 14 on ROADFAX card
TransTech Systems
Density gauge operates in compaction or air voids mode
Operating simplicity and a host of new features hallmark TransTech’s
non-nuclear density gauge, the Model 301 Pavement Quality Indicator. New
features include advanced software which simplifies operations even more,
and an easy-to-view screen that enhances readings even in bright sunlight.
Operational features include the ability to measure density in a percent
compaction mode as well as a percent air voids mode. There is also a
segregation mode which helps the contractor find problem areas on site.
TransTech calls the 301 a fast, accurate tool for making rapid density
measurements across the length and width of the mat. The company especially
recommends it for tender mix situations where the roller operator must have
real-time feedback on mix compaction. The unit has a built-in mat
temperature sensor, which provides fast readings in direct correlation with
density.
Click 17 on ROADFAX card
Spectronics Corporation
Quick field tests for alkali-silica reactivity
 Spectronics Corporation’s exclusive UV viewing system allows inspectors
to quickly check concrete for alkali-silica reactivity in the field. The
Spectroline model ASR-260 kit is a portable darkroom that uses shortwave UV
light and a chemical reagent to instantly reveal the presence of ASR gel
with a bright flourescent glow. Any cracks can be quickly repaired before
they cause serious damage. The ASR-260 kit is used by the U.S. Army Corps of
Engineers and the U.S. Federal Highway Administration.
Click 27 on ROADFAX card
TA Instruments
Two new dynamic shear rheometers
TA Instruments has announced a series of dynamic shear rheometers
designed for asphalt binder characterization in accordance with AASHTO
specifications and those being considered by NCHRP 9-10. In addition to the
company’s established CSA II, the series includes two new products, the AR
500 and AR 2000 Asphalt Analyzers.
The CSA II performs AASHTO TP5, PP6 and MP1 tests. The AR 500 uses the
company’s Environmental Test Chamber for more rapid analysis of those
tests. Both products can perform the rutting test proposed by NCHRP 9-10.
The AR 2000 is a research-grade dynamic shear rheometer that performs the
AASHTO binder tests, the rutting and fatigue tests proposed by NCHRP 9-10,
and can also analyze bars of asphalt mix in torsion.
Click 18 on ROADFAX card
A&D Weighing
Industrial balances use hybrid sensor technology
GP Series industrial balances from A&D Weighing are engineered with
patented hybrid sensor technology for applications including sieving and
core sampling analysis, aggregate testing, and quality control. Features
include IP-65 rating, automatic self-calibration with internal calibration
mass, and detached display on specified models. Eight capacities and
resolutions are available ranging from 12kg x 0.1g to 101Kg x 1g.
Click 28 on ROADFAX card
Dynatest
Measures pavement deflection accurately
Dynatest says its Model 8000 FWD Falling Weight Deflectometer lets the
engineer determine a deflection basin caused by a controlled load with
accuracy, and resolution superior to other test methods. It is
non-destructive, accurate, and fast, recording up to 60 test points per
hour. It can be operated by a single individual.
The Model 8081 HWD is a heavier loading version of the FWD, for
simulating heavy aircraft.
Click 23 on ROADFAX card
Rotex
Automatic sieve analysis for aggregate
The new Gradex 3000 particle size analyzer from Rotex Inc. is designed to
improve or expand quality control programs via fully automatic sieve
analysis for the gradation of aggregate material. The device is engineered
to classify materials including sand, gravel, or crushed stone. The unit is
equipped with an auto-feed option to free technicians for cycles of up to
six samples. The classifier analyzes up to 13 fractions utilizing a stack of
standard 12-inch-diameter, half-height, round test sieves that can be
changed to meet specific test requirements.
Click 24 on ROADFAX card
Pine Instrument Company
Rotary asphalt wheel tester introduced
Late last year, Pine introduced its Rotary Asphalt Wheel Tester, which
uses three Hamburg-style wheels to continuously rotate the specimen. Its
unique design takes advantage of the shape of Superpave Gyratory Compactor
specimens and pavement cores. Each rotation of the specimen provides three
load cycles, speeding up testing time for laboratories, highway departments,
and contractors.
By traveling around the outside of the specimen, the rotary tester
creates an infinite wheel path which eliminates the need to mount multiple
specimens to perform the test.
Wheel mounting is fast and easy. Wheel velocity is constant, uni-directional,
and easily adjusted from the front control panel.
Click 19 on ROADFAX card
Instron
Family of testing systems for asphalt
Instron’s Model 5525 Asphalt Pro is designed to measure the strain at
failure for asphalt binders at very low temperatures, in accordance with
AASHTO TP3 and ASTM D6723.
Other systems in the Instron family include the IDT-3 indirect tension
test, the FastTrack 8800 system which performs axial cyclic stress testing
to determine the characteristics of pavement materials, and the single
column universal tester used to determine the toughness and tenacity of
bituminous materials based on a static pull test.
Click 22 on ROADFAX card
Pavement Technology Inc.
Mobile asphalt QC/QA labs
 PTI, a division of Astec Industries, offers mobile and skid-mounted
pavement laboratories that can be used for asphalt, concrete, aggregate, and
soils testing. Each lab is custom-designed to meet individual customer
needs. PTI says its mobile labs are built to last 25 to 30 years and most
include an office, restroom, testing rooms, storage, and noise abatement
rooms.
Click 15 on ROADFAX card
ATS Rheosystems
Comprehensive instrumentation and support services
ATS RheoSystems bills itself as a comprehensive instrumentation and
service support company specializing in rheometer and viscometer design and
applications. The company’s product line also includes dynamic shear
rheometers, dynamic mechanical thermal analysis equipment, and materials
characterization instrumentation. The company also provides third-party
technical service and support, contract testing, consulting, and
applications training.
Click 20 on ROADFAX card
Gilson Company
Measures aggregate abrasion resistance and durability
Gilson’s Micro-Deval test measure abrasion resistance and durability of
aggregates in the 9.5 to 19mm size range. A presoaked coarse aggregate
sample is placed in a steel jar with a 5000-gram abrasive charge of 9.5mm
stainless steel balls and water, then rotated at 100 rpm for two hours.
Aggregate quality is determined by percentage loss in gradation.
According to Gilson, the Micro-Deval method is easier to run and costs
less than traditional methods because it uses smaller equipment, lower
sample quantities, and a simpler procedure.
Click 13 on ROADFAX card
Bohlin Instruments
New high-temperature binder testing equipment
The Visco 2000, Bohlin’s newest asphalt binder testing equipment, is
specifically designed to perform ASTM D4402 high temperature testing of
asphalt binder.
Also available from Bohlin are the DSRII rheometer, the ADS rheometer,
and its BDT direct tension system.
Click 21 on ROADFAX card
Halliday Technologies
New roadway friction tester for maintenance trucks
 The Roadway Friction Tester was developed by Halliday Technologies to
allow a maintenance vehicle to measure the road friction while, at the same
time, performing its normal duties, such as snow removal or road surface
treatment. The system uses the, already onboard, hydraulic system to deploy
and retract the wheel which is located in front of the drive axle underneath
the vehicle. The system is designed to feed data showing road friction to
the driver via a display in the cab of the truck. The system has worked
flawlessly in tests and has had no adverse effect on the vehicle systems or
handling.
Click 25 on ROADFAX card
Reprinted from Better Roads February 2003 issue
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