3rd Annual Roller-Compacted Concrete
Pavement: Design and Construction
October 24, 2006
Development and Application of Density
Testing Methods and Standards for RCC
Construction
3rd Annual RCC Conf.
October 24, 2006
Troxler Electronic
Laboratories, Inc.
Bob Joines
Southern Branch Manager
Main Office & Factory
3008 Cornwallis Road
P. O. Box 12057
Research Triangle Park, NC 27709
1-877-Troxler (1-877-876-9537)
Fax - 919-549-0761
www.troxlerlabs.com
3rd Annual RCC Conf.
October 24, 2006
Southern Branch Office
1121 Banbury Lane
Brentwood, TN 37027
Phone - 615-331-8537
Fax 615-331-8537
Pager – 800-520-0674
bjoines@troxlerlabs.com
Nuclear Gauges
& RCC
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Items for
Discussion
Today
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History
Standards
Procedures
Precision
Calibration
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3rd Annual RCC Conf.
October 24, 2006
History of Nuclear Gauges
1960 - 2006
3rd Annual RCC Conf.
October 24, 2006
History of Concrete Testing
Using Nuclear Gauges
Nuclear Gauges have been used to test concrete for over 35 years.
We were testing low-slump dense modified bridge decks and slip
form paving in the 1970’s. As RCC construction grew, it was just
natural to use gauges to measure RCC densities.
3rd Annual RCC Conf.
October 24, 2006
History of RCC
Density Test Standards
For many years RCC was the
Concrete stepchild when it
came to ASTM test methods
for density.
Standards written for other
materials had to be modified
for RCC use. We did not
have our own nuclear
density test methods.
3rd Annual RCC Conf.
October 24, 2006
History of RCC
Density Test Standards
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ASTM C1040, the standard
most referenced, was written for
testing fresh concrete, primarily
looking for honeycomb in slip
form paving.
D2922, the nuclear gauge
density test method standard
most used, is a soils standard.
Neither address specific RCC
conditions and problems.
3rd Annual RCC Conf.
October 24, 2006
History of RCC
Density Test Standards
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In 2002, ASTM Subcommittee C9.60, Testing of Fresh
Concrete, advised Subcommittee C09.45 that C1040 was no
longer being used to test fresh concrete so it was going to be
balloted for withdrawal.
Since C1040 was being referenced in many RCC
specifications, C09.45 assumed ownership of the standard in
2003 and made minor revisions in it, including a name change.
One significant change we made was C09.45 developed a
Precision Statement for RCC which we will discuss later.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
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As the use of RCC grew, it was apparent that a
nuclear gauge density standard specifically for RCC
was needed. Committee C09.45 felt the industry
needed a test method that addressed what we
considered RCC specific issues.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
o
We also wanted to keep our standard as close as
possible to the nuclear gauge standards for Soils
and Asphalt in regards to equipment and calibration
requirements. We did not want confusing
requirements since the same technicians and
equipment would often be used for all three
materials.
3rd Annual RCC Conf.
October 24, 2006
Developing an ASTM
Standard Test Method
for RCC - Procedures
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ASTM Committee C09 on Concrete and Concrete Aggregates has
jurisdiction of over 155 standards, published in the Annual Book
of ASTM Standards, Volume 04.02. C09 has 29 technical
subcommittees that maintain jurisdiction over these standards .
Committee Scope:
o
(1) The assembling and study of data pertaining to the properties of
hydraulic-cement concrete and its constituent materials, including the
study of the effect of characteristics of materials and mixtures on the
properties of concrete; and (2) the development of standards for
concrete and for the constituent materials of concrete (except cement),
as well as for certain related materials, such as materials used in curing.
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Subcommittee C09.45 on Roller-Compacted Concrete is under
the direction of C09.
3rd Annual RCC Conf.
October 24, 2006
Developing an ASTM
Standard Test Method
for RCC - Procedures
o
C09.45 Subcommittee on
Roller Compacted Concrete:
Chairman:
Dennis Clute
USDA-NRCS
Fort Worth, TX
817-509-3765
dennis.clute@ftw.usda.gov
3rd Annual RCC Conf.
October 24, 2006
ASTM C09.45
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Next Committee Meeting:
Monday, December 4, 2006
10:00 AM - 12:00 Noon
Hyatt Regency Atlanta
265 Peachtree Street
Atlanta, GA 30303
3rd Annual RCC Conf.
October 24, 2006
Developing an ASTM
Standard Test Method
for RCC - Procedures
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First Step - Set up a Work Item with a Task Group
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WK1258 - Test Method of Roller-Compacted Concrete by Nuclear
Methods (Shallow Depth)
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Scope: This test method describes the procedures for measuring the
in-place density and water (moisture) content of roller compacted
concrete (RCC) by use of nuclear equipment. The density of the
material may be measured by direct transmission, backscatter, or
backscatter/air-gap ratio methods. Measurements for water (moisture)
content are taken at the surface (backscatter mode). In-place density
tests and moisture contents are required as part of a quality control
field testing program. This method will standardize the procedure to
be used.
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Second Step - Ballot Action
3rd Annual RCC Conf.
October 24, 2006
Developing an ASTM
Standard Test Method
for RCC
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Recently, ASTM Soils subcommittee D18.08
developed a new combined nuclear gauge density
and moisture standard (D6938) with the intent to
replace the current standards D2922 (density) and
D3017 (moisture).
C09.45 will be using D6938 as a basis for
developing its new standard.
The testing procedures will be RCC specific but the
subcommittee hopes by keeping the format similar
the users will find it less confusing.
We hope for quick review and approval.
3rd Annual RCC Conf.
October 24, 2006
Developing an ASTM
Standard Test Method
for RCC
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o
o
Some of the items we will be working on include
correlating gauge results with other methods such
as sand cone, core, beams, cylinder, test block, and
control strip results.
Even though Subcommittee C09.60 wanted to drop
their standard, we feel this new standard should
also provide guidance for testing fresh concrete.
Once the new standard is approved, we may
recommend that C1040 be withdrawn and replaced
by the new standard.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
Moisture (Water) Content
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We may not have nuclear moisture testing requirements
specified but since moisture content is critical to obtaining
proper density we want to address it in this standard.
It can be used as an indication of the uniformity and workability
of RCC. This can affect density.
Moisture content is a function of time due to evaporation and
chemical hydration. This will affect dry density
measurements.
Gauge moisture measurements should be used as an estimate
only.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
o
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Other Items for consideration include Test
Pads (Test Strips).
Nuclear Gauges can be used to establish
roller patterns and the optimum number of
passes.
Different equipment and methods can be
tried to determine which works best.
A control strip maximum target density
can be determined based upon the
materials, conditions, and equipment
available.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
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Advantages include being able to calibrate a gauge
to the material on a test strip.
Cores or beams taken from the test strip can be
used to verify gauge measurements and verify
material density versus RCC cylinders.
Testing at depths on the same site can be used to
evaluate the effectiveness of compaction efforts
throughout the full depth of the lift.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
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The committee recognizes that using test sections
has its benefits but can lead to other problems.
Results can be verified by other tests methods but
often may be different from lab methods.
This method cannot be used in lab design phase.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
o
o
A Test Block may be
recommended as a field
gauge calibration tool.
It can be used as an ongoing verification tool.
TEST BLOCK
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
o
o
Determining Target Density by lab methods may be
considered the most preferred option.
A calculated Maximum Theoretical Air-Free Density
can provide useful information and can be used in
the design phase.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
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o
o
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Because of similarities in materials, ASTM Soil
Proctor Tests D698 or D1557 are frequently
used to determine maximum dry density and
optimum moisture of RCC.
Experience has shown that the Modified Proctor
Test (D1557) works best with RCC.
95% to 98% of the Proctor Density is typically
specified. Additional verification is often
required.
These methods can also be used in the design
phase.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
o
o
Determining Target Density by lab cylinders may
also be an option.
Compacted RCC control Cylinders (ASTM C1176 or
C1435) may provide more consistent results.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
o
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The goal of the subcommittee is to develop a useful
nuclear gauge test method for quality control and
acceptance testing of RCC.
The subcommittee does not want to require any one
method for determination of a target density but to
define limitations of each as applied to the proposed
test methods.
The agency writing the specifications will always
have the ultimate choice of test methods and target
requirements.
3rd Annual RCC Conf.
October 24, 2006
Developing a Test
Standard for RCC
o
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ASTM requires that the subcommittee develop
Precision Statements for its Test Method Standards.
This requires a series of Round-Robin Tests.
C09.45 conducted a “modified” round-robin testing
program on a USDA-NRCS construction site in
Texas in 2004 for Test Method C1040.
The procedures used were also the procedures to
be specified in the proposed new standard.
The new standard will be one of a very few that has
a valid precision statement before it becomes an
approved standard.
3rd Annual RCC Conf.
October 24, 2006
Round Robin Test Program
ASTM C 1040 Round Robin Test Program Conducted
March 23, 2004 on Salado Creek Site 15, San Antonio, TX
3rd Annual RCC Conf.
October 24, 2006
Round Robin Test Program
3rd Annual RCC Conf.
October 24, 2006
Round Robin Test Program
3rd Annual RCC Conf.
October 24, 2006
Round Robin
Test Program
3rd Annual RCC Conf.
October 24, 2006
3rd Annual RCC Conf.
October 24, 2006
GAUGE THEORY
3rd Annual RCC Conf.
October 24, 2006
How gauges use radiation to
measure density and moisture
Nuclear Gauge Calibration
110 pcf
1760 kg/m3
Magnesium
3rd Annual RCC Conf.
October 24, 2006
Magnesium
Aluminum
134 pcf
2157 kg/m3
Aluminum
164 pcf
2640 kg/m3
Daily Standard Counts
Previous Daily Standard Counts
Density Counts – Moisture Counts
Avg.
3242
3250
3238
3247
3244
655
660
654
655
656
Today’s Counts
3255
658
0.3%
0.3%
3rd Annual RCC Conf.
October 24, 2006
Gauge Operation
A smooth surface
is needed
3rd Annual RCC Conf.
October 24, 2006
Fill Surface Voids
with native fines
Gauge Operation
3rd Annual RCC Conf.
October 24, 2006
Drive Pin 2” Deeper
Than Test Depth
Gauge Operation
Remove Pin Carefully
3rd Annual RCC Conf.
October 24, 2006
Mark Test Site for
Gauge/Pin Alignment
Gauge Operation
The “Troxler Method”
Align gauge. Push Rod into
Access Hole
3rd Annual RCC Conf.
October 24, 2006
Always make sure
gauge is pushed
back.
Gauge Operation - RCC
Proper Test
Procedures
Result in
Accurate Results
3rd Annual RCC Conf.
October 24, 2006
USDA NRCS RCC Dam
THE END
QUESTIONS?
3rd Annual RCC Conf.
October 24, 2006
Troxler Electronic Laboratories, Inc.
The leader in construction test equipment
THANK YOU!
For more information
contact us at:
1.877.TROXLER
(1.877.876.9537)
www.troxlerlabs.com
3008 Cornwallis Rd., PO Box 12057
Research Triangle Park, NC 27709
Fax: 919.549.0761
3rd Annual RCC Conf.
October 24, 2006