Troxler 3430 User Manual

Manual of Operation and Instruction

Model 3430

(and Model 3430-M)

Surface

Moisture-Density

Gauge

Troxler Electronic Laboratories, Inc.

3008 Cornwallis Rd. • P.O. Box 12057

Research Triangle Park, NC 27709

Phone: 1.877.TROXLER

Outside the USA: +1.919.549.8661

Fax: [phone]

www.troxlerlabs.com

The Troxler Model 3430 Surface Moisture-Density Gauge

is protected by U.S. and Foreign Patents

Copyright © 1990–2006

Troxler Electronic Laboratories, Inc.

All Rights Reserved

No part of this manual may be reproduced or transmitted in any
form or by any means, electronic or mechanical, including
photocopying, recording, or information storage and retrieval
systems, for any purpose without the express written permission of
Troxler Electronic Laboratories, Inc.

Fantastic is a trademark of Dow Consumer Products, Inc.
Federal Express is a registered trademark of the Federal Express

Corporation.

409 is a trademark of the Clorox Company.
Magnalube-G is a registered trademark of Carleton-Stuart

Corporation.

WD-40 is a registered trademark of the WD-40 Company.

PN 105305
December 2006
Edition 8.1

ii

TROXLER SERVICE CENTERS

Troxler Corporate Headquarters

3008 Cornwallis Road

P.O. Box 12057

Research Triangle Park, NC 27709

Phone: 1.877.TROXLER (1.877.876.9537)

Outside the U.S.A.: +1.919.549.8661

Fax: [phone]

Web: www.troxlerlabs.com

Technical Support

Phone: 1.877.TROXLER (1.877.876.9537)

E-mail: [e-mail]

Midwestern Branch Office

1430 Brook Drive
Downers Grove, IL 60515
Fax: [phone]

Western Regional Branch Office

11300 Sanders Drive, Suite 7
Rancho Cordova, CA 95742
Fax: [phone]

Southwestern Branch Office

2016 East Randol Mill Road
Suite 406
Arlington, TX 76011
Fax: [phone]

To locate an independent, Troxler-authorized service
center near you, call 1.877.TROXLER (1.877.876.9537).

Florida Service Center

2376 Forsyth Road
Orlando, FL 32807
Fax: [phone]

Troxler European Subsidiary

Troxler Electronics GmbH
Gilchinger Strasse 33
D.82239 Alling nr. Munich, Germany
Phone: ++49.8141.71063
Fax: ++49.8141.80731
E-mail: [e-mail]

NOTE

Model 3430 iii

CAUTIONS AND WARNINGS

Units intended for use in countries that are members of the
European Community are shipped with a CE-approved AC
adapter, Troxler bin number 108354.

Gauge cover is to be removed by trained service personnel
only. There are no user-serviceable components inside. Note
that components behind the cover can have voltage
potentials in excess of 50 volts during normal operation of
the gauge.

Appendix A, Radiation Theory and Safety should be read
carefully and understood before using the gauge.

See page C-8, Alkaline Battery Use.

The source rod should automatically retract to the SAFE
position when the gauge is lifted by the handle.

See page C-12, Tungsten Sliding Block.

iv

EU DECLARATION OF CONFORMITY

Application of Council EMC Directive 89/336/EEC and Low Voltage
Directive 73/23/EEC

Standards to which Conformity is Declared:

EN 61010-1
EN 55011 Group 1, Class A
EN 50082-2

An EMC Technical Report/Certificate has been issued in accordance
with Part IV (Reg 50) of the UK Regulations (SI 1992 No. 2372) by a UK
appointed Competent Body, namely,

Interference Technology International Limited

41-42 Shrivenham, Hundred Business Park

Shrivenham, Swindon, Wiltshire SN6 8TZ

Certificate Number C283TRO.1ABS Dated 16th January 1997
Troxler Document Number 108205

Manufacturer: Troxler Electronic Laboratories, Inc.
PO Box 12057
3008 Cornwallis Road
Research Triangle Park, North Carolina 27709
USA

Apparatus: Model 3430 Surface Moisture-Density Gauge

Year of Declaration: 1997 (Original)

2006 (Corrected)

Model 3430 v

HOW TO USE THIS MANUAL

Congratulations on the purchase of the Troxler Model 3430
Surface Moisture-Density Gauge.

The Model 3430 Manual of Operation and Instruction contains
information on how the Model 3430 operates, and provides
directions on the use of this gauge. Site selection, basic parameter
setup, moisture and density determination, storage, and advanced
operations are included, along with radiological information and
system troubleshooting.

GUIDE TO SYMBOLS AND FORMATTING

Throughout this manual, symbols and special formatting are used to
reveal the purpose of the text as follows:

CAUTION

NOTE Indicates important information that must be read to

♦ Diamonds indicate a list of things needed (such as

 Check marks indicate the performance of an action.

 Triangles indicate that more than one option is

〈KEY〉 Angle brackets and a different typestyle indicate a

DISPLAY A different typestyle is also used to indicate text

Indicates conditions or procedures that, if not
followed correctly, may cause personal injury or
equipment damage.

ensure proper operation.

equipment) or things to know.

With lists of check marks, follow the instructions in
the order of the check marks.

available. Carefully select the option that applies.

key or character (number or letter) to press on the
control unit keypad. For example, “Press 〈STD〉”
means to press the key labeled STD.

displayed on the control unit.

vi

TABLE OF CONTENTS

CHAPTER 1. INTRODUCTION TO THE MODEL 3430

Introduction....................................................................................1-2

Gauge Parts and Accessories.........................................................1-4

Unpacking and Inspection .............................................................1-6

Storage Site Selection....................................................................1-7

CHAPTER 2. THEORY OF OPERATION

Density...........................................................................................2-2

Moisture.........................................................................................2-5

CHAPTER 3. OPERATING THE GAUGE

The Keypad....................................................................................3-2

Source Rod Positions.....................................................................3-4

Daily Inspection.............................................................................3-5

Turning the Gauge On ................................................................... 3-6

Gauge Parameter Setup..................................................................3-7

Taking the Standard Count..........................................................3-10

Site Preparation/Gauge Positioning.............................................3-12

Taking a Measurement – Soil Mode............................................ 3-15

Taking a Measurement – Asphalt Mode......................................3-17

CHAPTER 4. ADVANCED GAUGE OPERATION

Offsets............................................................................................4-2

Special Calibrations.......................................................................4-7

Thin Layer Measurements...........................................................4-11

CHAPTER 5. SPECIAL FUNCTIONS

Recall.............................................................................................5-2

Offset .............................................................................................5-2

Stat Test.........................................................................................5-2

Drift Test........................................................................................5-5

Special Calibration.........................................................................5-7

Specific Gravity.............................................................................5-7

Voidless Density............................................................................5-8

Set Units.........................................................................................5-8

Calibration Constants.....................................................................5-9

Memory Reset..............................................................................5-10

Test Reading................................................................................5-10

Language......................................................................................5-11

Model 3430 vii

TABLE OF CONTENTS (Continued)

APPENDIX A. RADIOLOGICAL INFORMATION

Radiation Theory...........................................................................A-2

Radiation Safety............................................................................A-5

APPENDIX B. SPECIFICATIONS

Measurement.................................................................................B-2

Radiological ..................................................................................B-4

Electrical........................................................................................B-5

Mechanical ....................................................................................B-6

APPENDIX C. TROUBLESHOOTING AND SERVICE

Troubleshooting.............................................................................C-2

Battery Charging ...........................................................................C-8

Mechanical Maintenance.............................................................C-10

Leak Testing................................................................................C-15

Replacement Parts.......................................................................C-16

Returning the Gauge for Service.................................................C-26

Troxler Service Centers............................................................... C-28

APPENDIX D. TRANSPORTATION AND SHIPPING

U.S. Requirements.........................................................................D-2

Canadian Shipping Requirements .................................................D-4

APPENDIX E. STANDARD COUNT LOG

APPENDIX F. UNIT CONVERSION

Measurement Units........................................................................F-2

Radiological Units......................................................................... F-2

INDEX

WARRANTY

viii

LIST OF FIGURES

Figure

1-1 Model 3430 Gauge and Accessories..........................1-5

2-1 Direct Transmission Geometry ..................................2-3

2-2 Backscatter Geometry................................................2-3

2-3 Backscatter Surface Density Effects (Top Layer

Effect Curves) ............................................................2-4

2-4 Effect of Moisture on Depth of Measurement............2-6

3-1 Model 3430 Keypad...................................................3-2

3-2 Source Rod Positions .................................................3-4

3-3 Standard Count Position...........................................3-11

3-4 Drill Rod Positioning ...............................................3-12

3-5 Marking the Test Area .............................................3-13

3-6 Voids Illustration......................................................3-16

A-1 Diagram of an Atom..................................................A-2

A-2 Variation of Radioactive Emission ...........................A-4

A-3 Effect of Distance on Exposure................................. A-6

A-4 Model 3430 Gauge and Transport Case.................... A-8

C-1 Removing the Tungsten Sliding Block ................... C-13

C-2 3430 Gauge Assembly ............................................ C-17

C-3 3430 Gauge Base M echanical Assembly................ C-19

C-4 3430 Source Rod Handle Assembly........................ C-19

C-5 3430 Gauge Preamplifier Assembly ....................... C-21

C-6 3430 Gauge Scaler Assembly ................................. C-23

Title Page

Model 3430 ix

LIST OF TABLES

Title Page

Table

3-1 Model 3430 Keypad Functions.................................. 3-3

4-1 K Values for Thin Lift Overlays.............................. 4-13

A-1 Radiation Profile for Model 3430 Gauge...................A-9

A-2 Radiation Profile for Model 3430-M Gauge............A-10

x

ATTENTION GAUGE OWNER

This gauge contains functions that require an ACCESS
CODE. This code must be entered before these functions may
be used. For more information on using the access code refer
to the specific function in Chapter 5.

The ACCESS CODE for this gauge is:

4678

This page should be removed if the access code is not to be
distributed to other parties or users of this gauge.

Model 3430 xi

NOTES

xii

CHAPTER 1

INTRODUCTION TO THE MODEL 3430

This chapter provides a general introduction to the Model 3430
Surface Moisture-Density Gauge and its applications. Also included
are a list of the gauge parts and accessories, instructions for
unpacking and inspecting the system, and guidelines for site
selections.

CONTENTS

Introduction....................................................................................1-2

Gauge Parts and Accessories.........................................................1-4

Unpacking and Inspection .............................................................1-6

Storage Site Selection....................................................................1-7

INTRODUCTION

Model 3430 1-1

INTRODUCTION

The Model 3430 Surface Moisture-Density Gauge can quickly and
precisely determine the moisture and density of soils, soil bases,
aggregate, concrete and asphaltic concrete without the use of core
samples or other destructive methods.

Using direct transmission or backscattered gamma radiation, the
3430 gauge determines the density of materials by counting the
number of photons emitted by a cesium-137 source. Geiger-Mueller
(G-M) detectors located in the gauge base detect the gamma
radiation and a microprocessor converts the counts into a density
reading.

Using the principle of neutron thermalization, the Model 3430
determines the moisture content of soils and soil-like materials.
Hydrogen (water) in the material slows neutrons emitted from an
americium-241:beryllium source (or californium-252 in the Model
3430-M). Helium-3 detectors located in the gauge base detect the
slowed neutrons.

The nuclear method of testing density and moisture has been
approved by the American Society of Testing and Materials
(ASTM). The Model 3430 meets or exceeds all the requirements of
ASTM Standards C1040, D2922, D2950, and D3017.

Some information contained in this manual is used in training
courses offered by Troxler Electronic Laboratories, Inc. and to assist
purchasers in obtaining a Radioactive Materials License from the
U.S. Nuclear Regulatory Commission or an Agreement State.
Owners of this gauge must maintain a current radioactive materials
license as long as they own the gauge, even if it is in storage and not
actively being used.

1-2

Any licensing issues discussed in this manual are for the United
States. To purchase a Model 3430 in Canada, owners must obtain a
radioisotope license from the Canadian Nuclear Safety Commission
(CNSC). The owner should obtain copies of the CNSC Regulations
and the Transportation of Dangerous Goods Act and Regulations.
This manual provides a guide to Canadian shipping requirements in
Appendix D.

Owners are encouraged to require study of this manual by users
before allowing any use of the instrument. To monitor exposure to
radiation, personnel should wear a dosimeter while operating or
cleaning the gauge. The sections of the manual covering radiation
safety should be required reading for all operators and potential
operators. If these sections are not completely understood, users

should seek assistance from Troxler, an appointed Troxler
representative or others designated within the user
organization. Additional radiation safety information is available

by attending a Troxler Nuclear Gauge Training Course.

As changes are made to local, state, and federal regulations on a
continuing basis, the owner/user must maintain a knowledge of
these regulations. The responsibility for compliance ultimately falls
upon the owner. The owner may also wish to purchase and
subscribe to Titles 10 and 49 of the Code of Federal Regulations in
addition to applicable local/state regulations.

NOTE

This manual also contains radiological information for
the Model 3430-M. The 3430 and 3430-M have the same
functions and operational aspects but different neutron
sources.

INTRODUCTION

Model 3430 1-3

GAUGE PARTS AND ACCESSORIES

Figure 1-1 shows the Model 3430 gauge and its accessories. Use
this figure and the list below to identify the gauge and parts as they
are unpacked.

1. The Gauge is a portable instrument containing all electronic

modules, battery packs, detectors, and radioactive sources.

2. The Reference Standard Block provides a uniform reference

material for gauge adjustment to compensate for source decay.

3. The Scraper Plate/Drill Rod Guide is used to prepare the test

site and aid in guiding the drill rod into the soil.

4. The Drill Rod is used to prepare a hole for a direct transmission
reading. Do Not Use the Source Rod For This Purpose!

5. Two Chargers/Adapters are supplied: one for DC (12 VDC)
and one for AC (115/230 VAC 50/60 Hz.)

6. The Transport Case is a container designed for transportation
of the gauge and associated parts.

7. The Extraction Tool provides a means of removing the drill
rod from the test material after use.

1-4

INTRODUCTION

Figure 1-1. Model 3430 Gauge and Accessories

Model 3430 1-5

UNPACKING AND INSPECTION

Upon receipt of the gauge from the factory, a complete inspection
and inventory should be performed. If the shipping case, any other
part of the container, or the gauge appears to be damaged, notify the
carrier and your Troxler Representative immediately.

For shipping to another location or back to the factory, save the box
and any packing material. For shipping instructions and regulations,
please see Appendix D.

Check to see if the following literature and components have been
included:

♦ Manual of Operation and Instruction
♦ Gauge Warranty
♦ Source Certificate
♦ 3430 Gauge
♦ Scraper Plate
♦ Drill Rod
♦ AC Battery Charger
♦ DC Charger/Adapter
♦ One handle lock with keys

Lift the gauge from the case. Inspect the gauge for damage. Check
the lock on the handle. Ensure the keys fit the lock.

1-6

STORAGE SITE SELECTION

When deciding where to store the gauge, take into consideration the
rules governing the storage of low-level radioactive devices that are
set forth by your regulatory agency and the conditions of your gauge
license.

Ë The handle should be locked and the gauge stored in its

transport case.

Ë It is recommended that the gauge and transport case be stored at

least 15 ft (5 m) from work areas, preferably in a locked
closet/storage area in a dry location (indoors).

Ë The storage area should be marked with a radiation sign that

reads “CAUTION RADIOACTIVE MATERIALS” (can be
obtained from Troxler).

Ë The storage of a nuclear gauge in a motor vehicle is not

recommended.

INTRODUCTION

Model 3430 1-7

NOTES

1-8

CHAPTER 2

THEORY OF OPERATION

This chapter contains a brief description of the theory of operation
of the Model 3430 Surface Moisture-Density Gauge. The direct
transmission and backscatter modes of operation are illustrated
along with a brief explanation of the cesium-137 source, americium­241:beryllium or californium-252 source, and detector geometry.

CONTENTS

Density...........................................................................................2-2

Moisture.........................................................................................2-5

OPERATION THEORY

Model 3430 2-1

DENSITY

The Troxler Model 3430 gauge utilizes two modes of operation:
direct transmission mode (source rod extended into the material)
and backscatter mode. Figures 2-1 and 2-2 illustrate the two modes
of operation.

In direct transmission mode (Figure 2-1), the rod containing the
cesium-137 (8 mCi/0.3 GBq) source is lowered to the desired depth.
The detectors (G-M tubes) in the gauge base measure the radiation
emitted by the source rod. Gamma photons reaching the detectors
must first pass through the material, colliding with electrons present
in the material. In general, the lower the number of photons that
reach the detectors, the higher the material density.

In backscatter mode (Figure 2-2), the gamma photons that enter the
material must be scattered (or reflected) at least once to reach the
detectors in the gauge. With the rod locked in the first notch below
the SAFE position, the source and detectors are in the same plane,
referred to as the backscatter position. Photons emitted from the
source penetrate the material, and the detectors measure the
scattered photons. Shielding between the source and detectors
greatly reduces the number of photons reaching the detectors in a
direct path with the source.

While the direct transmission geometry measures the average
density of the material from the source to the surface, the
backscatter geometry yields an average heavily weighted by the
density close to the surface. Figure 2-3 shows two normalized top
layer effect curves, illustrating the percentages of photons at the
detectors for various depths. The two curves can be used to compute
the gauge response to layered material of different densities. For
example, the density of the top inch of a surface layer accounts for
approximately 52% of the backscatter density measurement.

2-2

OPERATION THEORY

Figure 2-1. Direct Transmission Geometry

Figure 2-2. Backscatter Geometry

Model 3430 2-3

Figure 2-3. Backscatter Surface Density Effects

(Top Layer Effect Curves)

2-4 Model 3430 2-5

MOISTURE

The Model 3430 gauge uses a 40 mCi (1.48 GBq) americium­241:beryllium neutron source to measure the hydrogen content
(consequently the water content) of the material. The 3430-M gauge
employs a 60 µCi (2.22 MBq) californium-252 source.

Neutrons emitted by the Am-241:Be (or Cf-252) source penetrate
the material and are thermalized (or slowed). Thermalization is the
process where neutrons are slowed to the point where further
collisions with hydrogen or other materials will not continue to slow
the neutron.

The 3430 gauge contains a helium-3 neutron detector that is
sensitive to thermalized neutrons. This detector is insensitive to
non-thermalized, or “fast” neutrons and, as a result, the counts
obtained are directly proportional to the amount of
hydrogen/moisture present in the material.

The depth of measurement, or depth at which 98% of the counted
neutrons pass before reaching the detector, is a function of moisture
content:

Depth (inches) = 11 – (0.17

Depth (mm) = 280 - (0.27

Therefore, the higher the moisture content in the material being
measured, the smaller the depth of measurement. The normalized
curve set shown in Figure 2-4 illustrates the effect of moisture
content on the depth of measurement.

×

M), where: M = moisture in pcf

or

×

M), where: M = moisture in kg/m3

OPERATION THEORY

Figure 2-4. Effect of Moisture on Depth of Measurement

2-6 Model 3430 3-1

CHAPTER 3

OPERATING THE GAUGE

This chapter explains the basic operation of the Model 3430 Surface
Moisture-Density Gauge. Instructions for conducting a daily gauge
inspection, setting gauge parameters, taking the daily standard
count, preparing the site, positioning the gauge, and taking moisture
and density measurements are included.

CONTENTS

The Keypad....................................................................................3-2

Source Rod Positions.....................................................................3-4

Daily Inspection.............................................................................3-5

Turning the Gauge On ................................................................... 3-6

Gauge Parameter Setup..................................................................3-7

Setting Measurement Units.....................................................3-7

Setting the Count Time ...........................................................3-8

Setting the Depth.....................................................................3-8

Selecting the Mode (Marshall/Proctor)...................................3-8

Taking the Standard Count..........................................................3-10

Site Preparation/Gauge Positioning.............................................3-12

Soil and Base Course Preparation.........................................3-12

Asphalt Surface Preparation..................................................3-14

Taking a Measurement – Soil Mode............................................ 3-15

Taking a Measurement – Asphalt Mode......................................3-17

GAUGE OPERATION

THE KEYPAD

Figure 3-1. Model 3430 Keypad

The keypad (Figure 3-1) of the Model 3430 Surface Moisture­Density Gauge consists of ten keys — an eight-function keypad and
the 〈ON/YES〉 and 〈OFF/NO〉 keys. The gauge is equipped with a
beeper to verify keystrokes. If a beep is not heard when a key is
pressed, the keystroke was not recognized and should be repeated.
The 〈ON/YES〉 and 〈OFF/NO〉 keys are used for responses to
specific questions displayed on the screen and to turn the gauge on
and off.

The up and down arrows allow the operator to scroll through
various function lists displayed by the gauge.

Table 3-1 provides a more detailed description of the individual
keys and the location in the manual where the functions are
described.

3-2 Model 3430 3-3

Table 3-1. Model 3430 Keypad Functions

KEYS

ON

YES

OFF

NO

↑

↓

MA
PR

TIME

STD

DEPTH

SPECIAL

DESCRIPTION PAGE

Turns on the gauge and answers Yes
to prompts.

Turns gauge off and answers No to
prompts

Scrolls the display up.
Scrolls the display down.
Allows entering or enabling of a

Proctor or Marshall value.
Allows the operator to change the

count time.
Use to access the Standard Count

mode.
Allows entry of the source rod depth. 3-8

Provides access to the Special
functions.

3-6

3-9

3-8

3-10

3-7, 4-3,
4-4, 4-7,

5-1

GAUGE OPERATION

START
ENTER

Starts a measurement or completes
answer entry.

SOURCE ROD POSITIONS

Figure 3-2 shows the available positions of the source rod.

NOTE

The source rod should always be in the SAFE position
when the gauge is not in use.

3-4

Figure 3-2. Source Rod Positions