HardTrack Mobile User Manual

Revision 5.1

Wake, Inc. reserves the right to alter any of its products or related published technical data
anytime, without notice.

Copyright© 2021 by Wake, Inc.

All rights reserved, including the right to reproduce this document or portions thereof in any form whatsoever, without the written consent of the copyright holder. For information, please contact Wake at:

Corporate Office
2885 Sanford Ave SW #27245, Grandville, MI 49418-1342 USA

Tel: US: (800) 957-5606  CA: (647) 931-6995                                       Fax: (877) 900-0189 

HardTrack Concrete Temperature & Maturity Monitoring System

2.1 Handheld EXPANSION PACK INSTALLATION

In addition, make sure that Windows Mobile Development Center or ActiveSync is configured to synchronize your handheld device’s “My Documents” folder. That way, every time you dock your handheld device, all the data files will be copied to your PC. This is the easiest way to view the exported files. It also maintains copies of HardTrack’s data files on your PC, where they can be backed up. It also makes it easy to restore all your HardTrack data files to your handheld device    

For more information on Windows Mobile Development Center and ActiveSync, please see the instruction in Section 11. HardTrack Desktop.

2.2 Handheld I-CARD INSTALLATION

The handheld device will come from WAKE with the i-CARD installed.  No further action is required.

2.3 HARDTRACK SOFTWARE INSTALLATION

Handheld Device:

(Handheld installation)

·       Installed Active Sync or Windows Mobile Device Center software on your PC.

·       Place the Handheld device in its cradle attached to the USB port of your  

PC.

·       Download the HardTrack Mobile Installation ZIP file to your PC with the link provided by WAKE

·       Remove the ".rename" from the end of the file name so that your laptop will recognize the file as a zip file.

·       With the handheld in the docking station, click on Windows Mobile:

·      Once you have the flash drive open, un-zip the file and copy the (3) folders that were un-zipped into the root of the Flash drive. 

·      If you are asked any questions regarding replacing files on the handheld device, always answer “Yes” 

·      Now perform the cold boot to install this version of the software: 

·       Hard/Cold reset: returns the unit to factory settings and re-installs the HardTrack software.  All of your data will be preserved.  

Once you have the correct key file installed, you can start up the HardTrack software. You will find it in both the Start menu and the Programs folder. Make sure that you have the i-CARD and Expansion Pack installed on your Handheld device before you attempt to connect to the i-CARD. If it pops up a message saying that it was unable to connect to the i-CARD, then you will have to figure out why it failed and then try again. There is an option you might want to set which automatically connects to the i-CARD every time the software is started. See the i-CARD options settings (Section 7.3.2).

In order to verify that you have a valid key file installed correctly on your machine, start up the software, and then, from the Tag menu, select “Scan For Tags”. If you get a message saying “Invalid KeyFile” then you are either missing the key file, or it doesn’t contain the correct key for your machine. Confirm that the correct key file is in “My Documents/Concrete Monitor”. If this fails to resolve the problem, please contact WAKE.

Bluetooth /USB Reader

If you purchased your tablet from Wake with your order for the Bluetooth/USB Reader, the HardTrack Software will be preloaded and installed on your tablet.  Wake Customer Care will provide you with your initial login credentials.

If you are installing the HardTrack Software on to your own tablet or laptop, please follow the instructions provided in this document:

Software installation for Tablet or Laptop with Bluetooth/USB Reader

Still cannot get the Reader to connect to the Table or PC?

2.4 TAG INSTALLATION

Wake recommends that you initialize the tags before pouring concrete over them. A tag that hasn’t been initialized may be in low sensitivity mode and once it’s buried in concrete, you won’t be able to talk to it.

2.4.1 WHERE SHOULD THE TAGS BE PLACED?

There are two sets of guidelines to follow. The first, the Industry Guidelines, are concerned with locating the tags so that they are measuring useful temperatures. The second, WAKE Concrete Maturity Monitor Tag Guidelines, are concerned with making sure that communication with the tags will be reliable.

Industry Guidelines

In general, tags should be placed between 2 and 6 inches from any exposed surface, or at the mid-depth of the section, whichever is less.

Your engineers should be able to tell you where they want the tags placed. Usually, this will be in locations where:

·       An estimation of the strength is desired.

·       Strength is critical, because of structural considerations or exposure conditions considerations.

·       The concrete is of a different thickness.

·       Critical temperatures are likely to be generated.

HardTrack Concrete Maturity Monitor Tag Guidelines

In order to optimize HardTrack’s ability to communicate with the buried tags, we provide

the following additional guidelines:

Note: to see the Red LED light, Scan for Tags, then select the Tag that you are working with and select Locate Tag on your handheld device and the Red LED will flash

·       Orientation  Although the tags have Omni-directional antennas, the tags work best when positioned parallel to the surface. We prefer to orient the tags so that you can see the red LED. Note that in a horizontal slab, the tag would usually be positioned as if it was lying down, and the red LED pointing straight up. This assumes that you plan to read the tag from above. However, if this is a vertical column or wall and you plan to read the tag from the side, then the tag should be placed such that the red LED points out the side, towards where you intend to read it from. It could be oriented either vertically or horizontally.

·       Depth  We recommend that standard tags be buried to a maximum depth of 8 inches from the surface from which you plan to read the tags from. If this is not possible, then you need to use a tag with a temperature probe. These external temperature probes can be buried at almost any depth and may extend to any location, but the tag must be buried according to the proceeding requirements. The tag could also be left outside the concrete, where it can easily be read and reused.

·       Line of Sight  HardTrack needs to be able to “see” the tags. If they are hidden behind a bundle of rebar, then communication will be marginal at best.

·       Attachment  The tags really should be tied down to something so that they don’t get washed away in the flood of concrete. By far the easiest method is to attach the tags to the rebar within the concrete. Use rebar wire ties, nylon cable ties or whatever is handy.

·       External Probe Tags  These tags are installed similar to standard tags, with the exception that the temperature is taken at the probe point. This allows the tag to be located anywhere that it can be clearly read, including above the surface. (If the tag is externally located, then it can be disconnected and re-used, sacrificing only the probe.)

You have:

·       The Handheld with the software installed within it, as well as the reader card installed or a tablet or laptop with HardTrack installed and the Bluetooth/USB Reader communicating with HardTrack.

·       Some Identec i-Q350 tags or i-Q350 TE tags with the external temperature probe.

3.1 STARTING THE SOFTWARE

Make sure that your computer’s clock is set accurately. HardTrack relies on this clock to timestamp temperature log files.

At this point, you are ready to start using HardTrack. Place the tags where you can see the LEDs. It is reassuring to see the LEDs flash when HardTrack is communicating with them. About 5 feet away from the Mobile Device works well, although you may need to be physically closer for the initial phase when the tags are still in their low sensitivity mode.

Start the software by tapping on the HardTrack icon, either in the Start Menu or in the Programs folder.

HardTrack displays a list of the tags in the current project. At this point in time, it will be empty because no project has been selected. The project name is set to “untitled”. Note that the “untitled” project cannot be saved.

A project groups a set of tags together. A project could be as small as a single slab of concrete with a single tag in it, or it could be as large as a mile of highway with a hundred tags in it. The expected size of a project would be something around 10 or 30 tags, all of which share the same set of concrete types (batches).

First we need to make sure we are connected to the i-CARD. Tap on the Options menu, then tap on the i-CARD menu item. The i-CARD Options window pops up.

If the Status is “NOT connected” as in the above example, then tap on the Connect button. A busy indicator will appear while the card is being configured. Make sure that the Communications Range is at Maximum, then tap on the OK button, and once again, a busy indicator appears, while the desired range is being set in the card. When completed, the window is popped down.

At this point, you should also make sure that the Autoconnect check box is checked. This ensures that HardTrack will connect with the i-CARD each and every time it is started.

And then tap on the Scan For Tags button. You will get a brief “Busy” indicator and then a list of the tags which responded to the scan will appear on the screen.

If you get an “Invalid Key File” message, then you either your key file is missing, or contains the wrong key code. Make sure that your key file is correctly installed (see Section 2.3) and if it still doesn’t work, then contact WAKE.

Your display will look similar to this one. If you have set your display options to display “Tag Location” instead of “Tag Id”, then you will have a list of “Unknown” tags. Once the tags are configured and named properly, then “Tag Location” display option is the more useful way of identifying tags, but until then, it is better to use “Tag Id”.

At this point, you would normally initialize each tag that you found. However, you could try reading the temperature log currently on each tag. There may or may not be one there, depending on the factory configuration of your tags. If you want to try, highlight a tag (tap on a row in the list), then go to the Tag menu and select Read Tag. A “Busy” indicator will appear, and the LED on the selected tag will flash intermittently for a few seconds. Go to the Temperature window section (7.2.6) to see how to view the log.

To initialize each tag, highlight it (tap on a row in the list), then go to the Tag menu and select Initialize Tag. A “Busy” indicator will appear, and the LED on the selected tag will flash intermittently for a few seconds. This operation makes sure that each tag is set up to work with HardTrack. Specifically, the tag is told to go to High Sensitivity mode (necessary for operation when buried in concrete) and is also commanded to start logging temperatures. This has no effect on the battery life and is a useful way to ensure that complete temperature records are always available.

Temperature Log Note:

Each time a tag is commanded to start logging temperatures, the temperature log is empty until the time period passes (default is 30 or 5 minutes, depending on your project duration setting) and the first measurement is added to it. This

means that any subsequent reads will FAIL until data has been added to the log. Do not panic, this is just the way that it works.

High Sensitivity Note:

Once the tag switches into high sensitivity mode, you are much more likely to be too close to the tag. If the logging fails to start, move a little farther away and try again.

To save these tags to a project, tap on the Project menu, and select Save As. Then type in the name you want the tags associated with.   Here the project has been saved as “WAKESlab” and contains two tags. The other information displayed is still zero because the tags need to be told about the concrete they are buried in: when it was poured and the kind of concrete it is. Once this information is known, HardTrack will update the display. HardTrack will also display values in red that have been defined as out of date, and should be updated by getting new data from the tag.

Now that we have a project with tags, we can access HardTrack’s other features. These other features are all tag specific; that is, they deal with only one tag, and It's associated concrete, at a time.

Best Practices - 

Initialize the Tags and Start logging on all Tags for a Project

3.3 TELLING A TAG ABOUT CONCRETE

HardTrack needs to know a few things about the concrete before it is able to determine how mature it is. Some of these things won’t be known until later, and some of them may change. This is not a problem. As long as the tag is in the concrete and logging temperatures, all of these things can be modified.

Here is a summary of the steps we will follow:

·       Set the pour time and location of this tag

·       Define a concrete type specific to this project and this concrete.

·       Add some notes to the tag, just for interest.

3.3.1 SETTING THE POUR TIME AND LOCATION

Select a tag (tap on its row) and then select the menu item Concrete Info on the Tag menu. The Concrete Info window pops up.

Tap on the text in the Location box, and enter a location for this tag.

Tap on the Write To Tag button. If it is labeled Save Data as in the above window then you haven’t connected to your i-CARD. Otherwise, the red LED on the tag should flash as the data is written to it. Then close this window by tapping on the OK button in the top right-hand corner.

3.3.2 DEFINING A CONCRETE TYPE

Now let’s add a concrete type for the tag which has just had its location set. In this case, we are going to use the standard 25 MPa concrete, without actually doing any cylinder compression tests. So the data that we have is that the concrete attains 25 MPa after 28 days at 20 degrees C. We also know that it attains 80% of its strength (20 MPa) after 7 days.

Select the menu item Concrete Types on the Project menu. The Concrete Types window pops up. Initially, it will look like this, with all of the fields blank, except the project name. This window assumes that you are using the TTF maturity method and that your project duration is set to Typical. If you have your Concrete Maturity Options set to EA, then your screen will look different, and you will be required to enter the results from your tests specifying the maturity of your concrete in Equivalent Age.

Double-tap on the first row of the Test Results list. An editor pops up. The TTF for the 7-day strength will be 5040 (7 days x 24 hours X 30 Degrees Celsius). The strength will be 20 MPa. Tap on OK.

Double-tap on the second row of the Test Results list. Once again, the editor pops up. The TTF for the 28-day strength will be 20160 (28 days X 24 hours X 30 Degrees Celsius). The strength will be 25 MPa. Tap on OK.

Now the "Fit Curve" button will be enabled. Tap on it, and HardTrack fits a curve to the test data, and then fills in the Strength Table.

Tap on the Save Type As button and save your strength table data to a file. In this case, the concrete type has been called Type25.

If you want to see a graph of your predicted strength, tap on the Graph button. These values can also be exported along with other concrete data once this concrete type is used by a tag.

 Setting the TTF or psi Target

It is very important that you set either a TTF or psi Target for your project.  HardTrack will recalculate the TTF-C & TTF-F in every area of the HardTrack solution if you set the Target.  If you do not set the Target, you will see unexpected results.

When your Concrete Pour Reaches the Target, the Tag will be highlighted on the main data grid where the Tags are displayed.  You will see this same highlighting on the Tag Status Form when the Target has been met.

You have the option to set a Maximum and Minimum Temperature for your Concrete Pour.  If you set these, HardTrack will warn you with Color on the main data-grid that displays the tags should the Concrete go above the Maximum or below the Minimum Temperature that you have set.

Now we can go back to the Concrete Info window and set the concrete type to the one we just created. Tap OK until we are back to the Project window. Once again, highlight the tag and select Concrete Info from the Tag menu. This time, the combo box from which you select the concrete type will contain the types “None” and “Type25”. Select “Type25” and tap on the Write To Tag button. The data will be stored in the tag and the internal data files. If your concrete is old enough, you will have a predicted strength value displayed.

When you return to the project window, it will also contain these same calculated values.  Every time you read your tags, these values will be recalculated. To see them in more detail, highlight the tag and select Status, Temp Log, Concrete Info, or Concrete Notes, all from the Tag menu. 

This section describes each type of data which HardTrack displays. The names match the labels that HardTrack displays. The list is sorted alphabetically.

Note that all calculations are based on the most recent data contained in the temperature log. If this data is old, then it is flagged in red, which is meant to suggest to you that it should be updated if possible. All data displays calculated using “old data” are also flagged in red.

4.1.1 ACTIVATION ENERGY

This is used by the Arrhenius Maturity Method and is encapsulated in the Q value. It is best thought of as the energy required to start a chemical reaction going. Most exothermic processes need energy to get started and the hydration of concrete is such a process. The concept is similar to standing a brick on its end. It takes a gentle push to get it past its initial stability, but once pushed far enough, the brick falls over, releasing more energy than was required to get it falling.

4.1.2AGE (OF THE CONCRETE)

The age of the concrete is calculated from the pour time to the timestamp of the last entry in the temperature log. The age does not take into account any time which may have passed since the tag was read: there is no data for it, and therefore no way to calculate the TTF and strength. A zero value will be displayed if a pour time has not been assigned to the concrete.

Ages are displayed in hours or days, depending on your display option setting, “Time Duration”.

4.1.3 ARRHENIUS MATURITY METHOD

The Arrhenius Maturity Method models the fact that the hydration of concrete is a chemical reaction that takes place at a rate determined by its activation energy and the current temperature. Arrhenius is applicable to a wider temperature range than TTF (Section 4.1.31) If testing has been done to determine the activation energy for the concrete type, then that value can be entered in the Maturity Methods options window, resulting in an even more accurate assessment of the concrete’s maturity.

Similar to TTF, it compares the maturity of the concrete to that of concrete matured at a constant 20 degrees Celsius.

4.1.4 A VERA GE TEMPERATURE

There are two average temperature values that may be displayed.

In the Temperature Log Window, the average temperature value for the entire temperature log is displayed. This probably includes times from before the concrete was poured.

In the Concrete Info Window, the average temperature value is only for the times since the concrete was poured, and therefore is a measure of the average temperature of the concrete itself.

4.1.5 BATTERY

This shows the current status of the battery, which may display differently for different tags. For example, i-Q8T tags will show battery voltage, whereas i-Q32T tags will show the percentage of battery power available.

4.1.6 CHRONOLOGICAL A GE

See Age (Section 4.1.1).

4.1.7 CONCRETE TYPE

Each batch of concrete is considered a different concrete type. Each concrete type should be tested and the results added to a specific concrete type. Then, the concrete associated with each tag can be assigned to one of the concrete types available for the current project.

The Concrete Type combo box provides a pop-down list of the concrete types available for the current project. It also includes “None”, in which case no concrete strength calculations will be done.

4.1.8 DATES

Dates are displayed using ISO 8601 Date format. This means that dates are displayed as “Year-Month-Day”. For example, August 19, 2004 is displayed as “2004-08-19”.

4.1.9 DATUM TEMPERATURE

This is used by the Time-Temperature Factor Method. This is your “base” temperature. The most common Datum Temperature is -10 degrees Celsius. This corresponds to curing the concrete at a 20 degrees Celsius.

4.1.10 EA

EA stands for Equivalent Age (See section 4.1 .11)

4.1.11 EQUIVALENT AGE (EA)

Equivalent Age is the maturity of the concrete as estimated using the Arrhenius Maturity Method (Section 4.1.3).

Concrete cured in the lab for 24 hours at its specified temperature (default 20 Degrees Centigrade) is considered to have an Equivalent Age of one day. Therefore, when your concrete attains an Equivalent Age of 5 days, it has the same maturity and strength as 5-day old laboratory cured concrete. Chronologically, it may take much more time (if it was cold) or much less time (if it was hot), but the strength of concrete with the same EA should always be the same.

There are limitations to Equivalent Age. Equivalent only addresses concrete maturity from a temperature viewpoint. Other factors such as inadequate moisture are not taken into account.

An Equivalent Age value will not be calculated if a pour time has not been assigned to the concrete.

Equivalent Age is displayed in days or hours, depending on your display option setting, “Time Duration”.

4.1.12 EXPEDITED PROJECT DURATION

See Project Duration (Section 4.1.24).

4.1.13 LAST CPU TO WRITE TO TAG

This is the serial number of the last handheld device to send a command to this tag. Since HardTrack is designed to work with multiple readers (multiple different handheld devices running HardTrack can download the data from the tags), some sort of audit trail is useful. In this way, you can identify the last person to change a tag’s setup.

Note that reading a tag does not affect this data. Only writing data to the tag will affect this value.

This is the time of the last successful download of the temperature log from a tag.

This time is displayed as Coordinated Universal Time (UTC) or local time, depending on your display option setting, “Time Zone”.

4.1.15 LOCATION

The location is a user-entered label that is used to help identify where the tag is. It could be the location of the tag in the concrete, or it could be a description of the concrete itself.

Since each tag has a location, you have the option of choosing how a tag is identified in the Project list: it can be displayed using its identifying code number or its location.

4.1.16 LOG BEGIN DATE

This is the time stamp for the first (oldest) temperature stored in the temperature log.

This time is displayed as Coordinated Universal Time (UTC) or local time, depending on your display option setting, “Time Zone”.

4.1.17LOGENDDATE

This is the time stamp for the last (most recent) temperature stored in the temperature log.  

4.1.18 LOG INTERVAL

The log interval is the time period between each temperature sample added to the temperature log. The default is 30 minutes. New tags may be shipped with this value set to 0. Initializing a tag or restarting logging will set this to the desired value.

A logging interval is always displayed in minutes.

4.1.19LOG SIZE, SIZE ON TAG

There are actually two temperature logs.

The first number is the size of the temperature log which has already been downloaded and merged with older temperature data. This temperature log, maintained on the Handheld device can grow to almost any size.

The second number is the size of the temperature log on the tag. An i-Q8T tag can store 1024 temperature values, while an i-Q32T can store 13,312 temperature values. When this value is exceeded, the temperature log wraps around and starts overwriting the oldest data values.

Usually, there is a lot of overlap between these two temperature logs. The amount of overlap depends on how frequently you download data from the tags. Only new data is added to the temperature log maintained on the Handheld device.

4.1.20 LOGGING

The temperature logging of a tag may be on or off. HardTrack does its best to make sure that a tag is always logging, but new tags may have been shipped without logging turned on. Initializing a tag or restarting logging will turn logging on.

4.1.21 MAXIMUM TEMPERATURE

There are two maximum temperature values that may be displayed.

In the Temperature Log Window, the maximum temperature value for the entire temperature log is displayed. This probably includes times from before the concrete was poured.

In the Concrete Info Window, the maximum temperature value is only for the times since the concrete was poured, and therefore is a measure of the maximum temperature that the concrete itself has reached.

Temperatures are displayed in degrees Centigrade or Fahrenheit, depending on your display option setting, “Temperature”.

4.1.22 MINIMUM TEMPERA TURE

There are two minimum temperature values that may be displayed.

In the Temperature Log Window, the minimum temperature value for the entire temperature log is displayed. This probably includes times from before the concrete was poured.

In the Concrete Info Window, the minimum temperature value is only for the times since the concrete was poured, and therefore is a measure of the minimum temperature that the concrete itself has reached.

Temperatures are displayed in degrees Centigrade or Fahrenheit, depending on your display option setting, “Temperature”.

4.1.23 MPA

See Strength of the Concrete (Section 4.1.30).

4.1.24 PROJECT DURATION

Projects can be set to have a duration of 28 days (typical) or 60 hours (expedited). This affects the way that HardTrack displays the strength tables and graphs. When the duration is set to typical, they are 28 days long and the units used are days (or TTF with steps of 720). When the duration is set to expedited, they are 60 hours long and the units used are hours (or TTF with steps of 30).

Whichever duration is selected, the user can fill in the strength table using either the Curve Fit or Interpolation capability.

4.1.25 PSI

See Strength of the Concrete (Section 4.1.30).

4.1.26 Q

This is used with the Arrhenius Maturity Method, and is the Activation Energy (in degrees K) divided by the Gas Constant (8.31 J/K-mol). The default value is 4700.

4.1.27 SENSITIVITY

The tags have two modes in which they operate: high or low sensitivity. This refers to how sensitive the tag is to the radio signals. There are some situations where it is better that the tags don’t “listen” too hard, but for HardTrack which expects to talk to tags buried in concrete, it is vital that the tags are set to high sensitivity. HardTrack does its best to ensure that this set correctly, but new tags are usually shipped with their sensitivity set to low. Initializing a tag sets its sensitivity to high. Do not bury a tag unless it is in high sensitivity.

4.1.28 SPECIFIED TEMPERA TURE

This is used by the Arrhenius Maturity Method. This is your “base” temperature. It is best if your Specified Temperature is close to your expected pour temperature.

4.1.29 STATUS

The status refers to whether or not HardTrack is connected to an i-CARD. It can be either “connected” or “NOT connected”.

When HardTrack is connected to an i-CARD, it expects to be able to communicate with tags. Buttons such as “Read Tag” and “Scan For Tags” are enabled. HardTrack also stores as much data as possible on the tags. This enables multiple data readers. You do not have to use the same Handheld device in order to download data from the tags.

When HardTrack is not connected to an i-CARD, then it works in a standalone mode. Buttons such as Read Tag and Scan For Tags are disabled. Other buttons which would normally write to the tag are also affected. For example, the Write To Tag button is relabeled to be the Save Data button. You are still able to modify things such as the pour time, but the data will only be stored and not written to the tags. HardTrack pops up warnings that the data will be out of sync with the tag data.

4.1.30 STRENGTH (OF THE CONCRETE)

The predicted strength is determined by looking up the TTF in the concrete strength table. An interpolation is done between the two closest data points. If there the Concrete Type for the tag is None, then this value will be displayed as zero. This value will also be zero if insufficient time has passed, or if the concrete has not been assigned a pour time.

Plowman’s equation could have been used to determine this value, but then you wouldn’t be able to edit the data values after performing the curve fit. You would also have been forced into always doing a curve fit to your data.

The strength of the concrete is displayed in MPa or psi, depending on your display option setting, “Pressure”.

4.1.31 TIME TEMPERATURE FACTOR (TTF)

The TTF of the concrete can be viewed as the area under the temperature graph of the concrete. The average temperature for each time interval in the log is calculated and multiplied by the length of the time interval. These are all summed together resulting in the TTF.

Concrete cured in the lab at 20 Degrees Centigrade gains 720 (30 degrees X 24 hours) units a day. The whole point of TTF is to be able to map your concrete to laboratory cured concrete. Therefore, when your concrete attains a TTF of 720 it has the same maturity as 1-day old laboratory cured concrete. Chronologically, it may take much more time (if it was cold) or much less time (if it was hot), but the strength of concrete with the same TTF should always be the same.

There are limitations to TTF. TTF only addresses concrete maturity from a temperature viewpoint. Other factors such as inadequate moisture are not taken into account.

TTF is applicable to the early life of concrete. TTF (and all other maturity methods) fails to address longer-term concrete strength aspects such as the “crossover” effect, which is the fact that concrete that is cured at a lower temperature during its early lifetime ends up stronger than concrete which was cured at high temperatures early on.

A TTF value will not be calculated if a pour time has not been assigned to the concrete. A TTF value is always displayed in units of Degrees Centigrade-Hours.

4.1.34 TYPICAL PROJECT DURATION

See Project Duration (Section 4.1.24).

5.0 GENERATING THE MATURITY-STRENGTH MAP

Tablet and Laptop users in effect are using HardTrack Desktop with a Bluetooth/USB Reader attached.  Please refer to this document for information and examples that will match the software that you are using on your tablet or laptop:

How to Set up Concrete Maturity with HardTrack

The following information is valid for all HardTrack Users.  However, all of the examples have been created for HardTrack Mobile users with a Handheld device.

The maturity-strength mapping is the key to estimating the strength of the concrete. For a given maturity (expressed in either TTF or EA), what is the strength?

One way of determining this mapping is to pay a laboratory to do the work. This is the recommended method if you require extremely accurate data. You can then manually enter the data into the Strength Table.

However, HardTrack is designed to generate maturity-strength mappings from compression tests that you do yourself. There is no need to cure the concrete under laboratory conditions because a tag attached to the test cylinder records an accurate temperature history for the cylinder. There is no need to break the cylinders at exact time intervals either: HardTrack will compensate for both the temperature and time interval.

5.1.1 PREPARING YOUR CYLINDERS

Pour your test cylinders as you normally would. Then either place a tag on top of the concrete, or attach it to the side of the cylinder. Then wrap it in insulation to make sure that the tag stays at the same temperature as the concrete. Do not bury the tag in the concrete because the size of the tag may create weak points in the cylinder.

5.1.2 PERFORMING THE COMPRESSION TESTS

Create a concrete type named appropriately. You will enter the results of your compression tests into this Concrete Type.

Break your cylinders at the appropriate times. For a typical project duration, ASTM C 1074 recommends breaking cylinders after 1, 3, 7, 14, and 28 days. For an expedited project duration, you will have to choose some appropriate intervals. An example breaking schedule could be:

·       6to12hours: every2 hours

·       12to36 hours: every4 hours

·       36to60 hours: every8 hours

HardTrack is flexible and will compensate for whenever you actually get around to

breaking them. The intervals do not have to be evenly spaced.

Before you crush the cylinder, remove the tag, download the temperature log and note down the maturity for the concrete. Then crush the cylinder. Load the concrete type and enter the result into the test results table. Make sure you enter both the maturity and the strength in the correct units. The labels at the top of the table indicate what units are expected. Depending on your settings, it may expect the maturity in TTF, EA in hours, or EA in days. It may expect the strength in MPa or psi.

5.1.3 FILLING IN THE STRENGTH TABLE

When you have a number of test results added to your concrete type, you should fill in the strength table. This contains the values that are actually used to map the concrete’s maturity to a strength. This mapping can be done as many times as you want. Feel free to re-fill in the strength table when you have added more test results. The new values will be applied to all tags which are set to that concrete type. Note that HardTrack will not predict a higher strength value than the maximum measured. If your last test was at 14 days, then the curve will “flat-line” for all days between 14 and 28.

HardTrack provides three ways to fill in the strength table:

·       Manual

·       Curve Fit

·       Interpolation

Each has advantages and disadvantages.

5.1.4 MANUAL

If you have had a lab develop your maturity-strength relationship, then you can enter these values manually. It will be tedious because you have to enter 60 hourly values, and then 28 daily values. You can also use this method if HardTrack failed to fill in the data in a way that satisfied you.

The most likely scenario for using the manual method is to first use one of the automatic methods (curve fit or interpolation) and then modify some of the values.

5.1.5 FITTING AN EXPONENTIAL CURVE

Concrete is meant to gain strength at an exponential rate. This means that it should be possible to fit an exponential curve to your test results. The Fit Curve button does exactly this. Since your data is unlikely to be a perfect fit, HardTrack does a best-fit approximation, trying to produce a curve that goes as close to your data points as possible.

5.1.6 INTERPOLATING BETWEEN YOUR DATA POINTS

Rather than fit a curve to your data, you might want to interpolate between the data points instead. The Interpolate buttons does this, essentially by “connecting the dots”. In order for this to produce a nice, smooth graph, you will need to have a fair number of test results. However, this has several significant advantages over the curve-fitting method:

·       The strength data matches your test results exactly

·       The strength data can have extra curves and discontinuities. Although it may not match the way concrete gains strength, in theory, it does match the way YOUR concrete gained strength as tested. This is especially true when you are looking at very early age concrete, where the strength gain doesn’t necessarily line up nicely with the 28-day strength gain.

5.1.7 CURVE FITTING VS INTERPOLATION

The following examples illustrate the differences between curve fitting and interpolation.

Curve Fit on left, Interpolation on right
28 Day on top, 60 hour on bottom

In this case, the Curve Fit (on the left-hand side) is a far better choice than the Interpolation. The input data falls nicely onto the exponential curve. This holds true for both the 28 Day view (typical project duration) and the 60 Hour view (expedited project duration).

Curve Fit on left, Interpolation on right
28 Day on top, 60 hour on bottom

In this case, for a 28-day duration, either method could be selected (although the graph doesn’t show it, the interpolated data points do pass through all the test results data). However, when the 60-hour duration is viewed, it is obvious that we want to use the interpolation because it tracks the strength gain much better.

Almost all the data that HardTrack stores in its data files can be exported to either Comma Separated Value (CSV) files or straight text files. A CSV file can be loaded into Excel on a PC, while text files are intended to be loaded into NotePad or WordPad right on the Handheld device. In general, CSV files are used when further analysis of the data is going to be done, using Excel, while text files are used to view and print the data.

There are two sets of data that can be exported: temperature logs and concrete info.

6.1.1 TEMPERATURE LOG EXPORTS

Temperature logs are concerned solely with the temperature log as recorded by the tag and are independent of the concrete information. You can choose whether you want the entire temperature log, or only the time logs after the concrete was poured.

The units used for export will match your current display options.

6.1.2 CONCRETE INFO EXPORTS

Concrete Info can also be exported. This is a more complete export, but is biased towards the state of the concrete. As such, any data from before the pour time is not included. The exported data includes:

·       A concrete summary

·       A detailed log of temperature, age, TTF/EA, and strength

·       A table of the compression test results along with the calculated Plowman’s equation.

·       A table of the predicted concrete strengths for a given age or TTF. This is extracted from the concrete type assigned to the selected tag. Both the 60 hour and 28-day tables will be exported.

Again, the units used for export will match your current display options. 

6.1.3 All Tag’s Temperature Logs with Graphs, in a Single Report

After opening a Project, Click on Project, Export, Project Temperature Reports to Excel:

Then Click on Excel Export:

The Excel File will contain tab for each of your Tags/Sensors:

6.1.4 All Tag’s Concrete Info (Maturity) with Graphs, in a Single Report

After opening a Project, Click on Project, Export, Project Maturity Reports to Excel:

This section describes the functions and capabilities available to you. It is organized by the menus and windows that HardTrack presents to you.

7.1 MENUS

The menus are only available when the Project Window is displayed. 

7.1.1 PROJECT MENU

The Project menu allows you to manage projects. A project groups together a set of tags that are associated with a particular project, such as a bridge. The tags in a project also share the same set of concrete types.

The New menu item closes the current project, removes all tags from the list, and switches us back to the “untitled” project. Tags can be added to this new project by tapping Add Known Tag or Scan For Tags. The project becomes named after it has been saved.

The Save menu item flushes all the data to data files. This flushes both the project file and the tag data files. Normally, this happens automatically when the program is exited, but this provides an extra measure of security.

The Save As menu item pops up a file selector and you are expected to enter a new name for the project. When OK is tapped, a new project file is created, containing the tags in the current list. If you enter an existing filename, then overwrite confirmation is requested.

The Concrete Types menu item pops up the Concrete Types Window. The Concrete Types Window is used to create concrete strength tables by entering the results of cylinder compression tests.

The Delete menu item deletes a project and all of the concrete types associated with it. The tag data files and temperature logs are not affected.

The Exit menu item exits the software. All of the data for the current project is saved.

The Tag menu provides access to the tag-specific capabilities of HardTrack.

The Read Tag menu item queries the tag for all of its data. The temperature log is downloaded from the tag and merged with any pre-existing data. All data displays are updated.

The Status menu item pops up the Status Window, which provides a summary of the selected tag’s status. The Status Window is also the best place to read the tag from since it provides a “Ping” command, which enables you to find the optimum place and orientation for reliable communications with the tag.

The Temp Log menu item pops up the Temperature Window, which provides a summary of the temperature log for the selected tag. The Temperature Window also provides access to the graphing and exporting of temperature logs.

The Concrete Info menu item pops up the Concrete Info Window. The Concrete Info Window is used to define the concrete associated with the tag: its location, its pour time and its Concrete Type.

The Initialize Tag menu item is used to ensure that the selected tag is ready to perform as a concrete monitoring tag. The tag is set to High Sensitivity and commanded to start logging temperatures.

The Delete Tag menu item removes the selected tag from the current project. The tag data files and temperature logs are not affected.

The Scan For Tags menu item broadcasts a request for all tags within range to respond. The tags which respond are added to the current project. Note that this does not clear the project first. If you are in an “untitled project”, then all the tags found will be added. If not, you will have to confirm the addition of each and every new tag to the current project.

The Add Known Tags menu item is used to add tags that have already been located (i.e. have been scanned or been in a project previously) to the current project. Tags may belong to multiple projects.

The Options menu provides access to the various configurations that are possible with HardTrack.

The About HardTrack menu item pops up a window displaying the current version of the software.

The Display menu item pops up the Display Options Window. This window allows you to select the units used for the display and export of data.

The i-CARD menu item pops up the i-CARD Options Window. This window allows you to connect or disconnect from the i-CARD, and to control its communications range.

The Maturity Method menu item pops up in the Maturity Method Window. This window allows you to select and configure the maturity method used. Both Time Temperature Factor and Equivalent Age (Arrhenius) methods are supported.

The Project Duration menu item pops up the Project Duration Window. This window allows you to select either a 28 day or 60 hours project duration.

Windows are used to group related functions and data displays. Once you understand the basic groupings, this enables you to quickly view and access related data and capabilities. Project-specific windows operate on things associated with the current project. Tag-specific windows operate on things associated only with the currently selected tag. Normally you select a tag, and then pop up the desired window using the menu. Once within the tag-specific windows, you can switch back and forth between them using the tabs.

The project-specific windows are:

·       Project Window.

·       Concrete Types Window.

·       Concrete Types Graph Window.

The tag-specific windows are:

·       Status Window.

·       Temperature Window.

·       Temperature Graph Window.

·       Temperature Export Window.

·       Concrete Info Window.

·       Concrete Info Export Window.

·       Notes Window.

Other windows:

·       Display Options Window.

·       i-CARD Options Window.

·       Maturity Method Window.

·       Project Duration Window.

The Project window displays the list of tags in the current project. The name of the project is displayed in the title bar.

Each row in the list contains:

·         The tag id (or location)

·         The chronological age of the concrete (time elapsed since the concrete was poured)

·         The Time Temperature Factor (TTF) in degree Centigrade Hours or Equivalent Age (EA) in days or hours.

·         The estimated strength of the concrete in MPa or psi.

This is HardTrack’s main window and allows access to the menus. The menus allow you to manage projects, view and command tags, and set user options. The color red is used to alert you to the presence of old data. One of the display options allows you to specify how old data has to be before it is considered out of date.

A single tap on a row selects a tag. Once a tag is selected, you can use the menus to go to the desired tag specific window or to start an operation.

A double-tap on a row selects the tag and pops up the Status window.

7.2.2 CONCRETE TYPES WINDOW

The Concrete Types window allows you to enter the results of concrete cylinder compression tests, which are then curve-fitted to a predicted strength for this particular concrete. This predicted strength is then used to calculate the concrete’s strength for any TTF (or EA). The appearance of this window changes depending on the current maturity method and project duration.

Concrete Types Windows: TTF with a 28-day duration, EA with a 60-hour duration

The two tables are the core of this window. The first is the Test Results list which contains the results of your cylinder compression tests for this batch of concrete. Each row contains the TTF (or EA) of the test and the strength that was measured. The user enters both the TTF (or EA) of the test and the concrete strength measured. You can enter your data in any order.

The second is the Strength Table list. This contains the predicted strength for this batch of concrete for each of the first 28 days (or 60 hours), listed by its TTF (or EA). Although the data in this table can be manually entered, the expected usage is to have it generated automatically from the Test Results data. If you have special requirements, you can change the values in this table manually after the curve fitting, or even fill in all of the data values manually instead. If you opt to do the whole thing manually, then you have to do switch between project durations to fill in both the 60-hour table and the 28-day table.

The Load Type button loads a concrete type. Note that only concrete types for the current project are available, and any concrete types saved will also be only for the current project.

The Save Type button saves a concrete type and all of its associated data to a file. Any changes to a concrete type, including filling in the strength table are not saved unless this button is pressed. Once again, note that the concrete type will be specific to the current project and not available to any other projects.

The Fit Curve button is enabled when there are sufficient test results completed in the Test Results list. When this button is tapped, HardTrack fits an exponential curve to the data and then fills in the Strength Table with data calculated using the formula for the fitted curve. The formula used was put forward by Plowman.

For a more detailed description, see Section 5.1.3.

The Interpolate button is enabled there are sufficient test results completed in the Test Results list. When this button is tapped, HardTrack produces a strength table that looks like all the data points have been connected with straight lines. This is done by interpolating between the closest two test results for each required data point. This provides an exact match to the test results and allows the use of data that does not follow an exponential curve.

For a more detailed description, see Section 5.1.3.

The Graph button pops up the Concrete Type Graph window. This provides a graphical view of how the concrete gains strength over the first 28 days.

Test results are entered by double-tapping on one of the rows, which pops up a simple editor. Highlight the text you want to change and enter your results. The Soft Input Panel (SIP) is automatically popped up when you tap on the text boxes. The type of SIP that pops up depends on user preferences. In this case, the “Letter Recognizer” is used.

The units expected are displayed across the top of each text box. Make sure you use the correct units. Depending on your settings, it may expect the maturity in TTF, EA in hours or EA in days. It may also expect the strength in MPa or psi.

The same method is used to edit the Strength Table. When editing the Strength Table, the Maturity Field is not editable.

The Concrete Graph window shows you your current strength table as a graph. The time scale displayed depends on the current project duration.

A 28-Day graph and a 60-hour graph of the same strength table

The red line graphs the strength table data, while the blue peaks are the test results data from which the strength table was generated.

Tap on “OK” to return to the previous window.

The Status window summarizes the status of a tag. The tabs allow quick access to the other tag-specific windows.

The Ping button and Ping Status display make this the best window for communicating with the tag. While HardTrack is pinging a tab, the other functions of this window are not available.

The Ping button is used to help find tags and the best location to read them from. Tap on the Ping button and HardTrack starts sending queries to the tag. When tag responds, HardTrack beeps, and the Ping Status bar is increased. Each time a tag fails to respond, the Ping Status bar is decreased. While HardTrack is pinging a tag, you move the Mobile Device around, trying to find the optimum location for tag communications. Once you have found the optimum location, the tap on the Stop Ping button.

The Restart Logging button restarts the logging at the desired interval. If you do not select the default value, then HardTrack warns you that you are not following the recommended settings, but allows you to continue (the default logging interval is set in the Project Duration window). It also attempts to download the temperature log from the tag first, because restarting the logging on a tag clears the temperature log on the tag.

Once logging has been restarted, then HardTrack also switches the tag into High Sensitivity, just to make sure that it will still work when buried in concrete.

If the tag timer has been calibrated, then that value will be automatically applied when the log is restarted.

The Read Tag button downloads all of the data from the tag, including the complete temperature log. The text data from the tag (concrete pour time, tag location etc.) overwrites the older data residing in the Handheld device       . The temperature log data is merged with the existing temperature log. If you are not connected to the i-CARD, this button is disabled.

7.2.6 TEMPERATURE WINDOW

The Temperature window provides a detailed view of the temperature log of the currently selected tag. The tabs allow quick access to the other tag specific windows.

The Graph button pops up the Temperature Graph window. The Temperature Graph window displays the contents of a temperature log as a line graph.

The buttons at the bottom of the scrolling temperature log display are used to move to different portions of the temperature log:

·       The First button jumps to the start of the temperature log. This is the oldest

data in the temperature log, and is usually from before the concrete was poured.

·       The Prev button steps back one page worth of data. A page contains 256

entries.

·       The Next button steps forward one page worth of data.

·       The Last button jumps to the end of the temperature log. This is the most recent data in the temperature log.

The Read Tag button downloads all of the data from the tag, including the complete temperature log. If you are not connected to the i-CARD, this button is disabled.

The Temperature Graph window provides a picture of the temperature log, 48 logging intervals at a time. Since logging normally takes place every 30 minutes, each displayed graph usually spans 24 hours.

The Date displayed at the top of the window is for the first data point (the left-most one) displayed on the graph. This is affected by the display options (can be either local time or UTC).

The Range displayed at the bottom of the graph summarizes the time period covered by the graph. This is usually 24 hours at the standard 30-minute logging interval.

The buttons at the bottom of the graph are used to move to different portions of the temperature log:

·       The First button jumps to the start of the temperature log. This is the oldest

data in the temperature log, and is usually from before the concrete was poured.

·       The Prev button steps back one screen worth of data. This is usually 24 hours

at the standard 30-minute logging interval.

·       The Pour Time button jumps to the time at which the concrete was poured.

·       The Next button steps forward one screen worth of data. This is usually 24 hours at the standard 30-minute logging interval.

·       The Last button jumps to the end of the temperature log. This is the most recent data in the temperature log.

7.2.8 TEMPERATURE EXPORT WINDOW

The Temperature Export window is used to export the temperature log for the selected tag to either a Comma Separated Value (CSV) file or a straight text file. The CSV file can then be imported into Excel on a PC, while the text file can be viewed and edited in Pocket Word right on the Handheld device.

There is an option to select the entire temperature log, but the most common choice would be to select only the times since the concrete was poured.

Since the exported file will use your current display options, they are shown in this window.

Tapping the CSV Export button pops up a file selector, which is used to specify a filename for the exported CSV file. This file will be placed in the “My Documents” folder, with a “.csv” extension.

7.2.9 CONCRETE INFO WINDOW

The Concrete Info window is where you enter information about the concrete. HardTrack calculates the current age, TTF and strength of the concrete. The tabs allow quick access to the other tag-specific windows.

The Location is where you specify where the tag is located. This can be either a description of the concrete or the location of the tag within the concrete, whichever is most useful for you.

The Concrete Type is also where the concrete is matched to a specific concrete type so that its strength can be determined. You select the appropriate Concrete Type from the pop-down list. The list contains only the concrete types which you have created for this project. If you haven’t created any, the only option will be None.

In order to calculate the age, TTF (or EA) and strength of the concrete, HardTrack needs to know when the concrete was poured. You are welcome to enter this ahead of time, as it is easy to modify later, after the fact, if the concrete was not poured when expected.

The Pour Time is changed by highlighting the value to change, and then tapping the up/down arrows.

The Pour Date is changed by tapping on the arrow beside the date. A calendar is popped up. Just tap on the date you want to set it to. Frequently the first thing you want to tap on is the “Today” text, which jumps you to the current date, and then you can then move forwards or backward as desired.

Once these values have been changed, they need to be written to the tag. Tap on the Write To Tag button. If you have a Save Data button instead, then you are not connected to your i-CARD. You can still save the data, however.

When this is done, HardTrack will update the displayed Chronological Age, TTF (or EA) and strength of the concrete.

The Read Tag button downloads all of the data from the tag, including the complete temperature log. All of the displayed data fields are recalculated and redisplayed. If you are not connected to the i-CARD, this button is disabled.

7.2.10 CONCRETE INFO EXPORT WINDOW

The Concrete Info Export window stores all of the information about the concrete to either a Comma Separated Value file or a straight text file. The CSV file can then be imported into Excel on a PC, while the text file can be viewed and edited in Pocket Word right on the Handheld device.

Since the exported file will use your current display options, they are shown in this window. A brief summary of the concrete’s current state is also shown.

There are several Export Options. These checkboxes determine whether or not the specified data will be exported to the file. They are:

·       Detailed TTF and Strength Data Checking this box selects the complete data log, sorted by timestamp, of the concrete’s chronological age, TTF, and strength.

·       Compression Test Results Checking this box selects the compression test results and the values calculated for Plowman’s equation.

·       Predicted Strength Data Checking this box selects the predicted strength table which contains the age, the TTF, and a strength value.

 Tapping the CSV Export button pops up a file separator, which is used to specify a filename for the exported CSV file.  This file will be placed in the "My Documents" folder, with a ".txt" extension.

Here is an exported text file, loaded into WordPad:

The file is more readable if you set the zoom to 75% and turn off the Wrap to Window option.

The Concrete Notes window allows a user to add custom notes to a tag which can aid you in recording events and information regarding this particular tag or concrete. The tabs allow quick access to the other tag specific windows.

When you start editing the text in the window, the Soft Input Panel (SIP) is popped up. The type of SIP that pops up depends on user preferences. In this case, the “Keyboard” SIP is being displayed

The Save Data button becomes the Write Tag button when connected to the i-CARD. Note that in this case, since we are not connected to an i-CARD, the button is labeled Save Data and that the Read Tag button is disabled.

The Read Tag button downloads all of the data from the tag again. This is a good way to confirm that everything has been written correctly to the tag. The note is redisplayed, based on what was just read from the tag. If you are not connected to the i-CARD, this button is disabled.

HardTrack can be modified to match the preferences of different users. There is a Display Options window, an I-CARD Options window, a Maturity Method window and a Project Duration window..

7.3.1 DISPLAY OPTIONS WINDOW

The Display Options window allows you to select which units the data is displayed in. This only affects the display and export of data. Internally, the data values are always stored the same way.

The Time Zone option determines how times and dates are displayed. Internally, times are always stored in Coordinated Universal Time (UTC) format. For user convenience, the display of times can be changed to Local Time, which is determined by the Handheld device settings.

The Temperature option determines how temperatures are displayed. Internally, temperatures are always stored as degrees Celsius (deg. C). For user convenience, the display of temperatures can be changed to degrees Fahrenheit (deg. F).

The Time Duration option determines how the chronological age of the concrete is displayed. Time duration can be displayed in either hours or days.

The Old Data option determines when HardTrack flags displayed data as being out of date. This makes sure that you are aware of when new data should be downloaded from the tags.

The Tag Display option determines how tags are identified when display space is limited. They can be labeled with either their Tag Id or the location of the tag, as entered by the user.

7.3.2 I-CARD OPTIONS WINDOW

The i-CARD Options window allows you to connect and disconnect from the i-CARD, as well as to control the communications range.

When the i-CARD is connected, the Connect button changes to a Disconnect button, and vice-versa. When you are working in a situation where you can’t or don’t want to communicate with tags, then you could disconnect from the i-CARD. Buttons that try to read from the tags will become disabled, while buttons that attempt to write to tags are either disabled or changed to buttons that only save data and do not attempt to write it to the tag.

When selected, the Autoconnect check box causes HardTrack to connect to the i-CARD each time the program is started.

HardTrack works with different kinds of i-CARDs. By far the most convenient and common is the CF i-CARD, but a Serial i-CARD will work with a PC as well.

When communicating with tags that are buried in concrete, your Communications Range should always be set to maximum. However, if you are working with tags that are not hidden or buried and are very close, then you might want to decrease your communications range.

The Maturity Method Options window allows you to select the maturity method to use. It also allows you to set some of the parameters for each maturity method.

In more recent years, HardTrack users have used a Datum Temperature of 0 degrees Celsius as the default value.

The Project Duration Options window allows you to set your projects to be of typical or expedited duration. This only affects the way that the Concrete Types and Concrete Graph windows display the data. Internally, concrete strengths are always calculated the same way.

A typical project has a duration of 28 days. The Concrete Types window will display the Strength table as a list with entries for Day 1 to Day 28. The actual maturity values in the list will be determined by your current maturity method and display settings. They could be TTF, EA in hours, or EA in days. The Concrete Graph window will display a 28-day graph.

An expedited project has a duration of 60 hours. The Concrete Types window will display the Strength table as a list with entries for Hour 1 to Hour 60. The actual maturity values in the list will be determined by your current maturity method and display settings. They could be TTF, EA in hours, or EA in days. The Concrete Graph window will display a 28-day graph.

8.1 TAG INSTALLATION

Initialize up your tags, before they are buried. If you know the expected location and pour time, fill these in as well. Communications with the tags become less reliable once they are in the concrete, and it is nice to be relaxed rather than panicked when you are surprised by the appearance of the cement truck. Besides, sometimes you just can’t get to the tags when they are in the middle of a large pool of wet concrete.

Attach the tags securely. Don’t let them get washed away by the flood of concrete. Alternatively, you can dig a little hole in the concrete before it starts to set and place your tag into it.

Tag orientation can really help. Place the tag so that the red LED points towards the location that you expect to read the tag from.

Do not bury standard tags deeper than 8 inches from the surface that you are going to read them from. It may be hard or even impossible to communicate with the tags if they are deeper than this.

If you need to bury a tag deeper than 8 inches, then use one of the external antenna tags and snake the end of the antenna up so that it is just under the surface from where you want to read it from.

If you want to read data from a tag while traffic is passing over it, then use one of the external antenna tags and run the antenna over to the edge of the lane/bridge so that it is just under the surface from where you want to read it from.

8.2 READING TAGS

Distance from the concrete makes a big difference.

Orientation to the surface makes a big difference. We have found that holding your device directly above the tags (perpendicular to the surface) really helps.

Antenna orientation makes a difference. If you are standing on the concrete above the tag, holding the antenna horizontal works best. Turning 90 degrees (i.e. if you were facing west, turn and face north) may also help. You can also turn that antenna so that it is vertical or horizontal. The Ping command on the Tag Status window is a great help in locating the best place to read a tag from.

If there is lots of rebar in the concrete, move about a bit. You need to have a direct line of “sight” to the tag, and if the tag is “hidden” behind some rebar it will be difficult to read. Again, the Ping command should be used to locate the optimum place to read the tag from.

Concrete changes over time, and this affects the communication with the tags. Surprisingly, communication with the tags is okay when the concrete is 1 to 2 hours old, then it degrades a bit as the concrete hardens. Then as the concrete hydrates, even more, communications with the tags improve once again.

8.3 EXTERNAL ANTENNA TAGS (I-Q8TE OR I-Q32TE) External antenna tags require a bit more care than standard tags.

Initialization is a bit more difficult because an uninitialized tag is likely to be in low sensitivity and the external antennas are not as efficient as the internal ones: they really need to be in high sensitivity mode. Therefore, the Handheld device should be a few feet from the end of the antenna to initialize it. Once the initialization has been done, then it will be much easier to communicate with.

The antenna should be securely attached to the tag. For best performance, the antenna should be set up to that its tip will be within a few inches of the surface of the concrete, preferably running parallel to the surface.

External antenna tags are more orientation-dependent then the standard tags, so reading the tag may require a different position or location as compared to a standard tag.

Note: External Antenna Tags (i-Q8TE or i-Q32TE) are no longer Available

HardTrack can be tweaked to your specific needs. Some of these features need to be used with care.

8.4.1 RESTARTING LOGGING

The default for temperature logging is to record a temperature every 30 minutes or 5 minutes for expedited projects. However, there may be unusual situations where different intervals are needed. HardTrack will allow you to specify your own logging interval, as well as a time and date when the logging should start. The use of this capability may mean that HardTrack will be unable to accurately assess the maturity of your concrete.

WARNING: Do NOT use this feature on a tag that has never been initialized. Doing so may put the tag into a state where it appears to be working normally, but tag data will be inaccessible. So make sure the tag has been initialized at least once before using this feature. To protect users from accidentally doing something that could interfere with HardTrack’s capabilities, the use of this feature is protected by warning messages… lots of them!

This is also the way to reset the temperature log on the tag. HardTrack will download the latest temperature log from the tag and then restart the logging at the default rate. This decreases the size of the temperature log to be downloaded from the tag, but the long-term temperature log maintained by HardTrack will contain all the data gathered so far.

8.4.2 EDITING THE CONCRETE TYPES DATA

Sometimes you may not be happy with the way that Concrete Monitor has fitted a curve to your test results. Your test results are unlikely to be perfect, and it is likely that it is not possible to fit an exponential curve to them to your satisfaction.

8.4.3 FILES

HardTrack stores all of its files in the “My Documents/Concrete Monitor” folder. The only exception to this rule is that exported files are stored directly in the ”My Documents” folder. This makes them easy to locate.

Please do not remove, rename or delete any of the files in the ”My Documents/Concrete Monitor” folder. Do feel free to back them up onto your PC if you want.

HardTrack is able to recover from the loss of these files for the most part. But the long-term temperature logs will be gone forever. Assuming you can go out and scan for the tags again, you will still be able to recover all the data that is stored in the tag. This is everything, except the long-term temperature logs and the concrete types files. The short-term data (the last 1024 entries in the log) will be read from the tag again and be restored. You should be able to re-create the concrete type's data files from your test results data.

8.4.4 CRASH RECOVERY

The Handheld is pretty stable and lockups and crashes are, fortunately, quite rare. However, it is best to be prepared because a Handheld keeps all or its data in volatile RAM. This means that you could lose all your data even in something as commonplace as battery failure.

Make backups of the “My Documents/Concrete Monitor” folder. Even if you haven’t done so, the copy that Active Sync maintains on your desktop PC will probably be enough.

If your Handheld does lockup on you, try the following steps to recover:

·       Push the reset button with the stylus. The reset button is located on the base, near the right-hand side.

·       When your Handheld restarts, it may come up with all your programs and data intact. In this case, you are done. However, if it displays the system setup screen (asks you to tap on crosses on the screen to configure the display) then

you have probably lost everything, and must re-install. This is a hassle, but if your data is on your PC, it will only take 5 minutes.

·         Complete the setup as prompted. Set up your user information if you desire to do so.

·         Remove your i-CARD.

·         Place Handheld into its cradle. When Active Sync connects, you may be able to specify the same name for your Handheld device as before. If not, then let it create a new folder and copy everything from your old one into the new one. In either case, Active Sync should restore all of the files that were in your “My Documents” folder.

·         Reinstall the i-CARD drivers (see Installation)

·         Reinstall the HardTrack software (see Installation).

·         Startup HardTrack again and confirm that all your data is there. You may have to go back to the site and re-read the last set of data from the tags.

9.1I CAN’T GET ACTIVESYNC TO INSTALL ON MY PC?

Compaq ships the Handheld with 2 CDs. Unfortunately, the only one that anyone ever notices is the one that isn’t needed with the Handheld! Ignore the CD titled “Handheld device (ROM Upgrade)”. The one you want is hidden behind its own labels. Until you open it, the only label you see is the Microsoft Certificate of Authenticity for Microsoft Outlook Version 2002. Open it up, and you will see that the CD includes ActiveSync 3.X. Install ActiveSync from this CD or feel free to download a newer version from Microsoft.

9.2I WANT TO BURY A TAG IN 3 FEET OF CONCRETE. WILL IT WORK?

9.3 WHY ONLY 28 DAYS FOR CONCRETE TYPES DATA?

Most of the interest in concrete maturity is targeted at the strengths gained in the first 28-days. And the equation used, Plowman’s is really only applicable to this time period.

9.4 WHY DON’T YOU PROVIDE ANY DEFAULT CONCRETE TYPES DATA FILES?

There are situations where it would be adequate to use some standard data values for your concrete batch. For example, projects where the maturity of the concrete is being monitored for interest only, such as in a simple slab poured in freezing temperatures. The maturity results obtained would be accurate as long as the batch of concrete matches its specification. Just because you trust your supplier doesn’t mean that your DOT does!

9.5 HOW DO I ENTER MY OWN ARRHENIUS ACTIVATION ENERGY?

Using Arrhenius may make some windows a little slower to pop up, especially if you have a lot of data. This is even more obvious during an export which includes detailed maturity information because HardTrack calculates a value for each and every data point in the temperature log.

9.6I CREATED A NEW PROJECT AND NOW MY CONCRETE TYPES HAVE DISAPPEARED?

Concrete types are associated with a project. This is to ensure that each and every project has its own set of concrete types. These are intended to be batch-specific and based on the actual compression test results for that batch.

Once you switch to a different project, you will have to create concrete types for that project. Although tags can be shared across projects (for example, projects and sub-projects are quite possible), the concrete types that they are associated with cannot. You will need to create a duplicate concrete type for each project

containing the same data.

9.7I JUST RESTARTED LOGGING ON MY TAG, AND NOW I CAN’T READ THE TEMPERATURE LOG?

Each time a tag is commanded to start logging temperatures, it first clears the current temperature log and then starts logging at the specified logging interval. Since the temperature log is empty, there is no temperature log to download until the time period passes (usually 30 minutes) and the first measurement is added to it. This means that any subsequent reads will FAIL until data has been added to the log. Do not panic, this is just the way that it works.

You don’t have to worry about losing recent temperature log data when restarting the logging. HardTrack downloads the temperature log before restarting the temperature logging to make sure that this data isn’t lost.

9.8I JUST INITIALIZED MY TAG AND NOW I CAN’T READ THE TEMPERATURE LOG?

Initializing a tag also restarts the temperature logging. Refer to the Restarted Logging question.

9.9ALL MY “READ TAG” BUTTONS ARE GRAYED OUT?

You probably aren’t connected to your i-CARD. If you have tried to connect several times and it has been unable to do so, eject the card and re-insert it. Failing that, eject your Handheld from the expansion adapter and plug it back in. You should hear the “whoosh-click” insertion sound.

9.10 I READ MY TAGS WITH A DIFFERENT COMPUTER AND IT SHOWS A DIFFERENT TEMPERATURE LOG?

The time stamps assigned to tags are based on the clock of the host computer. It sounds like one of the clocks of your two computers is not correct. Make sure that your computer’s clock is correct any time you are going to communicate with tags.

The temperature log graphs are a simple display of the temperature from each log sample, and the log samples may be done at different rates. The graph does not attempt to compensate for the different logging intervals, just displays 48 data points from the log. If you are displaying a graph for which the first 24 data points were taken at 30-minute intervals, while the last 24 were done at 5-minute intervals, the range would be about 14 hours. The first half of the graph would display the temperatures for the first 12 hours, and the second half of the graph would display the temperatures for the last 2 hours.

9.12 CAN I STILL USE PULL-OUTS?

Although several studies claim that pull-outs are unnecessary and substantially less accurate than the maturity method, there is a clever way to use them in conjunction with the maturity method. Since HardTrack provides you with a predicted strength for the concrete, you can use the pull-outs in a non-destructive manner, by only applying a pull-out force that will not exceed that strength of the concrete. In this manner, you can be assured that the concrete has attained the minimum strength required. This way the pull-out can be re-tested at a later date as well.

9.13 I PUT MY HANDHELD IN A CLOSET FOR 2 MONTHS AND IT WON’T RECOGNIZE THE I CARD ANYMORE?

The Handheld never really turns off, so its batteries will die after a few months of inactivity. If the batteries get really low, the Handheld will lose the contents of its memory.  All you have to do is recharge the batteries.  The Handheld will automatically reinstall the software when it is started and recover any saved projects & concrete types for you.

9.14 I AM HAVING A HARD TIME INITIALIZING AND CALIBRATING MY TAGS?

In addition, you should be aware of the following things which can affect your communications with the tag:

·       Avoid areas with lots of RF interference. For example, avoid communicating with the tags near cordless phones (especially 900 MHz) and wireless network routers.

·       Be aware that RF reflections and dead zones exist. Frequently moving the tag from the middle of a tabletop to the edge will help. Consider moving to a different room if you continue to have problems.

·       Being too close to a tag is as bad as being too far away. They can easily get “flooded” when in high sensitivity mode.

·       Interrogate your tags separately. Sometimes the tags seem to interfere with each other when they are all jumbled in a box. It often helps to pick one tag and initialize it well away from the others.

·       Try different orientations of both the tag and the Handheld.

·       Don’t forget to check the power level on the i-CARD. If you have that set low, communicating through concrete may be impossible. If you have it set high, being too close to the tag may overpower the signal.

9.15 HOW DO I STOP A TAG FROM LOGGING?

You can’t stop the tag from logging. You can restart the logging at any time by pressing the Stop Logging button on the Tag Status Form, which does not clear the temperature log contained in the tag itself.

9.16 WHY DOES IT FLASH INVALID KEY FILE AT ME?

If everything has been working fine, then something has corrupted or deleted your key.txt file. This file has to be in “My Documents/Concrete Monitor” and must contain the code for your i-CARD. If you know what the code is, then you can use Notepad on your desktop machine to create a new “key.txt” file, then copy it to the right location on your Handheld. If not, then you must contact WAKE to get a new key.

9.17 I KEEP GETTING A “FAILED TO READ TEXT DATA” MESSAGE?

Make sure that you initialized your tags. This fills in a default structure on the tags themselves. If HardTrack does not find this structure on the tag, it assumes that it isn’t meant to use the data on the tag.  If this is an intermittent thing, then you need to position yourself a little better with regards to the tag. Try different antenna orientations, getting closer or farther from the tag.