Recording Nuclear Gauge Calibration Equation Values to AS 1289.5.8.4 and WA 135.1 (Method 1)

Applies to QESTLab

This article describes how to record nuclear density gauge calibration equations and valid ranges obtained by AS 1289.5.8.4 or WA 135.1 for use on AS 1289.5.8.1 or WA 324.2 field density tests.

Overview

Nuclear field density testing in some regions of Australia requires a wet density to be calculated from a calibration equation according to AS 1289.5.8.4 or WA 135.1. The Calibration Equations from Standard Density Blocks (AS 1289.5.8.4, WA 135.1 Method 1) worksheet in QEST Platform allows entering the calibration equation constants defined in AS 1289.5.8.4 and WA 135.1 (Method 1). The worksheet does not support the full nuclear gauge calibration and is intended to be used with a certificate from a calibrating agency containing the equation constants along with the minimum and maximum valid count ratios.

QEST Platform supports calibration equations for field density of the form:

Wet Density = slope x ln(Density Ratio) + intercept

A calibration equation for the gauge is determined for each test depth.

Calibration Equations from Standard Density Blocks Worksheet

The calibration Worksheet named Calibration Equations from Standard Density Blocks (AS 1289.5.8.4, WA 135.1 Method 1) is for recording the constants established for the equations according to AS 1289.5.8.4 or WA 135.1 Method 1 only. As mentioned in the Overview section above, the worksheet is not for completing the full nuclear gauge density calibration process.

Low or Standard Density Series

When the standard type of reference density blocks has been used for the calibration, the worksheet is completed by entering the number of Test Depths (10 in this example), and then completing the Density Series grid with data from the external calibration certificate.

Some external calibration certificates may display the calibration equation in the form:

And include a statement like (example only): The density range for which this calibration is valid is between the range 1.441 t/m³ to 2.721 t/m³

In this case, on the QESTLab worksheet: -Q from the external certificate is the slope and P is the intercept at each test depth.

If the minimum and maximum density range over which the calibration is valid has been provided but not the ratio range, the user will need to back calculate the ratio, using the formula below.

Use ρ from minimum density range to determine Min. Valid Count Ratio (DCR) for the QESTLab worksheet and ρ from maximum density range to determine Max. Valid Count Ratio (DCR).

High Density Series

If the checkbox Enter High Density Series (WA 135.1 Only) is selected then both the Low Density Series grid and High Density Series grids are shown, and will have the same number of rows.

An additional Combined column appears for each row on the High Density Series.

When the Combined cell is set to No on a row in the high density series, it is expected that the Min. Valid Count Ratio and Max. Valid Count Ratio at the same depth in the high and low series have one ratio in common. For example, in the screenshot shown below, the Max. Valid Count Ratio of the High Density Series at depth 100mm matches the Min. Valid Count Ratio at the Low Density Series at depth 100mm.

When the Combined cell is set to Yes on a row in the High Density Series, all values in that row are locked and set to be equal to the corresponding values in the Low Density Series.

Field Descriptions

Prompt	Behaviour/Description

Prompt	Behaviour/Description
Test Depths	The number of depths for which constants and a valid range will be recorded. Changing this number will add or remove rows from both of the Density Series grids. If both the high and low density series grids are present, both will have the same number of rows.
Enter High Density Series (WA 135.1 Only)	If checked, both the low and high density series grids are shown with their respective headings. If unchecked, only the standard grid is used with the heading Density Series.
Depth (mm)	The depth at which the equation applies.
Slope	The slope of the calibration equation.
Intercept	The intercept of the calibration equation.
Min. Valid Count Ratio	The lowest density count ratio where the equation can be applied.
Max. Valid Count Ratio	The highest density count ratio where the equation can be applied.
Combined	A Yes/No drop-down selection shown only on the high density series. If set to Yes then the other values in this row are set to be equal to the values of the corresponding row from the standard density series at the same depth. A blank is equivalent to No. When set to No it is expected that the Min. Valid Count Ratio and Max. Valid Count Ratio at the same depth in the high and low series have one ratio in common.

QEST Platform 5.6 Documentation