Soil Compaction - 2016 (69) PROFICIENCY TESTING PROGRAM REPORT · Report This report is available on the LabSmart Services website. The issue of this proficiency report was authorised

www.labsmartservices.com.au

Soil Compaction - 2016 (69)

PROFICIENCY TESTING

PROGRAM REPORT

Accredited for compliance with ISO/IEC 17043

Copyright: LabSmart Services Pty Ltd

Soil Compaction Proficiency Testing Program - 2016(69)

Copyright: LabSmart Services Pty Ltd Issued - 31 March 2017 Page 1 of 29

Report This report is available on the LabSmart Services website. The issue of this proficiency report was authorised by Peter Young, Director, LabSmart Services Pty Ltd, March 2017. Contact Details

Email: [email protected] Mobile: 0432 767 706 Fax: (03) 8888 4987

Program Coordinator The program coordinator for this program was Peter Young, Director, LabSmart Services Pty Ltd. Contact Details

Email: [email protected] Mobile: 0432 767 706 Fax: (03) 8888 4987

Acknowledgements Please note that any technical questions regarding this program are to be directed to the program coordinator.

Accredited Proficiency Testing Provider LabSmart Services is accredited by NATA to ISO/IEC 17043, Conformity assessment – General requirements for proficiency testing. Accreditation number 19235. The accreditation provides additional assurance to participants of the quality and importance we place on our proficiency testing programs.

LabSmart Services As well as proficiency testing programs LabSmart Services also offers nuclear gauge calibration. Please see our website for further details.

www.labsmartservices.com.au

Copyright This work is copyright. No part of this publication may be reproduced in any form, transmitted or stored in any repository (e.g. mechanical, digital, electronic or photographic) without prior written permission of LabSmart Services Pty Ltd. Please contact LabSmart Services should you wish to reproduce any part of this report.

Amendment History Reports may be downloaded from the LabSmart Services website.

Version 1 – Issued 31 March 2017



CONTENTS PAGE

1. Program Aim

4

2. Performance

2.1 Identified outliers 2.2 Program summary

4

4 5

3. Technical Comment

3.1 Part A 3.2 Part B

6 6 8

4. Statistics: Z – Score & Graph

4.1 Part A - Maximum Dry Density (MDD) 4.2 Part A - Optimum Moisture Content (OMC) 4.3 Part B - Maximum Dry Density (MDD) 4.4 Part B - Optimum Moisture Content (OMC)

12

12 14 16 18

5. Program Information 5.1 Z-score summary 5.2 Program Design 5.3 Sample Preparation 5.4 Packaging and Instructions 5.5 Quarantine 5.6 Sample Dispatch 5.7 Homogeneity Testing 5.8 Participation 5.9 Statistics

20

20 22 22 22 22 22 23 23 24

Appendix A Instructions for testers Appendix B Results log Appendix C Participant supplied test information

26

27

29



1. Program Aim The proficiency testing program was conducted in November 2016 with 54 participants throughout Australia. The program involved the performance of the following tests.

▪ Standard Maximum Dry Density (MDD)

▪ Standard Optimum Moisture Content (OMC) AS 1289.5.1.1 was the preferred testing method but other equivalent methods were accepted. Each participant’s performance is statistically assessed and used as a measure of their competency relative to all those who participated. The program provides feedback and confidence to participants and the industry regarding the competency of laboratories to perform these tests. Details relating to the design and conduct of the program can be located in section 5.

2. Performance

2.1 Identified outliers Overall a satisfactory level of testing was achieved by the majority (94%) of the 53 participants returning results. There were 3 participants identified as having an outlier (6%). Participant’s test results are tabulated in section 4 along with the robust statistics and a z-score graph. The z-score indicates how far away a participant is from the program’s median value. A z-score of zero indicates a strong consensus with respect to all other participants and represents a very good outcome. The z-score graph gives a quick visual indication of how a result compares to others in the program. Outliers are classified as z-scores where the z-score value was greater than 3 or less than -3. It is recommended that participants with outliers investigate their performance of the test. Participants with outliers are detailed in table 2.1. Those participants with z-scores greater than 2 or less than -2 may wish to review their testing methodology. Only those approaching 3 (outside ± 2.75) have been specifically identified in table 2.1 as feedback. More detail on the robust statistics used can be found in section 5. Technical comment and feedback in section 3 is provided to assist participants investigate or review their results as well for those seeking to improve their testing performance.



Proficiency Component Test Investigate Review*

Part A Soil Sample

Maximum Dry Density (MDD) T5 -

Optimum Moisture Content (OMC) T5 -

Part B Reference Data

Maximum Dry Density (MDD) N7 -

Optimum Moisture Content (OMC) P2 -

* These are not considered outliers, but may wish to review their results. Only z-scores greater than 2.75 and less than -2.75 have been identified in the above table.

Table 2.1 Identified outliers

2.2 Program Summary There were 54 participants that applied for the proficiency testing program. Of these 53 participants returned results in time to be included in the final report. The majority of participants (94%) performed well in this program. The spread of results was very small with standard deviations within the ranges expected. The overall spread of the program compares favourably to the precision suggested by the standard for both OMC and MDD. Laboratories should consider plotting air voids on compaction graphs and check that air voids when plotted are meaningful. The following (table 2.2) is a summary of the results obtained. Normalized IQR values approximate standard deviations.

Statistic

Part A - Soil Sample Part B - Reference Data

MDD OMC MDD OMC

t/m3 % t/m3 %

Number of participants 53 53 48 48

Median 1.850 14.5 2.168 7.2

Normalized IQR 0.017 0.37 0.005 0.09#

CV (%) 0.9 2.6 0.2 1.2

Min* 1.817 13.5 2.155 7.0

Max* 1.877 15.5 2.182 7.4

Range* 0.060 2.0 0.027 0.4

* Minimum, Maximum and Range are calculated with outliers excluded. # Standard deviation used.

Table 2.2 Summary Statistics

The proficiency testing program indicates a satisfactory level of testing and within industry expectations.



The proficiency program was a useful exercise, allowing participants to have greater confidence in their results while for others providing an opportunity to improve their competency with respect to the test methods covered.

3. Technical Comment 3.0.1 Test Methodology

Participants were requested to provide a number of additional details about the testing performed. These details may be used to help analyse the proficiency program results. In addition, the information can help with the investigation of outliers arising from the program. See Appendix C for participant responses. Three participants used Qld methods while all other participants nominated the test methods used as AS 1289.5.1.1 and AS 1289.2.1.1. All participants reported that they used the ‘A’ sized mould. Eight participants used mechanical compaction (L8, D6, Q8, A4, X9, Y7, T5 & V9). These were analysed separately and the median/average values were similar. The standard deviations were slightly better for those using mechanical. (The comparison is based on comparing the statistics from 45 participants to

those from 8 participants.) Most participants used the same graphing technique for both Part A & B with only two participants using a different approach for Part B. 3.02 Soil Curing

There was a large range of curing times used which suggests there is no set approach to this within the industry. The standard suggests a minimum of 2 hours curing time. There were four participants (L7, F4, C6 & L6) that cured for less than this time. The MDD/OMC results however did not reflect a better or worse variation in results obtained when compared to the cure time used. 3.1 Part A One participant (X4) did not return results. There were two outliers identified for Part A of the program by the same participant (T5). 3.1.1 Maximum Dry Density (MDD) & Optimum Moisture Content (OMC)

There was one participant (T5) with an outlier for both MDD and for OMC that needs to investigated. The graph produced was better than most participants. Unfortunately, it did not show the zero air voids line. As with a CBR graph the compaction graph is very useful in checking that both the data obtained and the OMC/MDD determined is reasonable.



The data from T5 was re-graphed. The wet leg did not correspond to the zero air voids line. Moisture was evenly spaced at around 2 % for each compaction. Re-graphing did not yield any improvement in the results obtained. The second and third compactions however gave very similar compaction densities even though the moisture difference was 2 %. This would indicate that one of these two results could be incorrect. In addition, as the densities are so close it distorts the curve around the maximum point i.e. very flat, that could give rise to an incorrect interpretation of the maximum point on the curve. Three of the four compaction densities obtained are higher than the program median value. This would suggest a systematic issue may be involved. The compaction process used should be examined. Mechanical compaction was used. This should be checked as well. 3.1.2 Precision

Reproducibility AS 1289.5.1.1 under section 6 indicates the reproducibility based on ranges and comparing two results from two different laboratories. For both MDD and OMC the maths is the same. Find the difference between two results. Express the difference (range) as a percentage of the average of these two results. Next compare the value obtained to those shown in the test method i.e. 4% for MDD and 20% for OMC. The calculated value should be less than the test method quoted precision to be acceptable. The test method intends this approach to be used for comparing the single result from each of two laboratories. Without further information, as to the approach used to derive the data shown in the test method it is unclear as to how applicable this may be compared to a proficiency program. If the highest and lowest results from the proficiency program are chosen the following is obtained.

Part A Max Min Range Mean Range/Mean %

Limit Pass

MDD 1.877 1.817 0.060 1.847 3.2 <4 Yes

OMC 15.5 13.5 2.0 14.5 13.8 <20 Yes

Table 3.1 Precision check based on test method limits

The minimum and maximum values from the proficiency program represent the largest variation arising from the proficiency program (outliers excluded). As these are below the limits set in the test method it means all other participants also meet the limits indicated in the test method.



Repeatability Determination of repeatability was not part of this proficiency program. 3.2.3 Graphing

The test method indicates that a graph must be prepared in order to derive the OMC and MDD. Graphing the results is also the most practical approach for assessing the correct performance of this test and reliability of the result obtained. Unfortunately, the test method does not adequately define the derivation of the graph or other important aspects pertinent to the accuracy of this test. For example, it does not define when a result should be rejected. At least one participant had the same density value on the dry side for two quite different moisture contents. Clearly one is incorrect. Under the test method this is allowed. Experience suggests this is incorrect. This however is just folk-law if it is not in the test method. Many of the result produced in this program may be questionable but perfectly acceptable under the test method. Detailed feedback on graphing is neither possible or useful while the test method allows the quality of the graph to remain so variable. This proficiency program specifically requested graphs to be submitted. The graphing technique used was predominately via software. The quality of graphing has improved considerably over the last six years. There is still however an element of judgement involved and also the chance that the software used has not produced the best outcome. For these reasons ‘Part B’ is an important aspect of the program. Comments on the graphs submitted for Part A and B are covered in section 3.2.2 under ‘Compaction Graph’. 3.2 Part B 3.2.1 Data analysis and graphing

Part B provided participants with a standard set of data and requested that the MDD & OMC be determined. The outcomes reflect only the variation associated with the graphing and interpretation component of the graph. Although the variation is small (see table 2.2) it does contribute significantly to the overall variation. If the graphing variation is removed the variation might look more like 0.017-0.005 = ±0.012 for MDD and 0.37-0.09 = ±0.28 for OMC. The variation observed is similar to the previous program 2015(62) for graph variation. Two participants (N7 & P2) had outliers for Part B. Both need to investigate the cause of these outliers.



It is strongly recommended that participants with z-scores greater than 2 or less than -2 should also investigate the graphing approach used. 3.2.2 Compaction Graph

The compaction graph gives a visualization of the test results. It is useful as a quick means of determining how well the test has been performed. This is conveyed through the “fit” of the curve to the points and spacing of the compaction points. An “air voids line” can be a very useful addition. The air voids line slope and y-intercept is determined by the soil particle density (See graph 3.2-A). It is important to note that it curves. The soil particle density may have been determined experimentally or as approximated via the ‘Note’ under clause 5(d) of AS 1289.5.1.1. Soil particle density = 1 / [ {(100 x (1 - (A/100))) - (B x C)} / (B*100) ] A = 0% Air Voids B = Dry density of the wettest compaction point C = Moisture at wettest compaction point plus 1% The test method note indicates that a 2% void line when plotted using this particle density should lie close to the compaction curve produced.

Graph 3.2-A

Void lines can be plotted at various amounts of entrapped air. See graph 3.2-B. Often 0 %, 2% or 5 % air void lines are useful. The ‘wet leg’ of a compaction curve should run approximately parallel to the 0 % air void line. The compaction curve plotted must also lie to the left of the 0% air void line. The dry leg should match the wet leg in slope (i.e. match the voids line). Compaction curves not corresponding to this should be investigated.

1.40

1.50

1.60

1.70

1.80

1.90

2.00

2.10

2.20

2.30

2.40

2.50

2.60

2.70

2.80

2.90

3.00

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0

Dry

Den

sit

y (

t/m

3)

Moisture Content (%)

Zero Air Voids

Soil particle density 2.8

Soil particle density 2.6



Many laboratories plot one or more air void lines using an assumed particle density. This often does not convey the information needed to fully interpret the plotted results.

Graph 3.2-B

Soil particle densities lie generally between 2.6 and 2.8. The use of the equation as noted in the test method gives a more meaningful 2 % air void line. It is recommended that laboratories should consider showing air void lines. The air void line should be identified and the particle density used indicated. All graphs submitted were assessed. Some general comments covering the graphs submitted are detailed in (Table 3.2C). The correctness of void lines shown on participant’s graphs was not checked. Graphs were accessed as satisfactory provided they looked ‘reasonable’. Correct plotting of points etc. was not accessed. As to the graphs ‘fit-for-purpose’ it is clear many of the submitted graphs could be improved but it is up to laboratories to determine what best suits both their needs and those of their clients. Approximately 21% of participants did not show any void line(s) on the graph supplied. In line with the comments above these participants are encouraged to consider adding these in the future. Participant R5 used the graphical solution found in RTA method T111.

1.40

1.50

1.60

1.70

1.80

1.90

2.00

2.10

2.20

2.30

2.40

2.50

2.60

2.70

2.80

2.90

3.00

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0

Dry

Den

sit

y (

t/m

3)

Moisture Content (%)

Air Voids - Soil Partcle Density of 2.60

0 % Air Voids

2 % Air Voids

5 % Air Voids



Part A - Graph Part B- Graph

Code Satisfactory Hand Drawn

Void line shown

Satisfactory Hand Drawn

Void line shown

J6 Yes Yes Yes Yes

D9 Yes Yes Yes Yes U4 Yes No Yes No G6 Yes No Yes No N7 NG NG

X4 NR NR

Y9 Yes Yes Yes Yes M7 Yes No Yes No Q3 Yes No Yes No Y8 Yes No Yes No E7 NG NG

J8 Yes Yes NR

P2 Incomplete Yes NG

M4 Small No NG

Z2 Yes Yes Yes Yes L8 NG NG

R9 Yes Yes Yes Yes D6 Yes Yes Yes Yes V3 Yes Yes No Yes Yes No K2 Yes Yes Yes Yes L7 Yes Yes Yes Yes Q8 Yes Yes Yes No A4 Yes Yes Yes Yes L5 Yes Yes NR

X9 Yes Yes Yes Yes Y7 Yes Yes Yes Yes V2 Yes Yes Yes Yes R2 Yes Yes Yes Yes X5 Yes Yes Yes Yes Yes Yes F4 Yes Yes Yes Yes W3 Yes Yes Yes Yes C6 Yes Yes Yes Yes Z9 Yes Yes Yes Yes S5 Yes Yes Yes Yes A9 Yes Yes Yes Yes T3 Yes Yes Yes Yes K7 Yes Yes Yes Yes N5 Yes Yes Yes Yes No Z3 Yes No Yes No Q6 Yes Yes Yes Yes Y2 Yes Yes Yes Yes T7 Yes Yes Yes Yes P9 NG Yes No V7 Yes Yes Yes Yes Yes Yes G2 Yes Yes No Yes Yes No T5 Yes No Yes No V8 Yes Yes Yes Yes G9 NG NR

Y4 Yes Yes NR

L6 Yes Yes NR

V9 NG NG

E8 Yes Yes Yes Yes Q2 Yes Yes Yes Yes R5 Yes Yes No Yes Yes No

Note: Graphs were computer produced unless shown otherwise. NR = No Results submitted NG = No graph supplied

Table 3.2C



J6 1.826 -1.41 X5 1.848 -0.12

D9 1.817 -1.94 F4 1.850 0.00

U4 1.838 -0.70 W3 1.865 0.88

G6 1.828 -1.29 C6 1.857 0.41

N7 1.854 0.23 Z9 1.876 1.52

X4 S5 1.860 0.59

Y9 1.830 -1.17 A9 1.858 0.47

M7 1.847 -0.18 T3 1.824 -1.52

Q3 1.827 -1.35 K7 1.852 0.12

Y8 1.834 -0.94 N5 1.851 0.06

E7 1.854 0.23 Z3 1.837 -0.76

J8 1.8663 0.96 Q6 1.830 -1.17

P2 1.843 -0.41 Y2 1.855 0.29

M4 1.872 1.29 T7 1.846 -0.23

Z2 1.857 0.41 P9 1.865 0.88

L8 1.862 0.70 V7 1.838 -0.70

R9 1.854 0.23 G2 1.819 -1.82

D6 1.851 0.06 T5 1.930 4.69 #

V3 1.864 0.82 V8 1.834 -0.94

K2 1.842 -0.47 G9 1.825 -1.47

L7 1.836 -0.82 Y4 1.833 -1.00

Q8 1.835 -0.88 L6 1.836 -0.82

A4 1.853 0.18 V9 1.830 -1.17

L5 1.851 0.06 E8 1.832 -1.06

X9 1.847 -0.18 Q2 1.853 0.18

Y7 1.854 0.23 R5 1.877 1.58

V2 1.860 0.59

R2 1.851 0.06

Number of results 53

Median 1.850

Median MU 0.003

First Quartile 1.834

Third Quartile 1.857

IQR 0.023

Normalised IQR 0.017

CV (%) 0.9

Minimum 1.817 (1.817)

Maximum 1.877 (1.930)

Range 0.060 (0.113)

Note: A # indicates an outlier where the z-score obtained is either greater then

3 or less than -3. Codes for all participates are shown. The results column

shows a blank entry for those participants that did not submit a result for this

test. Minimum, Maximum and Range are calculated with outliers excluded,

those in brackets include outliers. Particpants results that have been corrected

are shown in green.

4.1 Part A - Maximum Dry Density: Z - Scores

Code

Test

Result

t/m3

Z Score Code

Test

Result

t/m3

Z Score

Statistic Value



ReviewWeak

Consensus

Weak

ConsensusReview

Z-score

Strong Consensus

4.1 Part A - Maximum Dry Density: Z - Score Graph

T5

R5

Z9

M4

J8

W3

P9

V3

L8

V2

S5

A9

Z2

C6

Y2

N7

E7

R9

Y7

A4

Q2

K7

D6

L5

R2

N5

F4

X5

M7

X9

T7

P2

K2

U4

V7

Z3

L7

L6

Q8

Y8

V8

Y4

E8

Y9

Q6

V9

G6

Q3

J6

G9

T3

G2

D9

-3 -2 -1 0 1 2 3



J6 14.5 0.00 X5 13.6 -2.43

D9 14.3 -0.54 F4 14.8 0.81

U4 13.8 -1.89 W3 14.6 0.27

G6 15.0 1.35 C6 14.8 0.81

N7 14.2 -0.81 Z9 14.3 -0.54

X4 S5 14.1 -1.08

Y9 14.8 0.81 A9 14.4 -0.27

M7 14.8 0.81 T3 15.3 2.16

Q3 15.1 1.62 K7 14.4 -0.27

Y8 14.7 0.54 N5 14.7 0.54

E7 14.1 -1.08 Z3 14.6 0.27

J8 14.1 -1.08 Q6 15.5 2.70

P2 14.9 1.08 Y2 14.0 -1.35

M4 14.3 -0.54 T7 14.5 0.00

Z2 14.7 0.54 P9 14.7 0.54

L8 13.9 -1.62 V7 14.8 0.81

R9 14.7 0.54 G2 15.3 2.16

D6 14.7 0.54 T5 12.6 -5.13 #

V3 13.5 -2.70 V8 14.1 -1.08

K2 14.5 0.00 G9 15.08 1.56

L7 13.9 -1.62 Y4 14.5 0.00

Q8 14.9 1.08 L6 14.2 -0.81

A4 14.4 -0.27 V9 14.3 -0.54

L5 14.5 0.00 E8 14.7 0.54

X9 14.4 -0.27 Q2 14.6 0.27

Y7 14.5 0.00 R5 14.1 -1.08

V2 14.2 -0.81

R2 13.8 -1.89


Median 14.5

Median MU 0.06

First Quartile 14.2

Third Quartile 14.7

IQR 0.50

Normalised IQR 0.37

CV (%) 2.6

Minimum 13.5 (12.6)

Maximum 15.5 (15.5)

Range 2.0 (2.9)






are shown in green.

4.2 Part A - Optimum Moisture Content: Z - Scores

CodeTest

Result %

Z Score CodeTest

Result %

Z Score

Statistic Value



ReviewWeak

Consensus

Weak

ConsensusReview

Z-score

Strong Consensus

4.2 Part A - Optimum Moisture Content: Z - Score Graph

Q6

T3

G2

Q3

G9

G6

P2

Q8

Y9

M7

F4

C6

V7

Y8

Z2

R9

D6

N5

P9

E8

W3

Z3

Q2

J6

K2

L5

Y7

T7

Y4

A4

X9

A9

K7

D9

M4

Z9

V9

N7

V2

L6

E7

J8

S5

V8

R5

Y2

L8

L7

U4

R2

X5

V3

T5

-3 -2 -1 0 1 2 3



J6 2.168 0.00 X5 2.160 -1.54

D9 2.163 -0.96 F4 2.170 0.39

U4 2.169 0.19 W3 2.168 0.00

G6 2.169 0.19 C6 2.168 0.00

N7 2.192 4.63 # Z9 2.168 0.00

X4 S5 2.172 0.77

Y9 2.178 1.93 A9 2.168 0.00

M7 2.164 -0.77 T3 2.171 0.58

Q3 2.164 -0.77 K7 2.171 0.58

Y8 2.164 -0.77 N5 2.175 1.35

E7 2.165 -0.58 Z3 2.166 -0.39

J8 Q6 2.170 0.39

P2 2.161 -1.35 Y2 2.168 0.00

M4 2.169 0.19 T7 2.170 0.39

Z2 2.171 0.58 P9 2.176 1.54

L8 2.171 0.58 V7 2.155 -2.51

R9 2.171 0.58 G2 2.182 2.70

D6 2.171 0.58 T5 2.164 -0.77

V3 2.162 -1.16 V8 2.160 -1.54

K2 2.168 0.00 G9

L7 2.165 -0.58 Y4

Q8 2.170 0.39 L6

A4 2.164 -0.77 V9 2.166 -0.39

L5 E8 2.164 -0.77

X9 2.169 0.19 Q2 2.164 -0.77

Y7 2.169 0.19 R5 2.155 -2.51

V2 2.180 2.31

R2 2.164 -0.77


Median 2.168

Median MU 0.001

First Quartile 2.164

Third Quartile 2.171

IQR 0.007

Normalised IQR 0.005

CV (%) 0.2

Minimum 2.155 (2.155)

Maximum 2.182 (2.192)

Range 0.027 (0.037)






are shown in green.

4.3 Part B - Maximum Dry Density: Z - Scores

Code

Test

Result

t/m3

Z Score Code

Test

Result

t/m3

Z Score

Statistic Value



ReviewWeak

Consensus

Weak

ConsensusReview

Z-score

Strong Consensus

4.3 Part B - Maximum Dry Density: Z - Score Graph

N7

G2

V2

Y9

P9

N5

S5

Z2

L8

R9

D6

T3

K7

Q8

F4

Q6

T7

U4

G6

M4

X9

Y7

J6

K2

W3

C6

Z9

A9

Y2

Z3

V9

E7

L7

M7

Q3

Y8

A4

R2

T5

E8

Q2

D9

V3

P2

X5

V8

V7

R5

-3 -2 -1 0 1 2 3



J6 7.4 2.43 X5 7.0 -2.09

D9 7.0 -2.09 F4 7.2 0.17

U4 7.2 0.17 W3 7.2 0.17

G6 7.2 0.17 C6 7.2 0.17

N7 7.1 -0.96 Z9 7.2 0.17

X4 S5 7.2 0.17

Y9 7.1 -0.96 A9 7.2 0.17

M7 7.2 0.17 T3 7.2 0.17

Q3 7.2 0.17 K7 7.2 0.17

Y8 7.2 0.17 N5 7.2 0.17

E7 7.2 0.17 Z3 7.4 2.43

J8 Q6 7.0 -2.09

P2 7.5 3.56 # Y2 7.2 0.17

M4 7.2 0.17 T7 7.1 -0.96

Z2 7.2 0.17 P9 7.1 -0.96

L8 7.2 0.17 V7 7.2 0.17

R9 7.2 0.17 G2 7.3 1.30

D6 7.2 0.17 T5 7.2 0.17

V3 7.1 -0.96 V8 7.0 -2.09

K2 7.2 0.17 G9

L7 7.2 0.17 Y4

Q8 7.2 0.17 L6

A4 7.2 0.17 V9 7.4 2.43

L5 E8 7.3 1.30

X9 7.2 0.17 Q2 7.2 0.17

Y7 7.2 0.17 R5 7.1 -0.96

V2 7.1 -0.96

R2 7.2 0.17


Average 7.19

Average MU 0.016

First Quartile NA

Third Quartile NA

IQR NA

Standard Deviation 0.09

CV (%) 1.2

Minimum 7.0 (7.0)

Maximum 7.4 (7.5)

Range 0.4 (0.5)






are shown in green.

4.4 Part B - Optimum Moisture Content: Z - Scores

Code

Test

Result

%

Z Score Code

Test

Result

%

Z Score

Statistic Value



ReviewWeak

Consensus

Weak

ConsensusReview

Z-score

Strong Consensus

4.4 Part B - Optimum Moisture Content: Z - Score Graph

P2

J6

Z3

V9

G2

E8

U4

G6

M7

Q3

Y8

E7

M4

Z2

L8

R9

D6

K2

L7

Q8

A4

X9

Y7

R2

F4

W3

C6

Z9

S5

A9

T3

K7

N5

Y2

V7

T5

Q2

N7

Y9

V3

V2

T7

P9

R5

D9

X5

Q6

V8

-3 -2 -1 0 1 2 3



5. Program Information

5.1 Z-score summary The proficiency program was conducted in November 2016. A ‘Z-score Summary’ summary was issued on the 28 December 2016. A copy was e-mailed to all participants who submitted results. The summary is intended as an early indicator of participant performance. This program report supersedes the z - score summary. Further information can be found in section 5.9 ‘Statistics’. The z-scores generally do not vary significantly between the “summary” and the “Final Report”. An additional set of participant results have been included but this has not significantly affect the statistics or performance outcomes.

5.2 Program design 5.2.1 Design

Part of the design of each program involves asking for the right information. The correct analysis of the data collected then allows feedback to be offered to enable participants to improve in the performance of this test. In designing a proficiency program, it is sometimes necessary to minimise the effect of some inherent test method variability. E.g. By providing the OMC and MDD value to be used for a CBR program. At other times the use of different materials gives a better indication of performance than using a single “easy” material. Test methods often have more than one area where skill and technique have an effect. Where possible a proficiency testing program may be designed to test different aspects of the method. In this program the overall performance of the test is covered by ‘Part A’. The skill associated with graphing and data interpretation has been separated out by giving the same test results to all participants in ‘Part B’. This also gives a measure of the variably associated with just this part of the test method. The program was designed to provide technical feedback regarding performance as well as possible improvements in performance. Other considerations involving the design of the program are detailed below. 5.2.2 Selection of material used in the program

The test in this proficiency program is operator skill/experience dependant. In addition, certain types of soils require more knowledge to obtain consistent results than others. Different materials are selected for each program to mirror the range of materials encountered in practice. This program provides a sample that gives results in the range that would be commonly tested by laboratories.



It is expected that the level of experience/skill need to perform these tests will present a reasonable assessment of the overall competency of the tester and industry performance. 5.2.3 Role of proficiency testing

The determination of outliers is an important task of this proficiency program. A secondary function is to provide feedback that can help those with outliers identify possible areas to investigate as well as assist all participants to improve. In addition to the statistics, proficiency programs often obtain other information that is not normally available to a laboratory. It allows for a better understanding of the testing and can provide information that can lead to improvements in the testing process or test method. Proficiency testing enables participants to measure competency against others. It is also a measure of staff performance and the equipment used. Apart from ‘measurement uncertainty’ it is the most useful tool a laboratory has in better understanding the performance of a test. 5.2.4 Participant assessment

Assessment of each participant is based on a z-score that is related to the program consensus value (median). This is used to determine any statistical outliers. Compliance to proficiency program requirements including the correct calculation of results and adherence to program and test method requirements may also be used as part of the assessment process. Participants may also be asked to investigate any discrepancies detected with the paperwork submitted. 5.2.5 Reporting of results - Significant figures

The number of decimal places (significant figures) reported for a test has a bearing on the statistical analysis and therefore the interpretation of the results. There is a need to strike a balance between what is desirable from a statistical viewpoint while recognising how the results are used in practice. Too few decimal places (e.g. due to rounding) can cause an increase in the observed spread of results. Increasing the number of decimal places (with respect to normal reporting) can distort the observed spread of results compared to that encountered in actual practice. Large numbers of similar, rounded results can also cause a distortion in the analysis. For example, rounding to 0.5 % means that any number between 10.75 and 11.25 will be 11.0%. If the largest value is 10.75 in a set of results it is pushed out to 11.0 through rounding. Rounded results are useful from “an end user” perspective but are not as useful when considering laboratory performance. The test method acknowledges additional decimal places may be used for statistical purposes. For this program, it was decided that the benefits of using additional decimal places would complement the aim of the proficiency program.



Participants results were analysed as received regardless of whether there were more or less significant figures than the number requested by the program. 5.2.6 Additional information requested

This program requested additional information as detailed in Appendix C not usually reported. The additional information is however consistent with the performance of the test and the records the test method requires laboratories to maintain. The additional information is used to interpret participant’s performance and assist with providing technical comment including feedback on outliers and possible participant improvement. 5.3 Sample Preparation Samples for the program were drawn and packaged from a single, well mixed, lot. Samples were laid out in the order prepared. Ten samples were selected at approximately equal intervals from the set of samples. These were used for homogeneity testing. Each participant received randomly drawn samples from the remainder. A unique participation code was assigned to each sample. Each sample was placed in a plastic bag, sealed, labelled with the program name and packed into a sturdy box prior to dispatch. 5.4 Packaging and Instructions Each participant received one sealed plastic bag, marked ‘Soil Compaction Proficiency Program – 2016 (69) Sample’, containing approximately 14 kg of soil. Participants were instructed to test per the nominated test method and report to the accuracy indicated on the ‘results log’ sheet. See ‘Appendix A’ for a copy of the instructions issued to participants and ‘Appendix B’ for the log sheet used. 5.5 Quarantine Samples sent to Western Australia are subject to quarantine regulations that require treatment of the soil prior to importation. Samples sent to WA are heat treated and compliance certificates enclosed with samples. Where applicable further instructions regarding preparation or handling of the sample may be included. 5.6 Sample dispatch Samples were dispatched to participants on the 14 November 2016 using Toll Priority. Dispatched samples are tracked from despatch to delivery to each participant by LabSmart Services.



5.7 Homogeneity Testing Samples for homogeneity testing were packed in the same way as those for participants. Ten samples were selected at approximately equal intervals throughout the set of samples. To approximate the same conditions as participants the same instructions were given to the laboratory performing the homogeneity testing. Analysis of the homogeneity testing results indicated one homogeneity sample was an outlier and rejected. Associated worksheets also confirmed the decision to reject this sample results. The remaining nine homogeneity samples were further analysed (Table 5.7) and indicated that the variability associated with the proficiency samples was satisfactory. The average of the homogeneity samples also lies within 1 s.d of the participant’s median value. This provides confidence that any outliers identified in the program represent statistically valid outliers. 5.8 Participation Fifty-four participants entered the program with a total of 53 results received. The nominated date for participants to return their results was 30 November 2016. There was one participant unable to return their results in time for inclusion in the final report. The z-score summary included 52 participants while the final program report included 53 participants.

Sample Code MDD t/m3

OMC %

H1 1.841 14.3

H2 1.830 14.4

H3 1.841 14.3

H4 1.840 14.2

H5 1.834 14.8

H6 1.840 14.6

H7 1.840 14.3

H8 1.840 14.3

H9 1.831 14.5

Average 1.837 14.4

Standard Deviation 0.004 0.19

Minimum 1.830 14.2

Maximum 1.841 14.8

Range 0.011 0.6

Coefficient of Variation (%) 0.2 1.3

Table 5.7 Homogeneity Results



5.9 Statistics Z-Scores were calculated for each test and used to assess the variability of each participant relative to the consensus median. A corresponding z-score graph was produced for each test. The use of median and quartiles reduces the effect that outliers have on the statistics and other influences. As a consequence, z-scores provide a more realistic or robust method of assessment. Some results were reported by participants to more decimal places than requested as part of the proficiency program and by others to fewer decimal places. In all instances test results have been used as submitted by participants.

A z-score is one way of measuring the degree of consensus with respect to the grouped test results. The z-scores in this report approximate standard deviations. For each test a z-score graph is shown. Use the graph to visually check statistically how you compare to other participants. The following bar (Figure 5.2) is shown at the bottom of each graph. This helps to quickly visualize where each participant’s result falls.

Review Weak

Consensus Strong Consensus

Weak Consensus

Review

Figure 5.2 Z-score interpretation bar

For example:

• A strong consensus (i.e. agreement) means that your test result is close i.e.

within 1 standard deviation of the median.

• A weak consensus means that your test result is satisfactory and is within 2

standard deviations of the median.

• If you have obtained a test result that is outside 2 standard deviations, then it

may be worth reviewing your testing processes to ensure that all aspects are

satisfactory. Only those obtaining a z-score approaching 3 (I.e. outside 2.75 range) have been highlighted in the report for review.

If you have obtained a test result that is outside 3 standard deviations then you will need to investigate your testing processes to ensure that all aspects are satisfactory. For further details on the statistics used in this proficiency program can be obtained from LabSmart Services or download the ‘Participant Guide’ from the LabSmart Services website. 5.9.1 Z-score summary

A “Z-Scores Summary” is issued soon after most results are received. It gives participants early feedback as to any program outliers. The summary is usually



available on the LabSmart Services website up until the final report is issued. The final report supersedes the z-score summary. The final report contains detailed technical feedback regarding the performance of tests and revised z-scores. The inclusion of late results or corrections are at the discretion of the program coordinator. In some instances, this may change some of the z-scores slightly but generally the performance outcome remains the same. If there is any impact it will be discussed within section 5.1 of the report. 5.9.2 Comparing statistics from one program to another

The statistics generated from one proficiency program are not usually comparable to those from another proficiency testing program. Only very general comparisons may be possible. The reason statistics from one program may not be compared to another is due to the range of variables that differ from one proficiency program to another. These variables include:

• Type of material selected,

• The number of participants,

• Experience of participants,

• Test methodology variations,

• Equipment used,

• Test methods used,

• Experience of supervisors,

• Range of organisations involved.

• Program design and the statistics employed. The program outcome represents a ‘snap shot’ of the competency within the industry and hence provides an overview of the industry. The more participants involved in the program then the more representative the overview. 5.9.3 Measurement uncertainty

The statistics detailed in this program do not replace the need for laboratories to separately calculated measurement uncertainties associated with each test when required by the client or NATA. The proficiency program does give information useful for calculating the MU and bench marking the MU calculated. 5.9.4 Metrological traceability

The assigned median value used in this proficiency testing program is derived from participant performance and is not metrologically traceable.



Appendix A - PT Instructions V3 Compaction 2016(69).docx

LabSmart Services

Soil Compaction Proficiency Testing Program – 2016(69)

INSTRUCTIONS FOR TESTERS

1. Please check that the package you have received contains the following:

• Instructions (for testers)

• Results Log

• Approximately 14 kg soil sample sealed in a plastic bag.

Contact Peter on 0432 767 706 if the bag is damaged or any item is missing.

2. Please read and follow these instructions carefully. Examine the results log sheets. There is a Part A and a Part B to the proficiency program.

3. Please do not discuss aspects of this program with other organisations or other staff

within your own organisation who may also be testing a sample from this program. Confidentiality is important in order to ensure statistically valid measures of participant performance.

PART A

4. Due to segregation during transit please ensure the sample is thoroughly mixed prior

to starting.

5. AS 1289 test methods are the preferred test methods.

6. You may perform the test even if you are not NATA accredited for the test. The use of mechanical compaction is allowed.

7. Sieve the sample over the 19.0 mm sieve. Discard any material retined on the 19.0 mm

sieve. Thoroughly mix the material passing the 19.0 mm sieve and use for the compaction test.

8. Record all information and calculations as per the proficiency testing results log sheet

and to the accuracy shown on the results log sheet. A greater reporting accuracy is required compared to that nominated by the standard. Please forward graph used.

PART B 9. Use the moisture/dry density data shown under ‘Part B’ of the results log sheet. 10. Calculate the OMC and MDD for this data set using the same procedure as used in

‘Part A’ if possible. Enter your results onto ‘Part B’ of the results log. Please forward graph used.

11. If you are unable to use the same procedure as used in ‘Part A’ then use an alternative

method (e.g. manually graph etc).

Please fax or e-mail the “Results Log” to LabSmart Services by 30 November 2016

Fax: (03) 8888 4987 OR E-mail: [email protected]

Thank you for participating in this proficiency program. Page 1 of 1

Appendix A



mailto:[email protected]

Appendix B - Results Log V3 Compaction 2016(69).docx

LabSmart Services

Soil Compaction Proficiency Testing Program – 2016 (69)

RESULTS LOG for XXXXXXXX

Participation Code: XX

Please fax (03) 8888 4987 or e-mail ([email protected]) the completed results log by:

30 November 2016

PART A – Please attach graph

Date sample received:

Condition of sample received:

Tested by:

Name of Laboratory:

Test Report to: Result Method

Recommended Tick or enter method used

Standard Maximum Dry Density (MDD) Nearest 0.001 t/m3 AS 1289.5.1.1

Standard Optimum Moisture Content (OMC) Nearest 0.1 % AS 1289.5.1.1

Method used to determine moisture AS 1289.2.1.1

Data used to construct curve Dry Density Moisture

Report to Nearest 0.001 t/m3 Report to Nearest 0.1 %

Sample 1

Sample 2

Sample 3

Sample 4

Additional test details Report Result

Curing time used Nearest ½ hr

Has a mechanical compactor been used? (Yes or No)

Mould size used A or B

Number of blows used per compaction layer Blows

Page 1 of 2

Appendix B



mailto:[email protected]

Appendix B - Results Log V3 Compaction 2016(69).docx

PART B – Please attach graph

Data used to construct curve Dry Density Moisture

Sample 1 1.954 3.8

Sample 2 2.145 6.1

Sample 3 2.140 8.5

Sample 4 2.076 9.8

NOTE: If you are only able to use a three point method then use data for samples 1, 2 and 3 only.

Test Report Result

Standard Maximum Dry Density (MDD) Nearest 0.001 t/m3

Standard Optimum Moisture Content (OMC) Nearest 0.1 %

Method of determining OMC & MDD same as Part A?

(Yes or No)

COMMENTS:…………………………………………..............…………………… ………………………………...........................………..........…...……………………………………………………...........................………..........…...……………… …………………………………...........................………..........…...………………

------------------------------------ ---------------------------------- --------------- Supervisor Name (Please Print) Signature Date

In signing the above I acknowledge that the above results are approved and have been checked. I will also ensure that the results are kept confidential both internal and external to the laboratory until the final technical report covering this program has been issued.

Note:

Please retain the completed “Results Log” as this contains your participation code that will identify your results in the technical report covering the proficiency testing program. It is also recommended that a copy of completed worksheets be kept with the results log in your proficiency file.

Thank you for participating ________________________________________________________________________

Have a query? Contact Peter Young at LabSmart Services. Mobile: 0432 767 706

Page 2 of 2



J6 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

D9 AS 1289.5.1.1 AS 1289.2.1.1 48 No A Yes

U4 AS 1289.5.1.1 AS 1289.2.1.1 24.5 No A Yes

G6 AS 1289.5.1.1 AS 1289.2.1.1 24.0 No A Yes

N7 AS 1289.5.1.1 AS 1289.2.1.1 48 No A Yes

X4 NR NR NR NR NR NR

Y9 AS 1289.5.1.1 AS 1289.2.1.1 20 No A Yes

M7 AS 1289.5.1.1 AS 1289.2.1.1 3 No A Yes

Q3 AS 1289.5.1.1 AS 1289.2.1.1 4 No A Yes

Y8 AS 1289.5.1.1 AS 1289.2.1.1 70 No A Yes

E7 AS 1289.5.1.1 AS 1289.2.1.1 26 No A Yes

J8 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

P2 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

M4 Q142A NR 2 No A Yes

Z2 AS 1289.5.1.1 AS 1289.2.1.1 44.5 No A Yes

L8 AS 1289.5.1.1 AS 1289.2.1.1 4.5 Yes A Yes

R9 AS 1289.5.1.1 AS 1289.2.1.1 3.5 No A Yes

D6 AS 1289.5.1.1 AS 1289.2.1.1 2.5 Yes A Yes

V3 AS 1289.5.1.1 AS 1289.2.1.1 25.0 No A Yes

K2 AS 1289.5.1.1 AS 1289.2.1.1 96 No A Yes

L7 AS 1289.5.1.1 AS 1289.2.1.1 1 No A Yes

Q8 AS 1289.5.1.1 AS 1289.2.1.1 27 Yes A Yes

A4 AS 1289.5.1.1 AS 1289.2.1.1 26.5 Yes A No

L5 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

X9 AS 1289.2.1.1 AS 1289.2.1.1 168.0 Yes A Yes

Y7 AS 1289.2.1.1 AS 1289.2.1.1 168 Yes A Yes

V2 AS 1289.5.1.1 AS 1289.2.1.1 50.5 No A Yes

R2 AS 1289.5.1.1 AS 1289.2.1.1 8 No A Yes

X5 AS 1289.5.1.1 AS 1289.2.1.1 4 No A Yes

F4 Q1421A Q102A 0.5 No A No

W3 AS 1289.5.1.1 AS 1289.2.1.1 21 No A Yes

C6 AS 1289.5.1.1 AS 1289.2.1.1 1.0 No A Yes

Z9 AS 1289.5.1.1 AS 1289.2.1.1 218 No A Yes

S5 AS 1289.5.1.1 AS 1289.2.1.1 24.5 No A Yes

A9 AS 1289.5.1.1 AS 1289.2.1.1 48.0 No A Yes

T3 AS 1289.5.1.1 AS 1289.2.1.1 48 No A Yes

K7 AS 1289.5.1.1 AS 1289.2.1.1 2.5 No A Yes

N5 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

Z3 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

Q6 AS 1289.5.1.1 AS 1289.2.1.1 96 No A Yes

Y2 AS 1289.5.1.1 AS 1289.2.1.1 6 No A Yes

T7 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

P9 Q142A Q102A 20 No A Yes

V7 AS 1289.5.1.1 AS 1289.2.1.1 48.0 No A Yes

G2 AS 1289.5.1.1 AS 1289.2.1.1 24 No A Yes

T5 AS 1289.5.1.1 AS 1289.2.1.1 44.0 Yes A Yes

V8 AS 1289.5.1.1 AS 1289.2.1.1 3 No A Yes

G9 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

Y4 AS 1289.5.1.1 AS 1289.2.1.1 2.5 No A Yes

L6 AS 1289.5.1.1 AS 1289.2.1.1 1 No A Yes

V9 AS 1289.5.1.1 AS 1289.2.1.1 0.5 Yes A Yes

E8 AS 1289.5.1.1 AS 1289.2.1.1 24.0 No A Yes

Q2 AS 1289.5.1.1 AS 1289.2.1.1 2 No A Yes

R5 AS 1289.5.1.1 AS 1289.2.1.1 43 No A Yes

Appendix C - Particpant Supplied Test Information

Code MDD Method MC Method

Cure

Time

(hrs)

Mechanical

Compaction

Mould

Size

Used

Graph method

same for Part

A & B



Documents

Soil Compaction - 2016 (69) PROFICIENCY TESTING PROGRAM REPORT · Report This report is available on the LabSmart Services website. The issue of this proficiency report was authorised