CBR - 2015 (59) PROFICIENCY TESTING PROGRAM … · The path forward to increasing the reliability of CBR test results is with improving the testing conducted by the middle 50% of

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CBR - 2015 (59)

PROFICIENCY TESTING

PROGRAM REPORT

Accredited for compliance with ISO/IEC 17043

Copyright: LabSmart Services Pty Ltd

CBR - Proficiency Testing Program - 2015(59)

Copyright: LabSmart Services Pty Ltd Report Issued December 2015 Page 1 of 40

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, November 2015. 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 LabSmart Services would like to thank Mr Norm Fieldew for his technical assistance with this program. 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 a wide range of other services including consultancy, training and 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 December 2015



CONTENTS PAGE

1. Program Aim

4

2. Performance

2.1 Identified Outliers 2.2 Focus on Improvement 2.3 Program Summary

4

4 5 6

3. Technical Comment

3.1 Terminology 3.2 Supply of Program Information 3.3 Statistical Reality 3.4 Test Method 3.5 Set SD Limits 3.6 Reproducibility & Repeatability 3.7 General Performance 3.8 Errors 3.9 Testing Reality 3.10 Limitations of Proficiency Testing Programs 3.11 Pre-compaction Curing 3.12 OMC & MDD 3.13 CBR Compaction 3.14 LDR & LMR 3.15 Load & Penetration (Zero Correction) 3.16 Graphing 3.17 Reporting CBR

7

7 7 8 8 8 9 9 10 10 10 10 11 11 11 13 17 18

4. Statistics: Z-Scores & Graph

4.1 CBR 4.2 Set SD Limits

20

20 22

5. Program Information

5.1 Program Design 5.2 Sample Preparation 5.3 Packaging and Instructions 5.4 Quarantine 5.5 Sample Dispatch 5.6 Homogeneity Testing 5.7 Participation 5.8 Statistics

24

24 26 26 27 27 27 27 27

6. Participants’ Test Results

30

Appendix A Instructions for testers Appendix B Results log Appendix C Graphing Feedback

35

37

39



1. Program Aim The proficiency program was conducted in May 2015 with participants throughout Australia. The program involved the performance of AS 1289.6.1.1 (2014) – Determination of the California Bearing Ratio of a soil – Standard laboratory method for a remoulded specimen. The program provides feedback and confidence to the construction materials testing industry regarding the competency of participants (and the industry) to perform this test. Each participant’s performance is statistically assessed and used as a measure of competency relative to all those who participated. This report has been prepared using robust statistics. In addition data has been reviewed for consistency and additional feedback regarding aspects of the test are provided. Comprehensive technical comment is provided to assist participants improve the overall performance of this test (Section 3). Information regarding the conduct and design of the program etc. can be found under section 5.

2. Performance

2.1 Identified Outliers In most proficiency testing programs the identification of outliers is relatively straight forward. Not so for CBR testing. There are a range of factors that make this task difficult.

• The test is prone to large variations in test results • The test method has recently been revised. • The test is material sensitive (as indicated by the different rounding

requirements of the test method) • There are no published guidelines as to the acceptability of reproducibility or

repeatability outcomes for this test. These aspects of the test are discussed in more detail under ‘Technical Comment’, section 3. Despite these drawbacks the test is in common use. Laboratories have a need to better understand both their performance of the test and spread of results to be expected both of which can be gained from proficiency testing programs. The results submitted by each participant are detailed in section 6.0. The highest bearing ratio was at the 5.0 mm penetration and therefore also represents the unrounded CBR value. These results and associated robust statistics are shown in section 4.1 One outlier was identified (G4) using the robust statistics. Although there is a need for this laboratory to review its result from a statistical viewpoint there are technical issues which suggests follow up may not be needed. This is discussed further in the next section, 2.2.



The observed variation (based on CV) is better than other proficiency programs conducted over the last decade. Industry has expressed concerns that from an engineering “End User” perspective that such large variations in CBR results are impractical. It is also unacceptable from a laboratory testing perspective.

2.2 Focus on Improvement Proficiency testing programs that provide technical feedback assist laboratories to improve. All of the technical comment detailed in section 3 has this in mind and is aimed at helping laboratories to have a greater understanding of the test. How can improvement be measured? With CBR testing this is very difficult as comparing previous proficiency testing programs provides limited information. It is understood that as the magnitude of the CBR value increases so does the variation. Low CBR values (20% CBR) will show much lower variation than high CBRs. Perhaps the best way at present to measure improvement is to apply a test such as “Are the results fit for purpose?” A mentioned earlier from an engineering “End User” perspective the results are only useful if material can be assessed from an engineering perspective. This in turn is limited ultimately by what the test method is able to achieve. The test method rounds the final CBR result and this provides some indication as to what can be achieved.

CBR Range (%) Round to the nearest (%)

< 5 0.5

5 to 20 1

20 to 50 5

>50 10 This yields a very crude estimate that the CV should be better than 9.5% between laboratories. It does match the engineering expectations of allowing results to be useful. This ‘bench mark’ has been used in the last few proficiency programs conducted. This is discussed in more detail under ‘Set SD Limit’ in section 3 (Technical Comment). From an engineering perspective a CBR greater than 100% is satisfactory for a soil or low quality stone. Good quality crushed rock will have a CBR value in the order of 250%. Hence the outlier identified in section 2.1 perhaps should not be thought of as an outlier in this instance. Have laboratories improved? The answer is yes. Proficiency programs have been conducted since 2009 and in that time the quality of submitted information has improved enormously.



The CV over this time has been around (30 to 45%) whereas this program has a CV of 20%. While CVs are only a general guide it does show CBR test results are heading in the right direction. This however is outside the 9.5% CV bench mark so there is still a way to go. Future improvement is going to be incremental. The revised test method offers a number of improvements compared to the previous version. The technical comments in this report are focused on many small changes that should yield improvements in testing. As detailed in the technical comments section it is the middle 50% of participants where the most improvement is most needed.

2.3 Overall Performance The statistics used in all proficiency programs is there for guidance. Care needs to be exercised to avoid incorrect conclusions being drawn from the statistics. This is one of the reasons that LabSmart Services provides comprehensive technical comment for each program. There has been an observable improvement in CBR testing over the last six years. It is important to recognize that for CBR proficiency programs the identification of outliers is of limited concern at this time. The path forward to increasing the reliability of CBR test results is with improving the testing conducted by the middle 50% of participants. What this means is that every participant should review the testing submitted against the technical comments made in this report. There are too many matters identified under technical comment (Section 3) to summarise. Much of the variation observed could be reduced if the matters identified under technical comment were addressed. With a revised test method issued retraining of laboratory staff should be a priority for many laboratories. Participation in CBR proficiency programs measures the efficiency of the training provided as well as competency. There is a strong culture in the industry of going with the’ minimum requirement’ at every step of the CBR procedure. This is neither desirable nor appropriate technically in many cases. It has a significant impact on the reliability of the test result. The test method standard is unlikely to change now for some time. It is up to laboratories to improve in order for the industry to be able to issue credible results for this test. This proficiency program provides increased understanding of current test practices and potential sources of variation. It also allows monitoring of improvements in testing and provides the opportunity for participant’s to improve their competency. A summary of the program statistics is shown in Table 2.3.



Statistic BR at 5mm (%)

Number of participants 31

Median 140

Normalized IQR 28.5

Minimum* 110

Maximum* 190

Range* 80

CV (%) 20.4

Table 2.3 Summary of statistics for the CBR program. *Min, Max & Range are with outliers excluded.

3. Technical Comment The following sections give some feedback about performance of the test and ideas that may assist participants in the proficiency program to improve in the performance of this test. 3.1 Terminology The test method refers to intermediate results such as obtained at 2.5mm and 5mm as ‘Bearing Ratios’. It is not until the larger of the two has been selected and rounded does it get called a ‘Californian Bearing Ratio’ in the test method. This proficiency program deals with the largest ‘bearing ratio’ obtained. For further details see section 3.17. This report however does use the term ‘CBR’ as a generic term when discussing the testing process or test method. 3.2 Supply of Program Information A large number of participants supplied all the testing details requested. This information is used to provide the feedback given in the following sections and is an important part of the program. Participants are always welcome to contact the program coordinator if they require further explanation as to what information is required. The information requested is also used to validate the results obtained. Proficiency testing program providers may reject results on this basis if they do not conform to the program requirements.



3.3 Statistical Reality It is easy to draw the wrong inference from statistics. Often proficiency testing programs tend to focus on feedback concerning those with results that seem either too high or too low. Only some of the feedback below is aimed at this group of participants. However the fundamental issue with CBR results is that there is too large a spread shown by the middle 50% of participants. Within this group the results are too spread out. This means that identifying accurately a median value or outliers is compromised. The following comments further backup this assertion. As a consequence every participant should be trying to improve their performance of this test. 3.4 Test Method This is the first proficiency testing program conducted using the new 2014 AS CBR test method. It has made a number of substantial changes and as a consequence retaining of laboratory staff is most likely needed. There were a number of changes made to the method to try and reduce the spread of results obtained. In practice this may not be observed immediately as some participants need time to adjust to a different way of testing hence an improvement in the test variability may not be seen immediately. Normally two samples are provided in order to observe the in-house variation or differences in testing practices. This was not done for this program as it was felt that laboratories need time to adjust to the new CBR test method. It was felt that performing the test twice would not yield sufficient useful information for the extra work needed by participants. Also from a proficiency testing perspective if the testing methodology changes significantly, as it has with the new test method, then care needs to be taken when referencing outcomes from previous programs as these may no longer be comparable. 3.5 Set SD Limits In previous CBR proficiency programs LabSmart Services has given some guidance as to what could be used as an acceptable spread from an “End User” perspective. A variation considered reasonable has been based on ± 9.5 % (coefficient of variation) of the median. Calculated values are shown in table 3.5A.

See Section 4.2

Median CV (%) S.D. Limit

140.0 % 9.5 ± 13.3 %

Table 3.5A Set S.D Limits. Bearing Ratio at 5.0 mm



Please note that the following performance outcomes do not constitute an outlier in this program but provide one approach to determining which participant results may be improved on further review. There are alternative approaches that can be used. See also NATA “Information Paper 9 – Soils testing technical issues” July 2013. Results were recalculated using the above ‘Set SD Limits’ as detailed in section 4.2 Based on these limits, participants exhibiting statistically significant variation are shown in the table below.

CBR (%)

Z-score> 3 Z-score≈ 2.75

Q9, C2, J8, G4 L7, P3

Table 3.5B Statistically significant unrounded CBR results based on a set “SD Limit”.

Participants shown above may find it beneficial to review the performance of this test. Comments in section 3.3 should be considered. Also as all the CBR results shown in table 3.5B are very large from an engineering perspective these would still be considered acceptable. 3.6 Reproducibility & Repeatability As indicated in previous sections there are sound reasons for not comparing one CBR proficiency program with another. If testing variation can be reduced to acceptable levels in the future an estimate of reproducibility may then be possible. This program did not attempt to measure repeatability due to the issue of a revised test method (see section 3.4 for more explanation). 3.7 General Performance General performance covers those aspects of laboratory operations that are expected to be performed as part of good laboratory practice and in keeping with NATA accreditation. Some aspects that are particularly relevant for this program are: Supervision of testing Following the test method Following proficiency testing instructions Correctly filling out paperwork i.e. PT log sheet Checking of results Graphing Reality check of results i.e. does it fit the type of material submitted

Overall compared to previous CBR proficiency testing programs most of the above was done quite well.



Some participants failed to achieve one or more of the above. If all participants meet the above there would be a reduction in the test variation without any change in procedure. It raises the question that if participants are not meeting the above basic requirements then what other errors are occurring during testing. 3.8 Errors Errors may occur from a number of sources, an incorrect calculation, transcription error, wrong methodology used, not following the test method etc. Many of the comments in the following sections relate to errors. With CBR testing a single test where the history is unknown is not the ideal. If the curve looks a little unusual a repeat test may be necessary. See also Appendix B; section B5 of the test method for more guidance. Although some of these may have only a small impact they do accumulate and should not occur. Others can have a large impact such as incorrect graphing technique and zero correction. 3.9 Testing Reality Most laboratories see a variety of CBR samples. From this a feel can be gained as to what CBR range a particular material will give. This knowledge should be used for everyday testing and proficiency testing as well. For the material suppled for this program a CBR greater than 80% may have been predicted. In daily testing the opportunity to perform the test twice on the same material means it should be possible to use the added knowledge to improve the testing outcome. It also gives an indication of what the repeatability with in the laboratory might be. As a ‘checker’ or ‘supervisor’ this type of knowledge can be applied as a ‘reality check’ on the results obtained. 3.10 Limitations of a Proficiency Testing Program Participants are often placed in difficult position when they know or suspect a mistake may have been made during testing. Proficiency programs only send sufficient sample to perform the test once so repeating the test is often not possible. Participants in this situation should write their observations in the comments section of the proficiency testing log sheet so that it can be taken into account during the assessment of results. Alternatively asking the proficiency testing provider for another sample to retest may also be possible. 3.11 Pre-compaction Curing All participants cured the sample prior to compaction for at least 48 hours. A few cured for longer. Samples need to be in sealed containers and the material broken up and mixed regularly during curing. The curing times specified by the test method are minimums. More curing is better than less.



3.12 OMC & MDD Different determinations of OMC & MDD by different laboratories will give rise to a spread of results (Variation). To limit the effect of this variation on the CBR testing in this proficiency program the OMC & MDD have been predetermined. This information was supplied to participants (See instructions Appendix A) so that all participants used the same OMC & MDD values.

3.13 CBR Compaction The revised CBR test method defined the compaction process such that only one approach is now acceptable. It also defined the pattern of compaction blows. If this was not a laboratories normal approach then each staff member should have been given training in those techniques new to them. All participants reported using standard compaction as required by the program and manual compaction. The test method does not specifically state that the numbers of blows are to be recorded. Recoding the blows should be undertaken as it is both a test variable and a measurement that affects the test outcome. It also provides additional information when checking. It is expected that by compacting a calculated amount of material to a set height that the desired density will be achieved. The blows will vary depending on the material type and moisture. Depending on how this is done a variation in the number of blows per layer is the typical outcome. However between layers these should remain reasonably close. Some participants had variation in layer blows of around 20. This could result in density graduation even though the overall density may have been achieved. (J8 – 62/55/40, L5 – 95/75/60 and Y6 – 18/55/55) The range of blows per layer from one participant to another was large. (L6 used 25 blows while L5 used around 80 blows per layer. A variation of nearly 55 blows would seem very strange when everyone starts with essentially the same mass of material for each layer. A number of participants (seven) reported that 53 blows per layer were used. Care needs to be taken to ensure that compaction is to the new test method and not to the previous CBR test method. Overall based on the blows reported in this program most participants should review the compaction technique used to ensure compliance.

3.14 LDR and LMR Calculation of LDR & LMR Participants were requested to submit:

• The sample moisture immediately prior to compaction (w1) in accordance with

clause 6(c) of the standard.



• Moisture content variation (wv)

• The Laboratory Moisture Ratio (LMR)

• The Laboratory Density Ratio (LDR) and

• Dry Density (before soaking) The reported LDR and LMR values were re-calculated using the reported moisture from clause 6(c) and density (before soaking). Those participants that reported starting moisture (i.e. moisture in sample as received) could not be checked. There were a number of participants that had difficulty in calculating these values. The participants listed in Table 3.14A showed inconsistencies in the values submitted and it may assist in improving the quality of testing to review these values.

Table 3.14A: Participants with inconsistencies in calculating LMR and LDR

Achievement of OMC & MDD Participants were requested to compact the sample to 100 % standard compaction.

OMC Moisture Range LMR Range Review

8.3 %

93%

8.9 % -

9.4 %

106 %

MDD Density Range LDR Range Review

2.181

99 %

2.203 t/m3

A4, Z6

2.225

101 %

Table 3.14B: Participants that are outside the limits set for LMR and LDR.

Issues related to Information submitted Review

Moisture (Clause 6c) and variation Z6, L6, M6, F3

Reported LMR does not match reported moisture. Z6, C2, L6, L7, Y2, J7, F3

Reported LDR does not match reported dry density Z6, J7, V5



Overall most participants achieved the desired range for OMC and MDD which was a very good outcome. Participants with results outside these limits as detailed in Table 3.14B may find it helpful to review the results obtained.

3.15 Load & Penetration (Zero Correction) A number of aspects related to testing practice and equipment used were reviewed. It is important that the performance characteristics of the CBR system setup will deliver the accuracy needed for the particular material under test. Load Cell The majority of participants in this program used load cells with five participants (S5, Y4, C2, U4, Y6) using load rings. One load cell was calibrated to ‘Class C’ with the rest calibrated to Class ‘A’ or a combination e.g. A/B/C. Most participants used a 50kN load device except for Q4, E9 used 40kN, V5 used 30kN, S4 used 45kN, and K4 used 100kN. All systems in use appeared satisfactory and there was no observable correlation with the CBR results obtained. Participant V5 was unable to complete the test due to insufficient capacity of the load ring selected. An important consideration is the resolution at the lower end of the load scale in order to accurately measure the seating load. For load cells used in this program that are on the larger side (e.g. 50kN) it may be difficult to accurately measure small loads. Often this is not a lack in ability of the load cell but a reflection of the normal calibration practise where the calibration may not extend to the low load values required for seating loads. Laboratories may need to request calibration facilities, where possible, to specifically cover the seating loads required when undertaking the load cell calibration. Seating Load The standard requires that the least amount of force be used for the seating load. Faced with an unknown sample a seating load of around 50 N should be used unless a participant was confident that the CBR value would be higher than 30 in which case a seating load of 250 N could be used. Many participants expected a CBR greater than 80% for the material supplied and used a seating load of 250 N. Overall there was a wide spread in the magnitude of the seating load used. It is important that the piston is in contact with a stable surface. The seating load is considered the ‘zero point’ from which the load values and penetration commence. At high CBRs the seating load has little effect on the CBR obtained but does influence the penetration. Any effect of incorrect assignment of the zero penetration is usually cancelled out with the zero point correction offset if performed correctly.



However errors in both processes (zero reset and offset correction) will affect the CBR outcome. For this program a 0.5mm error translates to around 10 to 15 % CBR. Inaccurate or varied assignment of the ‘zero point’ may contribute to the variation in CBR results. See zero point correction below for more details. Zero Point Correction Overall the majority of participants correctly accessed the zero point correction and applied it. Seating load and zero correction combined generally result in small changes. However sometimes small changes can have a significant effect and particularly when a BR value is to be rounded either up or down to the nearest 10%. A variation of ± 20 % is not unrealistic. Not applying the zero point correction does have a significant impact. One participant (Q4) did not correct the raw data back to a zero point. Participant (L5) appears to have overestimated the correction needed. Participants Q4 and L5 data have been re-graphed below and the bearing ratio at 5 mm recalculated.

y = 4.517x4 - 161.44x3 + 1795.1x2 - 597.55x + 162.86 R² = 0.9998

02,0004,0006,0008,000

10,00012,00014,00016,00018,00020,00022,00024,00026,00028,00030,00032,00034,00036,00038,00040,00042,00044,000

0 1 2 3 4 5 6 7 8 9 10 11 12

Appl

ied

Load

(N)

Penetration (mm)

CBR Graph for Participant Q4

Data Values

Poly. (Data Values)

Correction

Participant Q4 Submitted Values Recalculated values

Zero correction (mm) 0 1.3

Unrounded CBR (%) 124.2 161.5



Similarly for participant L5.

There is a significant difference in the CBR result obtained. In addition both Q4 and L5 test results are in the middle 50% group of results and did not show as an outlier even when the set ‘SD Limit ‘was applied. Q4 showed a difference of 37% (i.e. from 124 to 161) and is still able to stay in the middle 50%. The reason is the spread of these “Satisfactory” test results is too large. It highlights the need for the middle group of participants to review their results as much as those at the upper and lower edges. Overall every participant should revisit the graphing technique employed. Applied Load All participants reported the applied load values obtained in N as requested with four in kN. Participants C2, V5, S4 and Y6 appear to have reported deflection units. The ‘zero penetration’ load value should either be the seating load used or if the recording system was reset then a zero load. All participants reported that the seating load was set to zero except for participant Z2.

y = 8.0366x4 - 203.31x3 + 1614.8x2 + 1214.8x - 187.74 R² = 0.9998

02,0004,0006,0008,000

10,00012,00014,00016,00018,00020,00022,00024,00026,00028,00030,00032,00034,00036,00038,00040,00042,00044,000

0 1 2 3 4 5 6 7 8 9 10 11 12

Appl

ied

Load

(N)

Penetration (mm)

CBR Graph for Participant L5

Data Values

Poly. (Data Values)

Correction

Participant L5 Submitted Values Recalculated values

Zero correction (mm) 1.2 0.9

Unrounded CBR (%) 166.7 156.7



If the load at 0.5 mm penetration is less than the seating load it may indicate that correct seating and hence the correct zero point was not obtained. Some participants (A4, J7) had a low results compared to others at 0.5 mm penetration. This may indicate incomplete seating. Penetration Rate All participants reported a penetration rate within the Australian Standard specified range of 1 ± 0.2 mm/min. A motorised platform was used by the majority of participants with four participants (S4, L5, Y2, E9) using a hand operated unit. Many participants appear to have quoted the test method requirements rather than stating actual penetration rate. Automated systems often record the penetration rate with a number of participants giving this value. The penetration rate is directly linked to the slope of the force/penetration curve. It is therefore significant in determining the CBR and hence the tight requirements on the rate of travel. A load cell or ring may compress around 0.4mm under high loads. NATA requires checks to be performed at both high and low CBRs. Participants should have submitted penetration rates if recorded or the appropriate determination made under the NATA specified checks. These checks ensure the system can accommodate both the cell/ring deflection as well as the speed of penetration while under load. A 0.25mm shift in the curve could make up to a difference of 5% in the CBR value obtained. This will be more clearly specified in future programs. Selected Penetration Load Values The number of penetration points selected is extremely important. Many laboratories recorded the requested additional load/penetration data. A few took less than that requested for this proficiency program or terminated the test before 12.5mm. The test method specifies a minimum data set (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 7.5, 10.0 and 12.5 mm penetrations). The key word in the test method is “at least”. In other words if you know the material well (i.e. have a CBR history of the material) then you should be able to use fewer points otherwise you need to use more points. Additional points are needed to: Allow for the discount of an abnormal data value Have sufficient points left so that the discounting of a point does not compromise the

test result Have sufficient points to fit a straight line Have sufficient points above the curve section of the graph. Have sufficient points to be able to tell that you have an abnormal data point



Participant U4 was selected at random for this example but there were many other participants’ with small data sets. The penetration/load values submitted for participant U4 were used to produce a graph and a zero correction line. The results are shown below.

Only the minimum data points have been collected. The graph shows that there are some data points that are slightly away from the best fit line (i.e. circled data in the graph above). If more points had been taken then the certainty of these points would not be in doubt. Moving the data points closer to the bests fit line changes the CBR value by around 4 to 8%. A number of other participant’s results were checked by reducing the data down to the minimum set. A similar variation also occurred. It is evident that two few data points can have a measurable difference on the result that is obtained. Greater confidence in the result is obtained when more points are taken.

3.16 Graphing There have been sufficient inaccuracies with graphing technique observed which have an effect on the test variation to warrant their review in a proficiency program. The accuracy of the graph is affected by many of the matters discussed above e.g. seating load, number of data points etc. The zero correction line needs to lie parallel to the straight part of the graph etc. Regardless of what is submitted to the client graphing is important in determining the zero point correction and in both obtaining and checking the results in many cases. Appendix C provides some feedback regarding graphs for this program. They were assessed using two approaches. One assumed that CBR was to be measured from the graph and the second based on the end user’s needs. The feedback should be

y = 9.7711x4 - 267.8x3 + 2180.6x2 - 523.67x + 14.124 R² = 0.9984

02,0004,0006,0008,000

10,00012,00014,00016,00018,00020,00022,00024,00026,00028,00030,00032,00034,00036,00038,00040,00042,00044,000

0 1 2 3 4 5 6 7 8 9 10 11 12

Appl

ied

Load

(N)

Penetration (mm)

CBR Graph for Participant U4

Data Values

Poly. (Data Values)

Correction



taken as an opportunity to improve. We do not know your clients’ needs and we can only base comment on what was submitted. In the end each participant needs to assess the relevance to them of the comments made. Please note that graph feedback is general and has not considered or calculated the effect of seating loads, scales used etc. Graphing can have a large impact on the variation of results observed. Overall graphing has improved vastly over the last six years but there is still room for improvement.

3.17 Reporting CBR The reason for rounding is not entirely clear in the Australian Standard. It perhaps acknowledges that CBR values are quite variable and rounding makes the results easier to use and compare when grouped together i.e. takes out some of the fluctuation. Laboratories were asked for the unrounded Bearing Ratio rather than rounded CBR results. Part of the design consideration of this program was to try and isolate as well as minimise sources of variation. The process of ‘rounding’ was identified as adding to the variation of determining CBR. The statistics associated and test variation with the CBR results will increase slightly if rounded results are used.



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A4 130 -0.35 V9Z6 140.0 0.00 S4 139.0 -0.04Q9 190 1.75 F3 141.8 0.06S5 135.4 -0.16 K4 164.4 0.86Y4 142.1 0.07 Z2 169.4 1.03C2 182.7 1.50L6 114.7 -0.89Q4 124.2 -0.55J8 180 1.40L7 177.2 1.31G4 232.0 3.23 #L5 166.7 0.94Y2 116.8 -0.81E9 115.8 -0.85Y7 136.4 -0.13Z4 110 -1.05A2 110 -1.05U6 150 0.35P3 178.0 1.33L9 156.6 0.58R5 161.6 0.76M6 140.0 0.00U4 156.6 0.58K2 132.6 -0.26J7 110 -1.05V5Y6 137.8 -0.08B2 114.2 -0.91

Number of results 31Median 140.0Median MU 6.40First Quartile 127.1Third Quartile 165.6IQR 38.5Normalised IQR 28.5CV (%) 20.4Minimum 110.0 (110.0)Maximum 190.0 (232.0)Range 80.0 (122.0)

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.

4.1 CBR: Z - Scores

CodeTest

Result %

Z Score CodeTest

Result %

Z Score

Statistic Value



Review Weak Consensus

Weak Consensus Review

4.1 CBR: Z - Score Graph

Strong Consensus

Z4

A2

J7

B2

L6

E9

Y2

Q4

A4

K2

S5

Y7

Y6

S4

Z6

M6

F3

Y4

U6

L9

U4

K4

L5

Z2

L7

P3

J8

C2

Q9

G4

-3 -2 -1 0 1 2 3

Z - Score

R5



A4 130 -0.75 V9Z6 140.0 0.00 S4 139.0 -0.08Q9 190 3.76 # F3 141.8 0.14S5 135.4 -0.35 K4 164.4 1.83Y4 142.1 0.16 Z2 169.4 2.21C2 182.7 3.21 #L6 114.7 -1.90Q4 124.2 -1.19J8 180 3.01 #L7 177.2 2.80G4 232.0 6.92 #L5 166.7 2.01Y2 116.8 -1.74E9 115.8 -1.82Y7 136.4 -0.27Z4 110 -2.26A2 110 -2.26U6 150 0.75P3 178.0 2.86L9 156.6 1.25R5 161.6 1.62M6 140.0 0.00U4 156.6 1.25K2 132.6 -0.56J7 110 -2.26V5Y6 137.8 -0.17B2 114.2 -1.94

Number of results 31Median 140.0Median MU 2.99First Quartile 127.1Third Quartile 165.6IQR 38.5Set SD Limit 13.3CV (%) 9.5Minimum 110.0 (110.0)Maximum 232.0 (232.0)Range 122.0 (122.0)

Note: A # indicates an outlier where the z-score obtained is either greater then 3 or less than -3. These are not considerd outliers but it may be benificial to review these results. 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 z-scores great than 3 or less than -3 excluded, those in brackets include outliers.

4.2 CBR - Set SD Limits: Z - Scores

CodeTest

Result %

Z Score CodeTest

Result %

Z Score

Statistic Value



4.2 CBR - Set SD Limits: Z - Score Graph

Strong Consensus Weak ConsensusWeak Consensus

Z4

A2

J7

B2

L6

E9

Y2

Q4

A4

K2

S5

Y7

Y6

S4

Z6

M6

F3

Y4

U6

L9

U4

K4

L5

Z2

L7

P3

G4

-3 -2 -1 0 1 2 3

Z - Score

Q9

C2

J8

R5



5. Program Details

5.1. Program Design Design This program is one of a series of CBR programs conducted by LabSmart Services over the last ten years. Proficiency testing programs have shown that the CBR test produces a wide variation in results. 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. 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. Selection of Soil Used in the Program The test in this proficiency program is operator skill/experience dependant. Different materials are selected for each program to mirror the range of materials encountered in practice and hence the results obtained. This program provides a sample that gives results in the range that would be commonly tested by laboratories. The higher the CBR value the greater variation encountered. The previous program provided a medium CBR. The material in this program gives a large CBR value. Comments under “Comparing Statistics” should be considered. 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. New Test Method Testing in this proficiency program is to the recently revised AS1289.6.1.1 (November 2014) test method. The changes in the test method have resulted in significant changes to the design of this program compared to previous programs as well as what feedback is possible at this time. The impacts to testing are further discussed under ‘Technical Comment’, section 3. OMC & MDD The determination of OMC and MDD is usually an initial stage undertaken prior to performing a CBR. The determination of these two parameters can show a significant variation which in turn affects the variation obtained for CBR results.



The intention of the program is minimise any influence on the CBR results that could arise from laboratories determining these values in-house and reduce the likelihood of different OMC and MDD values being applied. To assist in reducing this variation, participants were requested to use 100% standard compaction and use:

• OMC = 8.9%

• MDD = 2.203 t/m3. Although this has been the approach to try and minimise variation other aspect may still contribute to the variation observed. OMC/MDD values may vary from person to person but this may not be so important if the same person determines OMC/MDD and CBR. That is a low compaction on the OMC/MDD should give the same compaction on the CBR. Overall it is still considered that a set OMC/MDD will provide the least variation. 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. Next to measurement uncertainty it is the next most useful tool a laboratory has in better understanding the performance of a test. Participant Assessment Assessment of each participant is based on a z-score that is related to the program consensus value (median) and compliance to proficiency testing program requirements including the correct calculation of results. Z-Scores Summary A “Z-Scores Summary” is issued soon after the majority of results are received to provide early reporting of outliers. This gives participants early feedback as to any program outliers. The summary is available on the LabSmart Services website up until the final report is issued. The final report contains detailed technical feedback regarding the performance of tests. 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 and test method accuracy 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 10 % means that any number between 45 and 55 will become 50%. If the largest value is 45 in a set of results it is pushed out to 50 through rounding. Rounded results may better reflect the repeatability and reproducibility of the test according to the rounding in the test method but are not as useful when considering laboratory performance. 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. Additional Information Requested This program requested additional information as detailed in Section 6 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.

5.2. Sample Preparation Sufficient soil of a homogeneous appearance was obtained for the proficiency program. The lot was partially dried then mixed to ensure, as far as possible, a homogeneous material throughout. The material was sampled and placed into numbered plastic bags. Ten samples were drawn at regular intervals from the lot for homogeneity testing. Each participant received a randomly drawn sample from the remaining samples. A randomly generated unique program code was assigned to each sample.

5.3. Packaging and Instructions The plastic bags were sealed with a rubber band and placed into a sturdy box. Each participant received one box with a sealed sample labelled ‘CBR Sample’. The sample weighed approximately 8.5 kg. Instructions and a ‘results log’ sheet were enclosed. (See Appendix A & B) Participants were instructed to test according to the nominated test method and report to the accuracy indicated on the ‘Results Log’.



5.4. Quarantine There were no samples that required additional preparation in order to meet quarantine requirements.

5.5. Sample Despatch Samples were dispatched to participants on the 5 June 2015 via courier. Dispatched samples were tracked from ‘despatch to delivery’ for each participant.

5.6. Homogeneity Testing Samples for homogeneity testing were packed in the same way as those for all participants. The homogeneity samples were tested by an independent NATA accredited laboratory. To approximate the same conditions the same instructions were given to the laboratory performing the homogeneity testing. Ten samples were tested for homogeneity. Two of the samples gave results that were significantly higher and lower than the remaining group of eight results. Removal of these improved the statistics significantly. However the removal of these two results could not be substantiated on a statistical level and as a consequence have been left in. The wide variation in results that affects CBR testing can also affects homogeneity testing particularly at high CBRs. However the overall variability associated with the proficiency samples was still considered satisfactory. This provides confidence that any outliers identified in the program represent statistically valid outliers. A statistical analysis of the homogeneity testing results is provided in table 5.1.

5.7. Participation Thirty-two participants from around Australia entered the program. Thirty-one participants returned results. Participants were requested to return results by 10 July 2015.

5.8. 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.



Code

Bearing Ratio

CBR Rounded CBR 2.5 mm 5.0 mm

% %

H1 149.3 189.7 189.7 190

H2 190.4 214.2 214.2 210

H3 131.3 172.6 172.6 170

H4 133.1 168.4 168.4 170

H5 142.3 184.1 184.1 180

H6 147.9 183.8 183.8 180

H7 123.8 146.0 146.0 150

H8 167.7 200.7 200.7 200

H9 128.3 168.6 168.6 170

H10 165.5 202.6 202.6 200

Mean 148.0 183.1 183.1 182

Standard Deviation 21.08 20.04 20.04 18

Range 66.6 68.2 68.2 60

Coefficient of Variation (%) 14.2 10.9 10.9 10

Table 5.1 Homogeneity results.

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. Assessment of participants data is undertaken to ensure data is statistically comparable. Checks are undertaken to ensure the data calculated matches that reported by the participant and that the appropriate corrections etc. have been applied if required. The level of checking required varies from program to program. If inconsistencies are identified the data may be removed or amended with the discrepancy highlighted. 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 are an approximate of the standard deviation. 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 results 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. Comparing statistics from one proficiency testing 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.

The results represent a ‘snap shot’ of the competency within the industry and hence provide an overview of the industry as a whole. The more participants involved in the program then generally the more representative the overview. 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.



Code A4 Z6 Q9 S5 Y4 C2 L6

Mass Retained on 19 mm sieve (%) 0.0 Nil 0 0 0 0.15 1Moisture-Before compaction, Cl 6(c) (%) 8.8 7.0 8.6 8.8 9.0 8.8 8.8Moisture Content Variation (Wv) (%) -0.1 0.5 0.3 -0.1 0.1 -0.1 6.6Compaction (Manual or Auto) M M M M M M MCompaction Method Standard (Y/N) Y Y Y Y Y Y YNo. blows/ layer 49/49/49 53/53/53 45/45/45 53/44/44 53/53/40 48/48/48 25/25/25Dry Density g/cm3 2.231 2.189 2.210 2.202 2.200 2.206 2.203Density Ratio (LDR) % 101.3 2.189 100.3 100.0 99.9 100.1 99.8Moisture Ratio (LMR) % 98.9 8.4 96.6 98.9 101.1 0.8 100.0BR @ 2.5 mm (%) 90 120.0 150 108.9 114.5 164.7 90.2BR @ 5.0 mm (%) 130 140.0 190 135.4 142.1 182.7 114.7CBR (%) 130 140.0 190 135.4 142.1 182.7 114.7Correction (mm) 1.6 0.7 0.5 0.75 0.75 0.6 0Swell (%) -0.31 Nil 0.0 -0.1% -0.1% 0 0.1Moisture ww 8.9 8.4 8.6 9.8 10.0 10.0 9.2Moisture w30 9.0 9.9 8.7 8.8 9.0 10.5 9.3Moisture wr 8.8 NR 8.6 8.5 8.5 10.0 8.8Date last calibrated 5/3/2014 7/07/2015 11/09/2014 22/07/2014 22/07/2014 6/08/2013 16/01/2014Calibrated range 0.0-50Kn 0.0-50Kn 0-50KN 0-50kN 0-50kN 0.5-50kN 0.001-50kNLoad cell (C) or ring (R) C C C R R R CCalibration Class (A, B, C) A NR C,B,A,AA A A A AHand driven (H) or motorised (M) M M M M M M MRate of penetration (mm/min) 5mm/5min 1.0+-0.2 1.00/min 1mm/min 1mm/min 1.025 1+_2Seating load applied (N) 48N 0.003 kN 250N 250N 250N 23 156NSeating load set to zero (Y/N) Y Y Y Y Y Y YPeriod Cured (hours) 96 48 48 96 96 72 48Graph computer or hand (C/H) H H C C C C CCondition of material wet/segregated Sealed Good Satisfactory Satisfactory Standard SealedLoads in ( N or kN ) N kN N kN kN Delfection N

0 0 0 0.00 0.0 0.0 0 00.5 100 0.791 1170 0.712 0.970 250 20241 538 2.821 4060 2.156 2.568 640 4278

1.5 1410 5.413 8010 4.115 4.940 1086 68042 2700 8.303 12410 7.054 7.570 1184 9198

2.5 4320 11.224 16530 10.199 10.457 1228 119023 6380 14.191 20130 13.139 13.551 1272 14147

3.5 8450 17.009 23820 15.614 16.696 1319 163394 10800 19.998 27490 18.295 19.326 1360 18501

4.5 13250 22.527 30750 20.976 21.801 1399 206695 16700 24.920 34210 23.090 24.173 1440 227076 22500 29.560 40350 27.937 29.432 1520 26992

7.5 30900 35.002 48970 34.228 35.775 NR 306098 33700 37.003 NR 35.981 37.734 NR 3461110 44300 44.497 NR 41.704 43.148 NR 41067

10 512.5 NR 53.813 NR 46.500 50.367 NR 49707

Code A4 Z6 Q9 S5 Y4 C2 L6Number 1 2 3 4 5 6 7

Notes: (1) NR = No result returned

6.0 - Particpants Test Results



Code Q4 J8 L7 G4 L5 Y2 E9

Mass Retained on 19 mm sieve (%) 0 0 0 0.1 0 0 0Moisture-Before compaction, Cl 6(c) (%) 8.8 9.0 8.4 8.7 9.0 9.3 8.8Moisture Content Variation (Wv) (%) 0.1 -0.1 0.5 0.2 0.1 0.4 0.1Compaction (Manual or Auto) M M M M M M MCompaction Method Standard (Y/N) Y Y Y Y Y Y YNo. blows/ layer 50/50/50 62/55/40 55/40/40 30/30/28 95/75/60 55/50/50 53/53/53Dry Density g/cm3 2.205 2.201 2.215 2.207 2.200 2.204 2.200Density Ratio (LDR) % 100.1 99.9 100.5 100.2 99.9 100.0 99.9Moisture Ratio (LMR) % 98.9 101 94.9 97.8 101.1 94.4 98.9BR @ 2.5 mm (%) 56.4 140 153.8 197.0 132.1 94.2 92.7BR @ 5.0 mm (%) 124.2 180 177.2 232.0 166.7 116.8 115.8CBR (%) 124.2 180 177.2 232.0 166.7 116.8 115.8Correction (mm) 0 0.7 0.6 0.8 1.2 0.0 0.8Swell (%) 0.0 -1.4 -0.2 0.0 -0.3 -0.1 0.0Moisture ww 9.2 9.9 9.1 9.4 10.1 9.5 9.9Moisture w30 7.9 8.5 9.0 9.9 8.6 9.0 9.0Moisture wr NR 8.6 NR 9.4 8.6 8.8 9.0Date last calibrated 25/07/2015 6/05/2014 9/06/2015 10/09/2014 4/02/2015 20/10/2014 31/10/2014Calibrated range 0-40kN 0.001-50kN 0-50kN 50kN 0-50kN 0-50kN 0-40kNLoad cell (C) or ring (R) C C C C C C CCalibration Class (A, B, C) A A A A A A AHand driven (H) or motorised (M) M M M M H H HRate of penetration (mm/min) 1.0mm/min 0.99 1.1 1mm/min 1mm/min 1.0mm/min 1mm/minSeating load applied (N) 250N 250 60N NR 250N 40 40NSeating load set to zero (Y/N) Y Y Y Y Y Y YPeriod Cured (hours) 48 48 48 48 48 50 141Graph computer or hand (C/H) C C H H C C CCondition of material Sealed Good Satisfactory Moist Good Good GoodLoads in ( N or kN ) N N N N N N N

0 0 0 60 0 NR 0 00.5 599 1477 1430 970 700 345 4091 1297 3545 4410 3200 2140 5687 1993

1.5 2518 6248 8310 6700 4490 8138 40202 4827 9399 12140 11700 7410 10248 6234

2.5 7443 12817 16320 17200 10210 12435 86343 10784 16447 19730 22200 13400 14523 10983

3.5 13890 NR 23050 26800 16400 16773 134304 17296 23673 26040 31300 19500 18694 15870

4.5 20960 NR 29080 35900 22700 21061 179805 24600 30535 32000 40000 25400 23118 204106 32220 NR 37690 48000 31900 27280 23730

7.5 NR 45294 45080 NR 39800 32528 294308 NR NR 47630 NR 41400 34361 3182010 NR 59083 NR NR 50500 40583 38930

10 512.5 NR 70401 NR NR NR 47863 NR

Code Q4 J8 L7 G4 L5 Y2 E9Number 8 9 10 11 12 13 14





Code Y7 Z4 A2 U6 P3 L9 R5

Mass Retained on 19 mm sieve (%) 0 0 0 0 0 0 0Moisture-Before compaction, Cl 6(c) (%) 9.1 8.9 8.9 8.9 8.8 8.8 8.8Moisture Content Variation (Wv) (%) 0.2 0.1 0.0 0.0 0.1 0.1 0.1Compaction (Manual or Auto) M M M M M M MCompaction Method Standard (Y/N) Y Y Y Y Y Y YNo. blows/ layer 33/35/21 0/5/3 30/30/30 30/30/31 53/53/53 43/43/53 53/53/47Dry Density g/cm3 2.207 2.203 2.214 2.198 2.203 2.180 2.216Density Ratio (LDR) % 100.2 100 100.5 99.8 100.0 99.0 100.6Moisture Ratio (LMR) % 102.2 100.5 100.0 100.0 98.9 98.9 98.9BR @ 2.5 mm (%) 102.3 90 80 120 128.1 137.9 141.7BR @ 5.0 mm (%) 136.4 110 110.0 150 178.0 156.6 161.6CBR (%) 136.4 110 110.0 150 178.0 156.6 161.6Correction (mm) 0.8 0 0.7 0.3 0.0 0.8 0.8Swell (%) -0.4 0.0 -0.1 -0.1 -0.1 -0.21 -0.1Moisture ww 10.2 9.2 9.8 9.8 10.3 9.6 10.1Moisture w30 8.2 8.4 10.4 9.3 8.3 9.0 8.6Moisture wr 8.4 8.3 9.3 9.1 8.7 8.9 8.8Date last calibrated 26/05/2014 17/06/2015 4/03/2015 17/03/2014 10/10/2013 10/09/2014 11/07/2013Calibrated range NR 0-50kN 0-50kN 0-50kN 0-50kN 0-50kN 0-50kNLoad cell (C) or ring (R) C C C C C C CCalibration Class (A, B, C) A A A A A A AHand driven (H) or motorised (M) M M M M M M MRate of penetration (mm/min) 1mm/min 1.0mm/min 0.88 1.048 1.0mm/min 1.0mm/min 1.0mm/minSeating load applied (N) 50 250 250N 50N 240 250kN 250NSeating load set to zero (Y/N) Y Y Y Y Y Y YPeriod Cured (hours) 75 48 48 48 48 48 48Graph computer or hand (C/H) NR NR H C C C CCondition of material NR OK Moist Good Moist Dry MoistLoads in ( N or kN ) N N N N N N N

0 0 0 0 50 0 0 00.5 460 1500 690 1665 3566 533 16501 1766 3976 2271 5760 6699 2145 3329

1.5 3789 6479 4073 9474 10063 5263 63502 6250 8655 5896 12307 13634 9190 9806

2.5 8979 10617 7958 14377 16908 13138 131503 11734 12636 10048 16697 20392 16622 16950

3.5 14389 14679 12284 18889 24424 19422 200504 16954 16465 14434 21390 28087 22089 23371

4.5 19732 18227 16345 24749 31644 24923 262535 22587 20259 18394 27688 35239 27486 287186 27863 24067 22550 32333 41491 31739 33045

7.5 35814 29354 28356 37890 50269 37496 395058 38158 30981 30343 40271 NR 39247 4142010 48084 37112 36307 52370 NR 45002 48850

10 512.5 NR 44463 44506 NR NR NR NR

Code Y7 Z4 A2 U6 P3 L9 R5Number 15 16 17 18 19 20 21





Code M6 U4 K2 J7 V5 Y6 B2 S4

Mass Retained on 19 mm sieve (%) 0 0 0 0 0 0 0Moisture-Before compaction, Cl 6(c) (%) 8.9 8.8 8.8 8.6 8.8 8.4 8.9Moisture Content Variation (Wv) (%) 100.0 0.1 0.1 0.3 0.1 0.5 0Compaction (Manual or Auto) M M M M M M MCompaction Method Standard (Y/N) Y Y Y Y Y Y SNo. blows/ layer 53/53/53 53/53/53 48/45/53 53/49/50 53/53/53 18/55/55 53Dry Density g/cm3 2.203 2.203 2.203 2.203 2.209 2.209 2.220Density Ratio (LDR) % 100.0 100.0 100 100.5 100 100.3 100.8Moisture Ratio (LMR) % 100.0 98.9 99 96.0 99 94.4 100.5BR @ 2.5 mm (%) 110.0 136.6 101.4 80.0 140 101.7 64.3BR @ 5.0 mm (%) 140.0 156.6 132.6 110.0 NR 137.8 114.2CBR (%) 140.0 156.6 132.6 110.0 NR 137.8 114.2Correction (mm) 1.5 1.5 0.8 1.4 0.6 0 0Swell (%) -0.1 0.0 0.0 0.1 -0.1 -0.1 0Moisture ww 9.7 8.9 9.5 10.0 10.0 NR 10.7Moisture w30 9.1 9.2 8.8 8.6 8.6 9.2 8.9Moisture wr 8.9 9.0 8.2 8.5 8.7 8.5 9.2Date last calibrated 17/04/2015 6/11/2013 23/04/2014 9/08/2013 19/09/2015 3/06/2013 23/08/2013Calibrated range 0-50kN 0-50kN 0-50kN 0-50kN 0-30kN 5-50kN 0-50kNLoad cell (C) or ring (R) cc508c R C C C R CCalibration Class (A, B, C) A A A A A A ABCHand driven (H) or motorised (M) M M M M M M MRate of penetration (mm/min) 0.88 1.0 0.86 1 mm/min 1.02 1 mm/min 0.806-1.20Seating load applied (N) 240 250 0.250 250kN 245N NR 250NSeating load set to zero (Y/N) Y Y Y Y Y Y YPeriod Cured (hours) 48 48 49 72+ 50 96 96Graph computer or hand (C/H) C C C NR C H CCondition of material Moist Moist Moist Dry Moist Good In plastic bagLoads in ( N or kN ) N N N N Delfection Delfection kN

0 0 0 0 0 0 0 00.5 677 894 979 221 62 1 1.1981 1970 1281 2405 778 179 13 2.668

1.5 3685 2866 4200 1940 353 58 4.3392 5672 4558 6563 3542 549 115 6.293

2.5 7951 8623 9254 5441 737 170 8.4943 9973 12408 11889 7559 920 233 10.692

3.5 12418 NR 14591 9832 1099 285 13.8434 14703 18225 17241 11991 1272 342 17.298

4.5 17470 NR 19889 13847 1440 405 20.2345 20328 25439 22588 16095 NR 468 22.6146 26032 NR 27570 20433 NR 582 26.832

7.5 34340 35365 34327 25977 NR 727 33.0418 36584 NR 36669 27960 NR 775 35.38610 46509 43470 45215 34844 NR 953 43.024

10 512.5 NR 49540 >50000 41231 NR 1168 49.310Code M6 U4 K2 J7 V5 Y6 B2

Number 22 23 24 25 26 27 28





Code V9 S4 F3 K4 Z2

Mass Retained on 19 mm sieve (%) NR 0 1 0 1Moisture-Before compaction, Cl 6(c) (%) NR 8.8 6.0 8.8 8.8Moisture Content Variation (Wv) (%) NR -0.1 2.9 -0.1 0.1Compaction (Manual or Auto) NR M M M MCompaction Method Standard (Y/N) NR Y Y Y YNo. blows/ layer NR 30/30/30 39/39/39 53/53/53 52/52/45Dry Density g/cm3 NR 2.200 2.203 2.213 2.204Density Ratio (LDR) % NR 99.9 100.0 100.5 100.0Moisture Ratio (LMR) % NR 98.9 100.0 98.9 98.9BR @ 2.5 mm (%) NR 103.7 110.5 136.8 143.4BR @ 5.0 mm (%) NR 139.0 141.8 164.4 169.4CBR (%) NR 139.0 141.8 164.4 169.4Correction (mm) NR 0.4 0.1mm 0.6 0.2Swell (%) NR 0 -0.1mm 0.0 0.0Moisture ww NR 8.8 8.5 9.0 9.6Moisture w30 NR 9.4 9.2 8.9 10.0Moisture wr NR 9.0 100.0 8.7 9.2Date last calibrated NR 08/2-13 15/10/2014 13/11/2014 19/07/2013Calibrated range NR 0-45kN 0-50kN 0-100kN 0-50kNLoad cell (C) or ring (R) NR R C C CCalibration Class (A, B, C) NR A NR A CHand driven (H) or motorised (M) NR H M M MRate of penetration (mm/min) NR 1mm/min 1mm/min 1mm/min 1mm/minSeating load applied (N) NR 0.1 232 250N 255Seating load set to zero (Y/N) NR Y Y Y NPeriod Cured (hours) NR 48 48 96 48.5Graph computer or hand (C/H) NR C C C CCondition of material NR NR Good Suitable NRLoads in ( N or kN ) NR Delfection N N N

0 NR 0 232 0 NR0.5 NR 47 2312 1792 26231 NR 123 5257 3496 6364

1.5 NR 216 7976 6920 104232 NR 318 11022 10483 14120

2.5 NR 412 13726 14040 174973 NR 512 16839 17685 20814

3.5 NR 626 19532 21190 239114 NR 712 22370 24061 27101

4.5 NR 808 24989 26960 298965 NR 905 27384 29326 324346 NR 1103 32505 34700 37568

7.5 NR 1390 42004 42707 451168 NR 1465 44670 44850 4786810 NR NR NR 54612 NR

10 5 NR12.5 NR NR NR 65329 NR

Code V9 S4 F3 K4 Z2 0 0Number 29 30 31 32 33 34 35





59 App A CBR PT Instructions V1.9

LabSmart Services

Proficiency Testing Program

California Bearing Ratio – 2015 (59)

INSTRUCTIONS FOR TESTER

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

Instructions (for tester) Results Log Approximately 8.5 kg of soil sealed in a plastic bag labelled ‘2015 (59) CBR Sample’

Contact LabSmart Services if the bags are damaged or any item is missing.

2. When can I start testing? As soon as you have read these instructions carefully and

your supervisor has indicated that you may do so.

3. How long do I have to do the testing? You need to have the results back to LabSmart Services by the 10 July 2015.

4. Due to the possibility of segregation during transportation mix the sample thoroughly

prior to testing.

5. Sieve the sample over the 19 mm sieve to determine the amount of oversize present as per the test method. Record this as a % on the results log. Discard the oversize material.

6. You do not need to be accredited for AS 1289 6.1.1 (2014). You may use other

equivalent methods but it is preferable that AS 1289 6.1.1 (2014) be used.

7. Conduct the CBR test to AS 1289 6.1.1 (2014) using the following information. Use an OMC of 8.9 % (see note below). Adjust the moisture of the sample mixing thoroughly at intervals and cure for

at least 48 hours. This should be done in a plastic bag with the end tied/folded over.

As per clause 6(c) of the test method just prior to compaction take a sample to determine final moisture content (w1) has been achieved.

Sample to be remoulded at 100% standard compaction. Use a MDD of 2.203 t/m3 (see note below). Apply a 4.5 kg surcharge. Soak the sample as per the method for 4 days. Swell is to be determined. Take additional load readings at 3.5, 4.5, 6.0 and 8.0 mm penetration.

Note: The test method indicates that the LMR be within 100 ± 1.5% and the LDR be within 100 ± 1%

Page 1 of 2

Appendix A



59 App A CBR PT Instructions V1.9

8. Please study the “Results Log” carefully before beginning the test.

9. Record the results on the enclosed “Results Log”. Report each result according to the log sheet. This will be different to the test method.

10. The Laboratory Manager or person responsible for checking should sign the log sheet

to indicate that it has been checked.

11. Please retain any unused sample until the final report has been issued.

12. Have a query? Contact Peter Young at LabSmart Services. Phone. 0432 767 706

13. Fax or e-mail the “Result Log” to LabSmart Services by 10 July 2015.

Fax: (03) 8888 4987 OR

E-mail: [email protected]

14. Please retain the completed “Results Log” as this contains your confidential participation code. You will need this code to 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.

15. Proficiency testing can also form part of a laboratories training records for the technician who performed the test.

Thank you for participating in this proficiency testing program.

Page 2 of 2



59 App B CBR PT Results Log V1.9

LabSmart Services

Proficiency Testing Program

California Bearing Ratio – 2015 (59)

RESULTS LOG for xxxx

Participation Code: xx

Please fax or e-mail the completed results log by 10 July 2015 E-mail: [email protected] or Fax: (03) 8888 4987

1.

Report To Result Test Method

Used

Tested By: Name

Mass retained on the 19 mm Sieve 1 %

Moisture (Clause 6[c]) (W1) (before compaction)

0.1 %

Moisture content variation (Wv) 0.1 %

Compaction Manual or Auto

Compaction Method Standard (Y/N)

Number of blows used per layer Number

Before Soaking

Dry density 0.001 g/cm3

Density Ratio (LDR) 0.1 %

Moisture Ratio (LMR) 0.1 %

BR @ 2.5 mm 0.1 %

BR @ 5.0 mm 0.1 %

Correction# 0.1 mm

Swell 0.1 %

After soaking

Moisture ww 0.1 %

Moisture w30 0.1 %

Moisture wr 0.1 % # Enter zero if no correction is performed.

Page 1 of 3

Appendix B



mailto:[email protected]

59 App B CBR PT Results Log V1.9

2. Please describe the characteristics of the CBR machine used for the test:

Last date calibrated

Calibrated range (I.e.0-50 kN)

Load Cell or Load Ring?

Calibration (Class A, B, C?)

Hand driven or motorised platform?

Rate of penetration? 3. Please attach worksheet detailing the penetration/load readings recorded

OR Record the penetration/ load readings below (cross out and change if other penetration values are used).

Penetration

(mm) Load (N) Penetration

(mm) Load (N)

0 4.0

0.5 4.5

1.0 5.0

1.5 6.0

2.0 7.5

2.5 8.0

3.0 10.0

3.5 12.5

4. Condition of material as received………………………… Seating load used.....................Has the seating load been set to zero? (Y/N)............. Period cured for? (hours).............

5. Please attach a copy of the CBR graph for the test. COMMENTS: (Please ensure all 5 sections above are completed) …………………………………………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………

------------------------------------ ---------------------------------- --------------- 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 issue of the final technical report covering this program.

Thank you for participating. Please retain these sheets for your records. ________________________________________________________________________

Have a query? Contact Peter on 0432 767 706.

________________________________________________________________________

Page 2 of 2



Based on the end user needs

(1) Graph produced by (2) Scale (3) Accuracy of

graphZero

correction (4) Slope Size Clear (5) Readability Comments

1 A4 Hand OK OK Y OK OK Y Y2 Z6 Hand Load Review Y OK OK Y Y3 Q9 Computer OK OK Y OK OK Y Y4 S5 Hand OK OK Y OK OK Y Y5 Y4 Hand/Computer OK OK Y OK OK Y Y6 C2 Computer NA NA Y Review Small N N Upward spike at 2 mm, slope appears unusual7 L6 Computer NA NA Y OK OK Y Y8 Q4 Computer NA NA Review OK OK Y Y No zero correction done9 J8 Computer NA NA Y OK Small N N10 L7 Hand OK OK Y OK Small Y Y11 G4 Hand OK OK Y OK OK Y Y12 L5 Computer NA Review Review Review Small N N13 Y2 Hand Load Review Y OK Small N N14 E9 Computer Load Review Y OK Small N N15 Y7 - - - - - - - - A graph was not supplied.16 Z4 - - - - - - - - A graph was not supplied.

(3) NA is for "not applicable" and generally applies where the graph is computer generated. The accuracy of reading off the graph was affected by the scaling adopted in some cases. If this is important then particpants shown as 'Review' may considere improving the graph.

Based on the need to measure CBR from graph

Code

(4) The slope can sometimes look different enough to repeat the test. Unfortunately with profciency programs this is not always possble. Particpants should comment when this occurs to say that they would considere the result suspect until further testing was undertaken.

(5) Readability is based on the client being able to read the CBR result off the grapgh. Particiapnts need to determine if this is relavent to them or not.

Appendix C - Graphing Feedback

Notes: (1) Graphs were some times hard to tell if they were hand drawn or computer generated.

(2) Scales were less important on a computer gernerated graph if the calculations were done automatically. Where results had to be read off the grapg then the scale wsa important. Generally penetration scale was fine with some shown as "load " a scale with better resolution might be better.



Based on the end user needs

(1) Graph produced by (2) Scale (3) Accuracy of

graphZero

correction (4) Slope Size Clear (5) Readability Comments

17 A2 Hand Load Review Y OK Small N N18 U6 Computer/hand Load Review Y not OK N N Upward spike at 5 mm, slope appears unusual19 P3 Computer NA NA Y OK OK Y Y20 L9 Hand Load Review Y OK OK Y N21 R5 Computer Load Review Y OK OK N N22 M6 Computer NA OK Y OK OK Y Y23 U4 Computer NA NA Y Review OK Y N Insufficient points from 5mm onwards24 K2 Computer Load NA Y OK OK Y Y25 J7 - - - - - - - - A graph was not supplied.26 V5 Computer Load NA Y OK Small N N Data stops at 4mm27 Y6 Hand OK OK Y OK OK OK Y OK for inhouse use28 B2 Computer NA NA Y OK OK OK Y29 V9 - - - - - - - - No results returned30 S4 - - - - - - - - Faxed graph - unable to read31 F3 Computer Load NA Y OK Small OK Y32 K4 Computer Load NA Y OK Small N N33 Z2 Computer Load NA Y OK Small N N

Notes: (1) Graphs were some times hard to tell if they were hand drawn or computer generated.

(2) Scales were less important on a computer gernerated graph if the calculations were done automatically. Where results had to be read off the grapg then the scale wsa important. Generally penetration scale was fine with some shown as "load " a scale with better resolution might be better.

(3) NA is for "not applicable" and generally applies where the graph is computer generated. The accuracy of reading off the graph was affected by the scaling adopted in some cases. If this is important then particpants shown as 'Review' may considere improving the graph.

(4) The slope can sometimes look different enough to repeat the test. Unfortunately with profciency programs this is not always possble. Particpants should comment when this occurs to say that they would considere the result suspect until further testing was undertaken.

(5) Readability is based on the client being able to read the CBR result off the grapgh. Particiapnts need to determine if this is relavent to them or not.

Appendix C - Graphing Feedback

Code

Based on the need to measure CBR from graph



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