1. Pts feedback - what are the trends telling us… & methods in question
Test & Measurement Conference 2017
Measurement science for
growth in Africa!
St Georges Hotel & Conference Centre
Centurion, Gauteng
Barry Pearce
1st August 2017
A B C or
X Y Z ??

2. Discussion to include…
Intro & general comments
What are the Numbers
Ranges & StDev trends
Asphalt
Granular
Aggregate
Binder
Additional comments
Concluding remarks

3. Intro & General comments
Used StDev & linear trend lines as evaluations tools
StDev a good indicator as it’s a relative result
What are we looking for
a decrease in StDev & dipping trend line (left – right)
Some results may need to be assessed separately
If material type changes
Granular with/without PI
Asphalt WC vs BTB
Require at least 3 sets of results to get a sense of the trend
With more results the trend will become more apparent
Limits can then be more accurately determined
Insufficient results to depict a trend for
Concrete & Spot test
Some additional tests methods have been added along the way resulting in less data for some methods
DSR
Gyratory
Plus others

4. What do the numbers look like? PTS undertaken
Overall todate
2011 – July 2017
20 in total
5 this year
5 rounds for 2017 still to be undertaken
25 by year end
10 for this year
Annual 10 planned

5. What do the numbers look like? By material type
Asphalt 6 (7)
Aggregate 4 (5)
Granular 5 (6)
Bitumen 4 (5)
Concrete 1 (2)

6. What do the numbers look like? Laboratories participating
570 total
2017 – 184 (only ½ way)
Average 28.5/round

7. What do the numbers look like? Average Laboratories participating/round
Good growth shown in 2017
Avg 28.5 participants/round since 2011
2017 average participation = 37/round
Well up on previous years & growing

8. What do the numbers look like? OB’s & % of z-score ±1
Obvious blunders
Minimal since 2016 when OB’s were introduced.
Only applied when plainly obvious its an error.
All other cases included in stats analysis & taken care of by weighted robust stats approach.
% z-scores ±1
On average just < 70 %
Although a fairly high value
Still some errors that could improve this figure.

9. Typical errors encountered
Rule No1 for PTS participation
FOLLOW THE TEST METHOD specified to the letter!!!
Inaccuracies often attributed to this issue
Renders PTS less valuable or results in an OB classification
Transfer errors
Particular in grading results
Do in-depth Trend analysis of your performance
Always above or below average
Always an OB
Difference personals performances monitored
Finally do the same method in your daily routines
Reduced disputes & results in better quality results

10. Asphalt analysis – BD & MVD
BD Standard Deviation
Decreased
27.4 – 12.6 kg/m3
Avg kg/m3
MVD Standard Deviation
Slight increase
11.0 – 5.2 kg/m3
Avg 8.67 kg/m3

11. Asphalt analysis – Stability & Flow
Stability Standard Deviation
Slight increase
2.40 – 1.50 kN
Avg = 1.95 kN
Flow Standard Deviation
Slight decrease
0.82 – 0.50 mm
Avg = 0.62 mm

12. Asphalt analysis – Binder % & Abs
Binder % Standard Deviation
Decrease
0.17 – 0.10 %
Avg = 0.14 %
Binder Abs Standard Deviation
Constant
0.24 – 0.15 %
Avg = 0.20

13. Asphalt analysis – VIM VIM Standard Deviation Decrease 0.93 – 0.60 %
Avg = 0.82 %

14. Asphalt analysis - ITS ITS Standard Deviation Decrease 361 – 128 kPa
Avg = 303 kPa

15. Granular – LL & PL LL Standard Deviation PL Standard Deviation
Increase
11.72 – 0.14 %
Avg = 3.68
PL Standard Deviation
Slight increase
3.0 – 0.1 %
Avg = 1.46 %

16. Granular – MDD & OMC Only based on 3 results MDD Standard Deviation
Decrease
65.7 – 30.0 kg/m3
Avg = kg/m3
OMC Standard Deviation
Increase
0.5 – 0.2 %
Avg = 0.36 %

17. Granular – CBR CBR @ 100, 95, 90 % Standard Deviation 100 % 95 % 90 %
Slight increase
Slight decrease
39.1 – 23.7 %
22.7 – 13.5 %
17.8 – 6.1 %
Avg = 33.2 %
Avg = 15.0 %
Avg = 12.1 %

18. Aggregate analysis – ALD direct & compu
ALD Standard Deviation
Decrease
0.505 – mm
Avg = mm
ALD comp Standard Deviation
Increase
0.757 – mm
Avg = mm

19. Aggregate analysis - FI
FI standard Deviation
Increase
3.194 – %
Avg = %

20. Aggregate analysis - SE
Only based on 3 results
SE standard Deviation
Increase
– %
Avg = %

21. Aggregate analysis – ACV vs 10 % FACT
Only based on 3 results
ACV standard Deviation
Decrease
9,840 – %
Avg = %
10 % FACT standard Deviation
Decrease
95.1 – 24.4 kN
Avg = 66.7 kN

22. Bitumen analysis – Pen vs R&B
Penetration Standard Deviation
Increase
10.16 – 3.90 dmm
Avg = 5.97 dmm
R&B Standard Deviation
Decrease
1.3 – 1.0 oC
Avg = 1.13 oC

23. Bitumen analysis – Viscosity @ 60 & 135 oC
60 oC Standard Deviation
Increase
83 – 31 Pa.s
Avg = Pa.s
135 oC Standard Deviation
Decrease
0.287 – Pa.s
Avg = 0.127Pa.s

24. After RTFOT – Mass Loss vs Viscosity
Mass Loss Standard Deviation
Increase
0.104 – %
Avg = 0.08 %
60 oC Standard Deviation
Increase
106 – 69 Pa.s
Avg = Pa.s

25. After RTFOT – R&B R&B Standard Deviation
Decrease
3.6 – 1.3oC
Avg = 2.02 oC
Increase in R&B Standard Deviation
Decrease
2.9 – 1.0 oC
Avg = 1.58 oC

26. After RTFOT – retained penetration
R&B Standard Deviation
Decrease
14.2 – 10.6 dmm
Avg = dmm

27. Concrete In general a good set of results
Z-score < ±1 just below 70
Standard for other methods
Concerns
One set of results returned with 150 mm cube dimensions filled in
Report results for mass in g not kg
2 436 g vs kg
Rate of compression questionable in some cases.
Crushing time 25 sec for 55 MPa concrete
NB!!!
Carefully check results before submitting!!

28. Test methods with increasing trends
Asphalt
Marshall Stability
Granular
LL, PL, PI
OMC
CBR
slight increase in A & B moulds
Aggregate
ALD FI SE
Bitumen
Penetration
60 oC
Mass loss after RTFOT
14/32 methods (44 %) have increasing trends
There's room for improvement here

29. Additional comments 10 rounds annually Initial draft report Purpose
Check for data transfer errors ONLY
Not allowed to alter values initially submitted
Additional info
Automatic / manual
Proving ring vs load cell
Viscosity info
torque, speed & spindle #
DD of CBR moulds
Duration of sertain activities
Heating asphalt
Crushing cubes
Critical to assist industry in identifying problems
Some basic house rules
Fill in ALL info asked for
Use units requested on results sheet
Report to correct decimal
as detailed in method
Null = test not undertaken therefore no result submitted
0 (zero) is seen as a result & analysed as such

30. 2017 & Future plans All reports to be uploaded onto NLA website.
No more ed reports
Will need to log onto website to access reports
Will trial the electronically submission on next asphalt round Nov’17
If results entered incorrectly, analysed as submitted
To assist in quicker turnaround times for
Benefit of labs needing to take action
For accreditation purposes
Looking at adding MatCivils PTS added to NLASA ISO accreditation schedule into 2018
Require some additional info before adding to schedule
Hoping to by then be using the SANRAL reference lab in Pretoria to prepare all samples.

31. Keep at it – we’re making progress !!
In closing… as always
Building towards a more professional laboratory environment that will be seen as being
Trustworthy
Honest
Quality driven
Thank folks…
Purpose
to improve consistency of results between labs
Assist in identifying your own internal areas that require attention
addressing these issues
Improving the consistency of the methods being used between laboratories
Besides being a requirement for SANAS accreditation
Keep at it – we’re making progress !!