Clegg Hammer

[Jenny]

Can someone please tell me what the Clegg Hammer reading on the synthetic is?Cambridge a 72. Awapuni a 60 and Ricc didn’t appear to have one. 

[Chief Stipe]

WTF is the Clegg Hammer reading?  Haven't seen it reported anywhere!

[Pete Lane]

Impact Soil Tester

[curious]

47 minutes ago, Chief Stipe said:

WTF is the Clegg Hammer reading?  Haven't seen it reported anywhere!

It's being reported but Riccarton seem to have lost theirs already.

[Shad]

51 minutes ago, Chief Stipe said:

WTF is the Clegg Hammer reading?  Haven't seen it reported anywhere!

Thought he was Jack's brother.

[curious]

WTR @ Cambridge Synthetic| Wednesday 21 May

Tuesday Afternoon

Weather: Fine

Track: Synthetic

Clegg Hammer: 72

Rail: True

Rain: No Rain Last 24 Hours | 3mm Rain Last 7 Days

Irrigation: N/A

Weather and Track updated at 3.42pm Tuesday 20 May

[Dark Beau]

2 hours ago, Jenny said:

Can someone please tell me what the Clegg Hammer reading on the synthetic is?Cambridge a 72. Awapuni a 60 and Ricc didn’t appear to have one. 

Curious, for Jenny and my education which is firmer…Cambridge at 72 or Awapuni at 60?

I once had a filly run at Cambridge when it was firm, (Clegg Hammer unheard of) and she ran a beaut 2nd. 

Three weeks later she went back there for the Maiden Finial and she very poorly BECAUSE the track was prepared very differently. They fluffed it up so much that it was the equivalent of a heavy track. 

At the time I didn’t even know that they could do that!

Anyway believe it or not, she is down to have her first run again on a synthetic surface at Awapuni on Sunday and I am quite confident except now Awapuni is vastly different to Cambridge, (according to the Cleg Hammer) so what is what?

Which one is firm, which one is fluffy, hence deep.

What do the figures pertaining to the Cleg Hammer mean. 

Can Chief (or Curious) please delve into this and advise us poor mortal souls?

 

 

 

 

[Special Agent]

Sounds like a case of blind them with science.  Maybe it's science fiction.

[curious]

Higher readings mean the track is more compacted, so faster. You'd expect to see quicker times at Cambridge than Awapuni. It's not a very tight correlation though.

Edited 11 hours ago by curious

[curious]

Temperature is a much better predictor of race times than either the Clegg or penetrometer for synthetic tracks.

[Bill]

7 hours ago, curious said:

Temperature is a much better predictor of race times than either the Clegg or penetrometer for synthetic tracks.

 

Used in HK on the dirt

https://racing.hkjc.com/racing/english/racing-info/racing_course.aspx

[Chief Stipe]

7 hours ago, curious said:

Temperature is a much better predictor of race times than either the Clegg or penetrometer for synthetic tracks.

 

That's nonsense piece of research.

Effect of temperature on race times on a synthetic surface

 

M. L. PETERSON, R. F. REISER II, P.-H. KUO, D. W. RADFORD, C. W. Mc ilwraith

[Chief Stipe]

16 hours ago, Pete Lane said:

Impact Soil Tester

Actually it is a soil compaction tester.  Not sure it has any value particularly if track has been prepared correctly on raceday morning.  I assume they do that.

Any correlation to temperature is probably related to the older style waxes used 15 years ago where they "melted" as temperatures rose during the day.  My understanding is that this "problem" has been addressed with better waxes and fibre/sand ratios.

Of course water was used on the older style tracks to adjust firmness and limit wax breakdown but I recall reading that these new AWT's are supposed to not need that.

[Freda]

9 minutes ago, Chief Stipe said:

That's nonsense piece of research.

Effect of temperature on race times on a synthetic surface

 

M. L. PETERSON, R. F. REISER II, P.-H. KUO, D. W. RADFORD, C. W. Mc ilwraith

How can you make that statement?     It does seem as if temperature has an effect on the wax part of the composite, therefore must have some bearing on speed/times.

Apart from the fact that it was first published in 2010 so may be rather out of date.

[Chief Stipe]

7 minutes ago, Freda said:

How can you make that statement?     It does seem as if temperature has an effect on the wax part of the composite, therefore must have some bearing on speed/times.

Apart from the fact that it was first published in 2010 so may be rather out of date.

The hypothesis may be true but the study in my opinion was flawed and doesn't prove a correlation between time and temperature.  It involved the comparison of races (in the afternoon) and fast work (in the morning) over a 42 day period.  So the lower temperature times were presumably "fast work" times.  It isn't clear in the study how they normalised the data or accounted for confounding factors.

Yes as I posted before I read your response temperature can affect the wax in the poly profile however significant advances have occurred in the last 15 years since the study.  Not that I've seen the formula but it is possible that the type of waxes and sand/artificial fibre ratios used vary between the 3 AWT's in NZ.

[curious]

44 minutes ago, Chief Stipe said:

That's nonsense piece of research.

Effect of temperature on race times on a synthetic surface

 

M. L. PETERSON, R. F. REISER II, P.-H. KUO, D. W. RADFORD, C. W. Mc ilwraith

Alison J. Northrop, Jaime H. Martin, Danielle Holt, Sarah J. Hobbs,
Operational temperatures of all-weather thoroughbred racetracks influence surface functional properties,
Biosystems Engineering,
Volume 193,
2020,
Pages 37-45,
ISSN 1537-5110,

 

[Chief Stipe]

17 minutes ago, curious said:

Alison J. Northrop, Jaime H. Martin, Danielle Holt, Sarah J. Hobbs,
 ,
Volume 193,
2020,
Pages 37-45,
ISSN 1537-5110,

 

This is a different Study to the one you first posted.

It compared 3 temperatures - you'd expect the frozen surface i.e. zero degrees to be harder than the 40 degree one.   Surface functional properties were quantified for samples of the UK all-weather racetrack surfaces (n = 6) under three controlled operational temperatures (0 °C, 20 °C and 40 °C)

Also the change in firmness occurred from compaction as 3 tests were done in the same spot.  That could be an argument for grooming more regularly.

Findings were individual to each track, indicating that properties specific to the surface material such as fibre type, sand morphology, age and wax composition all play a role in the surface's response.

My interpretation of the results is - the lower the temperature the firmer the track.  At higher temperatures the track is softer but more susceptible to compaction.

31948 ViewPageProof_YBENG_3047.pdf

[Pete Lane]

1 hour ago, Chief Stipe said:

Actually it is a soil compaction tester.  Not sure it has any value particularly if track has been prepared correctly on raceday morning.  I assume they do that.

Any correlation to temperature is probably related to the older style waxes used 15 years ago where they "melted" as temperatures rose during the day.  My understanding is that this "problem" has been addressed with better waxes and fibre/sand ratios.

Of course water was used on the older style tracks to adjust firmness and limit wax breakdown but I recall reading that these new AWT's are supposed to not need that.

From the Clegg Hammer website but obviously you know best.

The CLEGG HAMMER or Clegg Impact Soil Tester (CIST) is a falling weight deflectometer that measures the stiffness of soils or pavements to assist engineers to determine the ability of the pavement to support load.

[Chief Stipe]

16 minutes ago, Pete Lane said:

From the Clegg Hammer website but obviously you know best.

The CLEGG HAMMER or Clegg Impact Soil Tester (CIST) is a falling weight deflectometer that measures the stiffness of soils or pavements to assist engineers to determine the ability of the pavement to support load.

It was originally designed to provide an easy repeatable method of determining the CBR (California Bearing Ratio) value of road material which is a measure of its strength.  Strength being a description of compaction.

The first version of the Clegg Hammer was developed by Dr. Baden Clegg in Australia and was named ‘The Clegg Impact Soil Tester’ (Figure 3). It was first introduced at the 8th Australian Road Research Conference in 1976 [6]. Since then, it has been widely used in Australia and Europe. It is currently manufactured in the United States (Table 1) and is being used by consultants and contractors in several compaction control applications and particularly in the compaction testing of sports fields.

The Clegg Hammer is similar to many other soil compaction measuring devices in that it does not provide direct readout of soil density or soil moisture values like the NDG. It monitors soil strength-stiffness after the application of impact force on the soil. However, the output of the device provides a measure of soil densification and it can be successfully used when it is calibrated to compaction efforts and moisture conditions for various soil types.

It does NOT directly measure sheer which is important for horse racing.  

So in terms of the AWT's it measures the degree of compaction of the poly-fill.  If the track has been groomed correctly then this should be the same every meeting assuming that the moisture levels are the same.  In my opinion temperature during the 4 hours of a meeting wouldn't have much impact.

clegg-hammer.pdf