-----Original Message-----
From: שמעון נסיכי [mailto:[log in to unmask]]
Sent: Thu 24/07/2003 15:06
To: [log in to unmask]
Cc:
Subject: SMA MIXTURES VS. "CONVENTIONAL" DENSE GRADED AND SUPERPAVE MIXTURES
REPLY>
I am personally involved in research (desk study) of the early life skidding resistance problems that may (or may not) exist on SMAs and other "thin-surfacings" that use a relatively high % of high specification binders with or without fibres or additives......
[log in to unmask] for direct contact please
Literature exists from Holland of the low dry skid resistance of Porous Asphalt on first opening AND one documented instance in the UK of a road with as low a dry skid resistance (Mu) as WET ( normally dry skid resistance is HIGH (0.7-0.9) compared to normal wet skid resistances on natural aggreates of 0.4-0.7 (approx))
Only one device is accessible to the UK highway engineer that can offer repeated and safe measures of dry grip...
the KJ Law PFT ( now the Dynatest 1295 Friction Trester).... The police use a skid car with SKIDMAN
The SMA type materials have advantages in terms of ease of construction ( lane closures), the negative textures reduce road noise and may enhance skid resistance ( reference the MARS project as yet UNPUBLISHED by TRL) ... longer term durability is 10-20 years? but difficult to tell with the older materials being so young!!!!
Quality ( excluding skid resistance which is assumed to be good as high PSV stones are used) , is specified in the UK for commercial materials via HAPAS ( http://www.bbacerts.co.uk)
Need more?
John C Bullas
Ex TRL, Summer secondment to
Dynatest UK thence to Tyre Safety PhD
University of Southampton
Dear Group Members,
Is anyone aware of research reports or studies comparing the performance, cost and probably life cycle cost analysis of the above mentioned mixtures?
Thanks
Shimon Nesichi, M.Sc.,
Managing Director,
Materials and Research Division,
Public Works Department,
Ben Zvi Rd. 55, POB 49057
Tel Aviv, 61940
Israel
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