MOISTURE IN PAVEMENTS
The pavement moisture regime reaches an equilibrium under the centre of a sealed road (or runway) over a deep water table. This can be predicted, and my first PhD was on that topic. It is often important to be able to judge how "wet" the layers of a pavement are, and these prediction methods can be used to do that. I have summarised the data and knowledge into one page on moisture .
SIMPLE PAVEMENT DESIGN CHART
I only use this as a very rudimentary rule-of-thumb check, and it is not substitute for proper pavement design. However, from AUSTROADS (2001), the pavement thickness design chart for thin bituminous surfacings is here WARNING - this does not analyse for specific basecourse or subbase performance and the road can also fail in those layers.
DCP ANALYSIS AND DESIGN CHART
Dynamic Cone Penetrometer. DCP.
Great engineer's tool. A J Scala (1962) got it up and running for subgrades in Australia. Then Burrows and Ed Kleyn (1983) extended its use to all pavement layers in the old Transvaal Provincial Administration. Dr Frank Netterberg turned it into a serious scientific and research tool. I was involved in redesigning it for improved reliability in 1983. An unnamed US Corps Engineer took the design drawings back to Vicksburg in 1984 (I gave my set to him personally). And now, in the 21st century, even America has discovered it (complete with the South African drawings) and are promoting it an excellent tool. They even left in the dumb bits of my redesign.
The DCP results can be used to divide a road or runway into uniform sections, get design subgrade strengths and thus feed into FAA design charts, or estimate elastic moduli and feed into the various (APSDS, LED) computer elastic layer design programmes for runway thickness. It feeds into the various road design catalogues (TRH 4, AustRoads). In the field, it can be an important tool to investigate failures and help find their cause. IT IS VIRTUALLY THE ONLY TOOL THAT FINDS THIN WEAK INTERLAYERS such as partially soaked layers or clay lenses - in basecourse, subbase, or subgrade (unless you count Prof Emile Horak's layer analysis of FWD results). It is also very useful for finding problems inside the basecourse, especially at the top where the base may be crushing or too weak to resist seal aggregate penetration and you have seal bleeding. The DCP can even be used to help understand FWD test results.
Above all, the DCP is marvellous for sorting out the confusion that arises when all the various test results are put together. Usually when a pavement has been evaluated, there is so much data that it doesn't make sense. One test shows a section is about to fail, while another test shows it is the strongest section. The DCP is the "honest" tool to help you sort out what is what. Warning - only one group have got a successful way of analysing the results in software - Fritz, Fenella and the team at Modsys (the Rubicon Toolbox software) since most other algorithms get confused by non-standard conditions (which of course is what you're using the DCP to look out for). If you haven't got Rubicon, an hour or two of pencil and ruler and charts plus sweat labour gets most projects analysed.
I've written up a guide for competent geotechs on how it can used - click here for that Word file, and here for the DCP chart to plot field results and get CBRs (and with the DCP-CBR correlation table). And here to see what a completed chart looks like. WARNING this chart is for the DCP model (fall, weight, cone) as noted on the chart - check yours is the same; and remember that field DCP and CBR are affected (sometimes greatly) by moisture; and that the heterogeneity of natural materials means that there is an imprecision about all this. (here is the DCP test method).
Some of the South African test methods are online (well done Barry).
The ones online are in bold - click for them here TMH methods on-line
TMH1: Standard methods of testing road construction materials 1986
TMH2: National standard for the spraying performance of binder distributors 1979
TMH3: Traffic axle load surveys for pavement design 1988
TMH5: Sampling methods for road construction materials 1981
TMH6: Special methods for testing roads (here is the DCP test method)
TMH7: Code of practice for the design of highway bridges and culverts in SA, 3 Parts 1989
TMH9: Pavement management systems: standard visual assessment manual for flexible pavements 1992
TMH10: Manual for the completion of as-build materials data sheets 1993
TMH12: Pavement Management Systems: Standard Visual Assessment Manual for Unsealed Roads 2000
Bitumen - Australian grade- temperatures
Key temperatures including softening point, rolling temperatures, mixing temperatures. For all Australian grades, multigrades, and PMBs. Click here for that extract from the very useful "AAPA Code of Practice: Manufacture, Storage and Handling of Polymer Modified Binders, 1st edition, June 2004. Melbourne, Victoria."
And when you wanted to know what was in each PMB grade: