Page 105 - SAPEM-Chapter-10-2nd-edition-2014

South African Pavement Engineering Manual
Chapter 10: Pavement Design

Advantages of the PN Method Disadvantages of the PN Method
• Relatively easy to apply and robust • Limited to Category A and B roads
• For new and rehabilitation design • Limited to between 1 and 30 million E80s
• For initial and detailed assessments • Cannot be used where subgrade of CBR < 3%
• Evaluates the adequacy of individual layers in the within 600 mm pavement depth
pavement system • Currently should not be used for asphalt
• Calibrated for southern African conditions using surfacing thicker than 50 mm
performance data from existing pavements
• One of the few methods calibrated for BSM layers
• Easy to implement in a spreadsheet

7.3 Dynamic Cone Penetrometer (DCP) Method

The DCP design method is for new and rehabilitation pavement design. It is an empirical method that incorporates
concepts such as pavement balance (see Section 3.4). The Dynamic Cone Penetrometer (DCP), shown in Figure 41,
is a fairly basic evaluation instrument. However, the analysis and interpretation of DCP data have evolved to the
extent where it may be used as a design tool in South Africa (Kleyn, 1984; Kleyn et al, 1989; Sampson, 1984;
Jordaan, 1989a; and De Beer, 1991). The DCP device and measurements are described in Chapter 6: 7.4.5.

DCP References
A good reference for the DCP design
method is:
• P Paige-Green, P. and Du Plessis,
J.L. 2009. The Use and
Interpretation of the Dynamic
Cone Penetrometer (DCP) Test.
CSIR Built Environment. Pretoria.
• Paige-Green, P. and Pinard, M.I.
2012. Optimum Design of
Sustainable Sealed Low Volume
Roads using the Dynamic Cone
th
Penetrometer (DCP). 25 ARRB
Conference. Perth, Australia.
Figure 41. Dynamic Cone Penetrometer (DCP)

The DCP design method was developed and calibrated for new and rehabilitation design of granular and lightly
cemented pavements. This design method has been verified with a number of HVS tests and by use in the industry
for many years. The method is suitable to light pavement structures with mostly unbound granular or lightly
cemented layers.

The important concepts involved in the DCP design approach and the input parameters required are:
• DCP penetration rate, DN (mm/blow).

Section 7: Structural Capacity Estimation: Flexible Pavements
Page 94