A collaborative project, commissioned by AfCAP, between the Council for Scientific and Industrial Research (CSIR), South Africa, and experienced Low Volume Road (LVR) practitioners has made it possible the upgrade of the original Win DCP Software into a more user-friendly software tool designed to upgrading Low-Volume roads to paved standards using the Dynamic Cone Penetrometer (DCP). The software incorporates automated procedures for analysing DCP field data from the existing pavements as well as for laboratory testing and evaluation of imported materials as inputs for the design of new pavement layers. Thanks to the automation of several design procedures implemented in the DCP Software, the designer is able to quickly and easily evaluate different design options. However, it is important to stress that the ReCAP LVR DCP Software is only a tool and is no substitute for sound engineering judgment, which must always be exercised by the designer.
Since the early 1970s, in Africa and other regions of the world, a new testing device called the Dynamic Cone Penetrometer (DCP) has been introduced for the in-situ estimation of subgrade strength. The Dynamic Cone Penetration Test is performed by driving a metal cone into the ground by repeatedly striking it with a weight dropped from a standardised distance. The DCP offers two main advantages; its cost is relatively low compared to other equipment used for the same analysis and it also allows the subgrade strength to be calculated quickly in-situ in about 5-10 minutes. This makes the DCP ideally suited for designing the upgrading of existing roads to paved standards in low-income countries. However, another penetration test, the California Bearing Ratio (CBR), is the most widely used to design flexible pavement and the traditional calculations are based on the CBR test results. This method is more demanding, time-consuming and expensive than the DCP and requires the use of a specific laboratory apparatus to be performed. For this reason, the DCP has been developed through research into a full-fledged method for the structural design of low-volume paved roads that avoids the use of direct correlation with the California Bearing Ratio (CBR) test and instead use the DCP test results (DN value) as its input. Moreover, the DCP-DN pavement design procedure was developped and trialled successfully in several African countries. Long Term Pavement Performance (LTPP) monitoring of these sections has been carried out to collect additional in-service performance data to feed into the future revision of standards and specifications contained in current catalogues.
The DCP software has been improved to follow the constant and more recent developments and enhancements to the DCP-CN design method in 2018 and 2019. The ReCAP LVR DCP software also incorporates a User Manual containing the latest developments in DCP-DN design technology. The software and its helpline are freely available for practitioners and are hosted by the Council for Scientific and Industrial Research (CSIR), South Africa. On the ReCAP website in the Low Volume Roads DCP Software section, you can find the instructions on how to download the software as well as a number of useful and recent articles explaining more in-depth the characteristics of the DCP-CN design method.