Managing SADC Roads Agencies in the New Millennium: The Role of Road Asset Management Systems
The management of the Southern African Development Community’s (SADC) road network is a complex task which is often influenced by a variety of factors – technical, financial, social and political – which all enter into the decision making process at various levels of their roads agencies. In such an environment, the determination of optimal strategies requires the use of a rational “systems” approach to road asset management. This paper outlines the road management strategy that is being pursued in a number of countries in the SADC region. It then illustrates how these systems are being used at various levels of application to achieve the desired objectives of the road agency.
LONG-TERM NETWORK PERFORMANCE - A FUNCTION OF MAINTENANCE STRATEGY
Most road agencies operate under a scenario where the maintenance need exceeds the available maintenance funds. In this environment pavement managers are forced to select maintenance and rehabilitation actions based on a defined methodology. Traditionally this was done through a ranking process where the maintenance priority was determined based on a road's importance and condition. Projects with a high priority rating were carried out first until the available funds were depleted. The more sophisticated pavement management systems utilise optimisation routines which allow for inter-project trade-offs when generating a maintenance plan. When utilising optimisation to select maintenance actions, various optimisation functions can be used. This paper shows how important the choice of maintenance selection methodology is on the long-term condition. Data from an actual road network is used and subjected to various ranking and optimisation functions. The outcome was evaluated in terms of long-term influence on network condition, overall transportation costs and asset value. It is shown that the analysis methodology selected should be compatible with the agencies' long-term maintenance objectives. (a) For the covering entry of this conference, please see IRRD abstract no. 878228.
The distribution of 54-Mn in the enamel and dentine of the rat incisor.
Abstract The distribution of 54 Mn was studied in the lower incisors of rats. Autoradiograms show 54 Mn to be present in the enamel and dentine 5, 10 and 15 days after its administration. In the dentine, the radioisotope is first localized in a zone near to and encircling the pulp and later becomes more diffuse. Pre-existing as well as the newly formed enamel incorporates the isotope. In both enamel and dentine 54 Mn appears to be principally associated with the inorganic portion.