TECHNO-ECONOMIC ANALYSIS FOR CHOICE OF CEMENT CONCRETE PAVEMENTS

摘要

Concrete roads have very long and trouble free life, if they are well designed and properly constructed. There is almost no maintenance except for making and filling of joints. In making concrete roads local resources i.e. cement and aggregate are used. The Satara-Pune highway is being proposed now to be taken up as concrete road, and with a specialty of using high volume flyash concrete, not only to reduce the cost but also making concrete as durable as possible. For such new techniques, there is a need to make available to the practising engineers specifications on the construction of cement concrete roads using highly mechanised methods of batching, placing, transport, laying, finishing, etc. A good number of slipform pavers and ready mixed cement concrete plants are now available and also are being used at sites. Performance of such concrete roads which have been constructed and those being constructed should be evaluated so that the techniques can be improved and perfected to provide better concrete roads. There is need for in-depth study on durable joint sealing compounds, efficacy of liquid membrane curing compounds, plasticizers and admixtures compatibility, air entraining agents etc. The design of concrete roads, besides being based on the standard axle loading, should have the stress ratio concept built into it. Although the initial capital cost for concrete pavement is more than that of bituminous roads, the economics tilt in favour of concrete roads, when life cycle costing is adopted as it is significantly cost effective when considered in terms of total transportation cost. Concrete roads also provide lot of indirect savings to road users, such as fuel savings and reduction in travel time due to smoother surface and consequent higher speed. In case of heavy duty pavements, considering heavier and more traffic loading, more attention is required to be paid to surface characteristics, and economic factors in consideration of total transportation cost, particularly from the importance of having safe pavements and minimum interruption to traffic flow. There is little doubt that pavements of all types will meet this challenge in short term, but the individual choice for each new construction will be influenced to a large extent by the economic factors prevailing at the time of implementation of the project and the approach adopted by the agency towards life cycle cost and total transportation cost of the facility in long term.