STUDIES ON FOAMED ASPHALT MIXES CONTAINING RAP

Abstract

The environmental and safety aspect on road transportation systems as a whole is generally ignored as it has a small contribution, in comparison to construction and maintenance process. However the environmental and safety impact of construction and maintenance techniques should not be ignored. Cold Mix technology is viewed favorably in terms of both safeties of workers, emissions and energy consumption/ global warming potential. Cold manufactured bituminous road materials, whether prepared with foamed bitumen or emulsions have inherent advantages over hot mix. Energy consumption and global warming potential and resource depletion are lower: A cold mix constructed roadway requires use only 60-70% of the energy of a hot mix roadway in a similar situation. During paving of solvent-free emulsion cold mixes, exposure of workers to hydrocarbon fumes is eliminated. Field measurements have confirmed that lower paving temperatures of cold or warm mix lead to lower fume exposures. ABSTRACT Dense populated cities where environmental pollution is a serious threat are of prime concern for the Highway engineer. Conservation and optimum utilization of the road building materials specially petroleum and mineral aggregate is the second aspect which requires immediate attention. The rehabilitation and up gradation of existing badly distressed pavements due to rapidly growing heavy vehicular traffic are also attracting attention. An immediate action is required towards the development and implementation of Eco-friendly pavement construction technologies. Through application of these technologies the efficient use of existing and waste materials can be made without creating problems to the environment and at the same time meeting the quality requirements of the pavements. Advances in technology and techniques in the in recent years have made cold mix and half warm mix technologies an increasingly popular and cost-effective pavement construction and maintenance technique. It has been proved in abroad that cold mix technology can be an option which has the potential to address the above mentioned issues. Among many Cold Mix Technologies, Foam Bitumen and Bitumen (Asphalt) Emulsion is the leading one which proving it in every context in front of the Hot Mix Technology. Presently, Emulsion is mostly used for Prime Coat, Premix Carpeting and for the Repair Works. Very little work has been carried out for the mixes with fines in India. Cold technologies represent the future techniques in road surfacing. These cold mixes are energy efficient as well as iii environment friendly. The dissertation aim is to develop half warm mixes with different materials. The improved aggregate-binder systems resulting can be used in both base course and wearing course application. This works is an effort to encourage the cold in place recycling process and examines its benefits compared to other methods of rehabilitating and upgrading road pavements. Also covered are the engineering properties that can be expected when road building materials are treated with the various stabilizing agents. Recommendations are given for the choice of the most cost-effective stabilizing agent depending upon a number of variables. In this study, an effort is made to analyze the behaviour and performance of Foam bitumen as base course with Recycled material. Wearing Course or surface course was tried with fresh aggregate and Bitumen emulsion. Analysis of the behaviour of many Regular and Polymer Modified Cationic Asphalt Emulsion with various gradation of SDBC with and without cement is discussed. The laboratory investigation of the Marshall Stability, Flow Value, Bulk Density Percentage Voids and strength parameters like indirect tensile strength, resilient modulus, resilient modulus etc. were carried out. The impact of such practices on economic and environment perse has also been discussed in detail with life cycle assessment.