International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 7, Issue 1, pp: (46-51), Month: April 2019 - September 2019, Available at: www.researchpublish.com
WARM MIX ASPHALT Pramukh N1, Hemanth H2, Pooja R3, Rakshith H4, Charan kumar K M5 1
Pramukh N, Assistant Professor, Department of civil engineering JSS Academy of Technical Education Bangalore, 2345 Under Graduate students, Department of civil engineering, JSS Academy of Technical Education Bangalore.
Abstract: Warm mix asphalt (WMA) is a relatively new technology. It was developed in response to needs for reduced energy consumption and stack emissions during the production of asphalt concrete, improved workability and compaction after long hauls and when using lower placement temperatures, and better working conditions for plant and paving crews. Studies in the United States and Europe indicate that significant reductions in production and placement temperatures, and, potentially, in related emissions are possible. However, concerns exist about how these lower production and placement temperatures could influence asphalt binder aging and, consequently, short- and long term performance, specifically rutting. The testing completed in this warm mix asphalt study provided no results to suggest that warm mix technologies should not be used in conventional, gap-graded asphalt rubber, and open-graded friction course mixes in California, provided that standard specified mix design, construction, and performance limits for hot mix asphalt are met. The use of warm mix asphalt has clear benefits when compared to hot mixes. These include significant reductions in, or even elimination of, smoke and odours, lower emissions, improved workability, better working conditions, and better performance on projects with long hauls or where mixes are placed under cool conditions. The slightly higher costs of using warm mix technologies are outweighed by these benefits. Based on the findings of this study, the use of warm mix Keywords: Organic additive: SASOBIT (Paraffin wax), Chemical additive: EVOTHERM (Soya wax).
1. INTRODUCTION Over the last two decades, the production and appliance of asphalt mixtures have been improving, particularly to achieve economic and environmental objectives. Recently, the improvement has paid more attention to the reduction of energy consumption throughout the process, without changing the in-service mechanical performance of these asphalt mixtures. There is a growing international pressure on the reduction of fossil fuels consumption and the emission of greenhouse effect gases (GHG) such as carbon dioxide If a significant temperature decrease could be achieved within the production practice of asphalt mixtures, while the workability of the material is adequate and mechanical performance attained is the same as or even better than HMA, the gain for the environment and the society in general would be significant. The hot-mix asphalt industry is constantly exploring technological improvements that will enhance the material’s performance, increase construction efficiency, conserve resources, and advance environmental stewardship. It is logical that one approach to achieving these goals would involve methods to reduce material production temperatures. The concept of warm-mix asphalt has been introduced over the last few years as a means to these ends. Warm-mix asphalt is produced at temperatures in the range of to lower than typical hot-mix asphalt (HMA). The production and placement of HMA pavements has evolved over the last 130 years from hand mixing and manual placement with rakes and shovels to computerized plants feeding highly automated remixing, placement, and compaction equipment that track location and material quality. During this period, it has become recognized that temperature control is crucial to aggregate coating, matrix stability during production and transport, ease of placement, compaction, and ultimately the performance of the pavement.
II. ADDITIVES USED IN WARM MIX ASPHALT MIXTURES ORGANIC ADDITIVE: Sasobit is a product of Sasol Wax (formerly Schümann Sasol), South Africa. Sasobit is described as a modifier or "asphalt flow improver". It is available in 2, 5, 20 and 600 kg bags. On request it can be supplied in flakes or powdered form. Sasobit is a fine crystalline, long chain aliphatic hydrocarbon produced from coal gasification using the Fischer-Tropsch (FT) process and is otherwise known as an FT paraffin wax.
Page | 46 Research Publish Journals