Studies on mitigation of moisture damage in bituminous pavements

The process of stripping failure of aggregate-bitumen system in presence of water is accelerated by ions of salts and is thus responsible for early failure of open graded bituminous courses in salt infected areas. A quantitative assessment of stripping is not possible by available methods. The aim of this paper is to demonstrate mitigation of moisture damage in bituminous pavements using long chain fatty acid amine based additives. Results of studies reported in this paper indicate that measurement of indirect tensile strength under specified conditions of moisture soaking and immersion correlate well with stripping area of aggregates to the extent of 90-100%. Incorporation of 0.5% dehydrogenated tallow di methyl amine in bitumen prevents stripping of aggregates in presence of detrimental salt ions. Hence, failure of bituminous courses in salt infected areas can be prevented using these additives and life of surfacing can be extended. Indirect tensile strength ratio of Marshall specimen of open graded mix can be considered for quantitative assessment of stripping phenomenon.