A literature review on moisture resistance performance of bitumen modifiers

Moisture damage in the bituminous layer is one of the major causes of deterioration in the functional and structural performance of the flexible pavements in the field. This will result in an increase in the maintenance and rehabilitation cost of the pavement and the vehicle operating costs. Hence, it is quintessential to reduce the intensity of moisture damage in the bituminous mixes to prevent the costly maintenance of flexible pavement and the increase in vehicle operating costs. The variation in moisture resistance of bitumen or bituminous mixes produced with different types of bitumen modifiers indicates that apart from the type of aggregate, the modifier used for modification of bitumen also influences the moisture resistance performance of bituminous mixes. However, the effectiveness of bitumen modifies to mitigate the moisture damage in the bituminous mix is also varying with the type of modifier, content of modifier, type of aggregate, moisture conditioning period, severity of aging, and pavement characteristics. Hence, understanding the factors alleviating the effectiveness of bitumen modifiers to control moisture damage in the bituminous mixes is essential. This will help in the selection of the proper type and content of bitumen modifiers for the construction of roads with the least chance of damage caused by moisture intrusion in the pavement. This review documented the impact of different bitumen modifiers on moisture damage. Finally, the recommendations for the future study are provided based on the gaps identified in the current literature.