Investigating the effects of ageing on the properties of recycled asphalt concrete containing waste engine oil as rejuvenator

In this study the effects of short and long term ageing on some of engineering properties of recycled asphalt concrete containing high percentage of reclaimed asphalt pavement (RAP) and rejuvenated by different dosages of waste engine oil (WEO) have been investigated. The coarse fraction of asphalt concrete has been replaced with RAP and the mixture has been rejuvenated by different dosages, namely 0, 4, 7 and 10% (by the weight of total binder) of WEO, and the volumetric and Marshall properties, indirect tensile strength (ITS) and creep properties of the mixtures after experiencing different ageing conditions including un-aged, short term and long term ageing have been evaluated. Results reveal that inclusion of RAP into mixture increases the optimum binder content, Marshall stability and quotient, ITS and creep resistance; the Marshall stability and quotient, optimum binder content, ITS and creep resistance decreases with increasing WEO content. In un-aged condition, Marshall stability and quotient increase up to 7% of WEO content, beyond which the trend reverses. Also, ageing results in increase of Marshall stability, ITS and creep resistance, and decrease of flow with more effect after long term ageing. The degree of ageing effect on the properties depends on the type of ageing, type of mixture and amount of rejuvenator. The effect of ageing on Marshall quotient increases up to 7% of WEO content, beyond which decreases. For ITS the effect of ageing decreases with increase of WEO content, and for creep resistance, the effect of ageing increases with increase of WEO content. The Marshall stability and ITS are more affected by ageing in recycled mixtures than in control mixture and the level effect decreases with increase of WEO. Furthermore, results reveal that creep resistance is more affected from ageing than the ITS and Marshall properties. .