Investigation of Cold Recycling of Bituminous Surface Treatment with Foam Bitumen

Abstract

The course of turned of bituminous pavement layers into hot mix asphalt (HMA) layers has been increasing day by day all over the world. Bituminous surface treatment that contains consirable amount of aggregate and bitumen, is an important source of recycling that offers a great amount of pavement materials intead of virgin material usage on pavement consruction. In the study, it was aimed to investigate the usability of bituminous surface layer treatment in the base layers of the HMA roads by mixing with foam bitumen and active filler materials in order to eliminate the potential performance degradation that will be encountered when it is recycled due to the low bitumen percentage compared to hot mix asphalt and the wear of the aggregate due to climatic conditions and traffic loads over time. The study conducted that intends to technically evaluate the cold recycling of bituminous surface treatment of roads with foam bitumen and active filler materials; for 70/100 bitumen grade, 5 different bitumen mixes were prepared and ideal bitumen percentage was investigated for this bitumen grade. The effect of bitumen percentage on mixture performance was evaluated with 50/70-100/150-160/220 bitumen grades and mixtures were prepared in single bitumen ratio (2.5%). It was investigated that active fillers will give suitable results for foam bituminous mixtures by preparing mixtures for three different active fillers; cement, hydrated lime and fly ash. To evaluate all these productions, ITS, unconfined compressive strenght, triaxial resilient modulus and asphalt permanent deformation tests were performed. The results obtained showed that production made using 2% foam bitumen and 1% was found suitable for moisture sensitivity and structural stability. Recycling of bituminous surface treatment using foam bitumen and cement is an environmentally and economically beneficial method by reducing both waste and raw material consumption.