The water resistance of a recycled base with foamed bitumen in the aspect of road binder composition

The paper describes research results of recycled base which was performedin a cold deep recycling technology with foamed bitumen and different type of hydraulicmixed binder in the aspect of water resistance. An individual design of a composition of abinder enables to achieve a precise adjustment of a binder’s impact to local conditions andrequired parameters of a recycled base. The design a recycled base with foamed bitumensimulated a cold deep recycling process with materials from existing crushed bituminouspavement layers ("technology in-situ"). To produce the foamed bitumen a road bitumen ofpenetration grade 50/70 was used. Moreover, the following mineral components werecategorised as a waste material: reclaimed asphalt pavement, 0/31,5 mm aggregate andaggregates for soil gradation improvement 0/4. A composition of the recycled base consisted of the binders prepared in the laboratory as a result of a mix of three basic components.The percentage of individual road binders was determined in line with the plan of thesimlex-centroid experiment. For the purpose of determining an influence of such a hydraulicroad binder on the water resistance in recycled base, the following tests were carried out:void contents Vm, tensile strength ratio TSR (water resistance). Additionally, an evaluationof increase of indirect tensile modulus (IT-CY) was conducted. On the basis of the testresults, a varied impacts of tested hydraulic road binders on mechanical properties andwater resistence of recycled base with foamed bitumen were observed. On the basis of theplan of the experiment, it was possible to determine the recommended road binder composition that enabled to obtain the water resistance in the recycled base with foamed bitumen