The use of the semi-circular bending method to assess the intermediate-temperature fracture toughness of asphalt concrete mixes with reclaimed asphalt shingles

The article presents the results of crack-resistance tests of asphalt concrete mixtures with the addition of reclaimed asphalt shingles (RAS) performed using the semi-circular bending method (SCB). The aim of the work is to assess two aging conditions of the asphalt mixtures (short-term and long-term) on their fracture toughness. The flexibility index (FI), toughness index (TI) and, to a slightly lesser extent, cracking resistance index (CRI), turned out to be the most sensitive to the fracture toughness of asphalt mixtures subjected to various aging conditions. In the case of mixtures with the addition of RAS, it was observed that by changing the order of dosing the ingredients (adding RAS after new bitumen has been mixed with the aggregate), it was possible to reduce the negative impact of long-term aging on the resistance to cracking.