Evaluation of cracking resistance of warm mix asphalt incorporating high reclaimed asphalt pavement content

Incorporating high Reclaimed Asphalt Pavement (RAP) content in manufacturing Warm Mix Asphalt (WMA) is more commonly used thanks to its economic efficiency and environmental effectiveness. However, when high RAP content is incorporated, the mixture's cracking tolerance needs to be controlled to achieve the durability of asphalt pavement. The present experimental work investigates the cracking tolerance of asphalt mixtures through a Flexibility Index (FI) and a Cracking Tolerance Index (CTIndex). For this purpose, warm-mix asphalt mixtures using Sasobit and Zycotherm additives are produced with RAP content at 30%, 40%, and 50%, respectively. The obtained results are also compared with Hot Mix Asphalt (HMA) with RAP content at 0% and 30%. The results show that, compared with HMA using 30% RAP, WMA using Sasobit has lower FI (12.1%), and WMA using Zycotherm exhibits higher FI (58.64%). Similarly, WMA using Sasobit has a lower CTIndex (12.8%), and using Zycotherm has a higher CTIndex (105.6%), compared with HMA using the same RAP content. Moreover, the results also show that the FI and CTIndex of WMA using Zycotherm are higher than Sasobit with similar RAP content. These values decrease with increasing RAP content. Lastly, the RAP content that ensures cracking tolerance could reach 40% in WMA mixtures using Zycotherm.