The effect of using flux oil and RAP on the performance of pavement cold mix patching materials

Cold mix patching materials (CMPMs) are commonly used as an alternative to hot mix asphalt to repair potholes and localized distress in pavements. They are affordable, have a short application time, and have lower environmental impacts. Despite the advantages of CMPMs in treatment operations, they have relatively poor stability and workability, especially in cold weather conditions. This reduced performance can be managed by optimizing the mix design. In recent years, the use of flux oils has become common practice to reduce the binder viscosity and to provide the desired mixture workability and compactability. However, improving workability by decreasing the viscosity may lead to low stability. In this research, CMPMs produced by mixing a defined solid mineral skeleton (aggregate type and grading curve) and binder with variable amounts of flux oil and reclaimed asphalt pavement (RAP) were studied and analyzed. Specifically, the stability and workability of the products were investigated through the Marshall stability test and the indirect tensile strength test. The results showed that mixtures containing higher amounts of RAP were better compacted and less porous. Plus, the effect of flux oil on Marshall quantities (Marshall stability and quotient) and the strength of CMPMs was notable when the RAP used in the mixture was high.