AbstractSpent fluid catalytic cracking (SFCC) is an industrial waste from oil refineries that is increasing nonstop in Vietnam and many places globally, and needs to be recycled. However, SFCC has various compositions depending on the fluid catalytic cracking (FCC) types and additives in the petroleum-refining industry. Thus, an experimental optimization procedure is needed to find the optimum addition of SFCC as a filler powder for asphalt–concrete mixtures. For this requirement, the study objective was an optimization procedure based on Taguchi parameter design employing an MMDC parameter. MMDC, developed using a robust multivariate statistical method called principal component analysis (PCA), is a representative parameter of required performance quality proposed by the Marshall mixture design. The Marshall mixture design was used to verify the asphalt–concrete mixture in which SFCC filler partly replaced traditional limestone (LS) filler. The effect of LS filler rate on mixture characteristics was used to determine the required range of values of MMDC. Also, Marshall characteristics based on various SFCC filler rates verified the optimum methodology result. The confirmation experiment results showed that the approach could find an optimum case with advantages in reducing asphalt binder content in the mixture and the number of specimens in the laboratory. Furthermore, the experimental results indicated that SFCC filler could enhance the Marshall characteristics of an asphalt–concrete mixture.