Multicriteria-based optimization of roller compacted concrete pavement containing crumb rubber and nano-silica

Roller-compacted concrete pavement (RCCP) is a brittle material with low tensile strength that does not contain steel or dowel bars. This, in addition to the rigidity of the RCCP, causes degradation or cracking before the RCCP reaches its service life. To improve the performance of the RCCP, crumb rubber (CR) can be used as an aggregate. Hence, in this study, CR was used to replace 0, 10, 20, and 30% of the fine aggregate in the RCCP. To mitigate the adverse effect of the CR on the properties of the RCCP, nano-silica (NS) was added by weight of cement in proportions of 0, 1, 2, and 3%. To select an optimal mix based on various performance criteria, multicriteria-based optimization was carried out using techniques such as order of preference by similarity to ideal solution, evaluation based on distance from average solution, weighted sum model, and weighted product model techniques. During experimentation, CR improved the consistency and reduced the mechanical and durability properties of the RCCP, while NS reduced the consistency and improved the mechanical and durability performance of the RCCP. The M2 mix (mix containing 0% CR and 1% NS) is consistently ranked as the best choice for multi-criteria decision-making techniques and sensitivity analyses due to its exceptional physical, mechanical, and durability attributes, ensuring reliability across various decision-making scenarios. This study provides insights into the decision-making process for the choice of appropriate RCCP mix produced with CR and NS for improved performance in pavement applications and the importance of utilizing waste tire rubber in concrete pavements to promote sustainability.