Abstract: Objective: The effects of type and amount of portland cement as a traditional additive and carboxylated styrene-butadiene emulsion (Rovene® 4045) as a non-traditional additive on the short-term and long-term performance of road base layer were investigated using laboratory mechanistic evaluation of stabilized soil-aggregate mixtures. Methodology: Cylindrical specimens were stabilized with portland cement (0-6%), Rovene® 4045 (5-10%); then, the specimens were molded; cured for 7, 28 and 60 days and then subjected to different stress sequences to study their unconfined compressive strength, indirect tensile strength and indirect tensile resilient modulus. The long-term performance (durability) of stabilized soil-aggregate specimens was investigated by conducting wetting and drying (WD) cycling tests on 7 days cured specimens. Results: The WD cycling tests showed that the addition of a 4% portland cement 7% Rovene® 4045 mixture resulted in a 410.6% improvement in water absorption, a volume change of 498.18% and a weight change of 1012% as compared to the sample with 4% cement after 12 WD cycles. Conclusion: This study presents the finding of a correlation conducted to determine the influences of affective variables using non-linear regression analysis to establish significant models with the aim of predicting the strength based on mixture parameters.