The normative technical documents applied in Lithuania establish the categories of properties of aggregates and aggregate mixtures to apply the mate-rials in the pavement structure base layers. In Lithuania, road pavement structures, in many cases, are designed using standardized pavement structure methodologies, which are based on historical empirical observations and experience. From 2019, with the addition of the M-E pavement construction method for roads of national importance, there is a need to determine the resilient modulus of unbound base layers’ materials, which is the main computational characteristic. The mechanical resilient properties of aggregates change depending on their geometrical and physical properties, the nature of the loads, and the functioning of the entire pavement structure. The dissertation analyzes the effect of the shape and resistance to fragmentation properties of aggregate mixtures used in the base layers of the pavement structure on the resilient modulus and the formation of permanent deformations under different external loads. The research methodology of aggregate mixtures has been applied, and tests have been performed in the laboratory for unbound mixtures of natural aggregates extracted from quarries and placed on the Lithuanian market. Two test methods were used to determine the resilient modulus: the triaxial periodic crushing test with constant lateral and low axial compressions — SS LSL MRT, and the multistage repeated loading test MS RLT. The MS RLT method was used to determine the permanent deformations. The dissertation results include the development of an algorithm for estimating the effect of the properties of aggregate mixtures on the resilient modulus and the formation of permanent deflections. The dissertation consists of an introduction, three chapters, a summary of the results, lists of used literature, and the author’s publications on the dissertation’s topic. The first chapter describes the construction methods and data requirements of the unbound base layer used in Lithuania and ab-road. Methods for determining the resilient modulus of aggregate mixtures are analyzed. The second section presents an experimental study of aggregate mixtures and their components and an analysis of the results. The third chapter evaluates the influence of aggregate mixtures’ properties on the resilient modulus and the formation of residual deformations. The k–θ and Erlingsson–Rahman models were applied to calculate aggregate mixtures’ resilient modulus and permanent deformations. The tested filler mixtures’ properties were ranked from the strongest to the weakest according to the correlation with the resilient modulus and permanent deformations.