This article presents the test results for the physical and mechanical properties and fracture toughness of polymer-modified hydraulically-bound mixtures (HBM) produced with Portland cement for road base layers. The modifier used was a redispersible polymer powder (RPP) based on a vinyl ethylene acetate (EVA) copolymer obtained by spray drying. A three-level full factorial design with two factors was applied to determine the contents of Portland cement and polymer powder in the cement-bound mixture (CBM). Both Portland cement and polymer powder were added at three levels: 0%, 2%, and 4%. The assessment included basic physical properties (water absorption, density, and bulk density) and mechanical properties (stiffness modulus, axial compressive strength, and indirect tensile strength) of the CBM. Particular attention was paid to the assessment of fracture toughness in the semi-circular bending test. The results of the research show that polymer powder positively influenced the mechanical properties of CBM by improving its cohesion while maintaining its stiffness. Another benefit coming from the use of polymer powder was the CBM’s increased resistance to cracking, which is the desired characteristic from the perspective of pavement durability.

This paper presents the effect of modifiers on the properties of a mixture of asphalt concrete with bitumen emulsion (ACBE). The mineral-asphalt mixture is the only one that can be produced using the cold-mix technology (CMA). The theoretical part of the article details the characteristics of the methods for producing mineral-asphalt mixtures in terms of their production temperature. Thus, hot (HMA), half-warm (H-WMA), warm (WMA) and cold (CMA) mixtures are discussed. The research section presents the design of the asphalt concrete composition with bitumen emulsion, the research methods, the experiment design and the research results. The design of the mixture of asphalt concrete with bitumen emulsion was carried out in accordance with the guidelines set out in EN 13108-31. In the experiment, Portland cement (C), bitumen emulsion (A), synthetic latex (styrene-butadiene rubber SBR) (B) and redispersible polymer powder EVA (polyethylene-co-vinyl acetate) (P) were used as modifiers. Twenty-four mixtures were designed as part of the experiment, according to the 3⁴ experiment design. The following physical and mechanical properties were assessed in the design of the research: air void content V_m, water ab-sorption n_w, indirect tensile strength ITS and IT-CY stiffness modulus. When analysing the research results, the authors observed a noticeable impact of the content of asphalt (A) and synthetic latex (B) on the air void content V_m. A significant effect was also observed for the interaction of Portland cement (C) and redispersible polymer powder (P) on the indirect tensile strength ITS. The next step was the optimisation of the ACBE mixture composition, which effect made it possible to identify the optimum amounts of modifiers in the mixture of asphalt concrete with bitumen emulsion (ACBE), which constituted recommendations for the requirements for mixtures of asphalt concrete with bitumen emulsion.

The article presents the impact of a polymer modifier (P) on the properties of mineral-cement-emulsion (MCE) mixes. The theoretical part of the article discusses the ways of producing mixes using deep cold recycling. The “in-place – on site” and “in-plant – delivered” production methods are described. The paper also presents a description of a redispersible polymer powder (RPP) used as the polymer modifier. The part dedicated to the conducted research presents the experiment design and discusses the research methodology used to evaluate the effect of the polymer modifier on the properties of the MCE mix. The project involved the production of MCE mixes varying in terms of the type and amount of polymer powder, cement and bitumen emulsion. Mixes were designed with a variable share of cement range from 0.5% to 3.5%, a share of bitumen emulsion ranging from 0% to 5% and a fraction of redispersible polymer powder from 0.5% to 3.5%. A total of 15 mixes were made as part of the experiment, designed according to the Box-Behnken experiment design. The following physical and mechanical properties were assessed in the plan of the research: air void content Vm, water absorption nw, indirect tensile strength ITS, water damage resistance TSR, IT-CY stiffness modulus and SCB fracture toughness. The test results were analysed to assess the impact of the redispersible polymer powder on the properties of the recycled MCE mix. Following the analyses, the composition of mix was optimised regarding the requirements set out in the Polish design guidelines.