The process of water-based foaming of bitumen produces binders that can be incorporated in cold recycled asphalt mixes and pavement upper structural layers made of half-warm mix asphalt prepared at 100–130 °C. During the foaming process, cold water and air act on hot bitumen (160–170 °C), which results in the explosive vaporization of water leading to changes in the binder structure. The impact of foaming on the properties of bitumen 70/100 was evaluated by investigating the binder characteristics before and after foaming. Determination of two foaming parameters, maximum expansion and half-life, was followed by measurements of penetration at 25 °C, softening point, Fraass breaking point, and dynamic viscosity at 60, 90, and 135 °C. Rheological and low-temperature tests were also performed before and after foaming bitumen 70/100. The Bending Beam Rheometer method was applied to determine the low temperature stiffness modulus. A DHR-2 rheometer was used to determine the dynamic modulus and phase angle of the tested binder. The Black and master curves before and after foaming were plotted in the 2S2P1D model and the model parameters were analysed. Analysis of the test results confirmed the effects of the foaming process on the basic, low-temperature, and rheological characteristics of the bitumen.

The goal of this study is to evaluate how the inclusion of synthetic wax, added in 0.5% increments from 1.5% to 3.5%, affects the characteristics of PMB 45/80-65 (polymer-modified bitumen) during both short-term (RTFOT) and long-term (PAV) aging processes. Tests were carried out to assess the fundamental properties of the binder, leading to the determination of the penetration index (PI) and the plasticity range (PR). The binder’s properties were examined at below-freezing operating temperatures, with creep stiffness measured using a bent beam rheometer (BBR) at −10 °C, −16° C, −22 °C, and −28 °C. The rheological properties of the asphaltenes were evaluated based on both linear and nonlinear viscoelasticity. The experimental study explored temperature effects on the rheological properties of composite materials using a DSR dynamic shear rheometer at 40 °C, 60 °C, and 80 °C over a frequency range of 0.005 to 10 Hz. The main parameters of interest were composite viscosity (η*) and zero shear viscosity (η₀). Viscoelastic parameters, including the dynamic modulus (G*) and phase shift angle (δ), were determined, and Black’s curves were used to illustrate the relationship between these parameters, where G*/sinδ was determined. The MSCR test was employed to investigate the impact of bitumen on the asphalt mixture’s resistance to permanent deformation and to assess the degree and efficacy of asphalt modification. The test measured two parameters, irreversible creep compliance (J_nr) and recovery (R), under stress levels of 0.1 kPa (LVE) and 3.2 kPa (N-LVE). The Christensen–Anderson–Marasteanu model was used to describe the bitumen behavior during binder aging, as reflected in the rheological study results. Ultimately, this study revealed that synthetic wax influences the rheological properties of PMB 45/80-65 polymer bitumen. Specifically, it mitigated the stiffness reduction in modified bitumen caused by polymer degradation during aging at an amount less than 2.5% of synthetic wax.

The paper presents the influence of the ageing on viscoelastic properties of the bitumen at road pavement operating temperatures. The ageing process of bituminous binders causes changes in physical and mechanical properties of the bitumen. This phenomenon takes place in all stages of bituminous mixtures manufacturing, namely: mixing, storage, transport, placing. Nevertheless, during the service life it occurs the increase in stiffness of asphalt binder that is caused by the physical hardening of bitumen as well as the influence of oxidation. Therefore, it is important to identify the binder properties at a high and low operating temperatures of asphalt pavement after simulation of an ageing process. In the experiment as a reference bitumen, the polymer modified bitumen PMB 45/80-65 was used. The liquid surface active agent FA (fatty amine) was used as a bitumen viscosity-reducing modifier. It was added in the amount of 0,2%, 0,4% and 0,6% by the bitumen mass. All binder properties have been determined before ageing (NEAT) and after long-term ageing simulated by the Pressure Ageing Vessel method (PAV). To determine the binder properties at high temperatures the dynamic viscosity at 60°C was tested. On the basis of test results coming from the dynamic viscosity test it was calculated the binder hardening index. The properties at a low temperature were determined by measuring the creep modulus using Bending Beam Rheometer (BBR) at four temperatures: -10°C, -16°C, -22°C and -28°C. The stiffness creep modulus "S" and parameter "m" were determined. On the basis of dynamic viscosity test it was found that the ageing process caused a slight decrease in a dynamic viscosity. The level of a hardening index considerably increased at 0.6% fatty amine content. The long-term ageing process had a minor effect on stiffening of a polymer modified bitumen with FA additive regardless of a low temperature and an amount of fatty amine content.

Climate change necessitates the implementation of new technologies across all areas of human activity. These technologies should be energy - efficient and result in reduced greenhouse gas emissions. In road construction, the most energy - intensive process is the production of asphalt mixtures intended for the upper layers of road pavement structures. These are produced at temperatures ranging from 165°C to 180°C, depending on the type of asphalt used in the asphalt mixture. The production process is accompanied by the release of large quantities of greenhouse gases, including CO2. In addition to the negative environmental impact of producing asphalt mixtures, the high temperature also accelerates the ageing of the asphalt. As a result of oxidation processes, the asphalt’s viscoelastic properties deteriorate, causing it to stiffen and become brittle. The ageing process of the asphalt continues during the service life of the asphalt pavement. Mineral - asphalt mix is exposed to solar radiation, wind and water. As a result of the ageing process, the asphalt pavement may be subject to premature wear. In order to meet modern environmental and technological requirements, Warm Mix Asphalt (WMA) and Half Warm Mix Asphalt (HWMA) have been introduced into road construction practice. These are characterized by a lower temperature during production and incorporation into the pavement structure. They are produced at a lower temperature, typically between 35°C and 40°C, compared to traditional asphalt mixtures. Lowering the production temperature reduces greenhouse gas emissions and decreases the energy consumption of the production process. WMA and HWAM mixtures are produced using various suitable natural or chemical additives. The study utilized PMB 45/80 - 6 polymer - modified asphalt, to which WMA additives were applied in the form of synthetic wax at levels of 1.5%, 2.5% and 3.5% relative to the bitumen content, and a surfactant at levels of 0.2%, 0.4% and 0.6% by weight of the asphalt. The resulting binders were subjected to a long - term PAV (Pressure Aging Vessel) ageing process. The effect of WMA additives and the ageing process on the rheological properties of the binder was observed based on an analysis of changes in CMA (Christensen, Anderson and Marasteanu) model parameters, i.e. the cross - point frequency (fc), the rheological index (R) and the relative root mean square error (RRMSE). Based on the conducted research, conclusions were drawn regarding the significance of the influence of WMA additives in terms of long - term ageing on the rheological characteristics of PMB 45/80 - 6 polymer - modified asphalt, and recommendations were formulated regarding the quantities of additives to be used in the binder.

Foamed asphalt mixtures (FAMs) are considered to be among the most environmentally friendly. They are produced at temperatures ranging from 100 °C to 120 °C. In order to produce asphalt mixtures at such a low temperature, it is necessary to produce foamed asphalt binder with high foaming parameters, i.e., maximum expansion (ER) and a half-life (HLa) of the asphalt foam. Consequently, the asphalt binders were modified with a surfactant at a concentration of 0.6% by weight of the binder, prior to its foaming with water. Subsequently, an AC 8 S asphalt mixture was designed using traditional hot-mix asphalt (HMA) technology and with modified foamed asphalt binders in quantities ranging from 5.6% to 6.5% by weight, in increments of 0.3%. To ensure optimal properties of the FAM, hydrated lime was added at levels of 0%, 15%, 30% and 45% by weight as a substitute for filler. The influence of modified foamed asphalt binders and hydrated lime on the void content (Va), resistance to moisture and frost (TSR) and resistance to permanent deformation (WTS_AIR and PRD_AIR) of the FAM was assessed. A key element of the research was the determination of the complex modulus of stiffness E* and resistance to low-temperature cracking R₋₂, σ_cry, T_failure and crack propagation using the SCB methodology. Analysis of the test results using desirability functions enabled the determination of the optimum proportions of foamed asphalt binders and hydrated lime—5.9% and 30% respectively—in the FAM, ensuring that its properties meet all the requirements of the relevant standards and guaranteeing resistance to low-temperature cracking.