This article discusses the results of bitumen foam properties optimisation with respect to three factors: air pressure, bitumen temperature and amount of water. The test materials were unmodified bitumen 50/70 and bitumen 50/70 modified with 2.5% synthetic wax. The experiment was designed according to the 3⁽³⁻¹⁾ fractional factorial design. The distribution of parameters of bitumen foam were measured with the authors’ original apparatus using a laser beam. This measurement method increased the accuracy of maximum expansion ratio (ER) and half-life (HL) estimation. Based on HL and ER results, it was found that the foaming process increased bitumen stiffness due to the dynamic ageing of the bitumen. The experimental design allows more effective control over the properties of foamed bitumen with respect to its intended use. The presence of synthetic wax extended the half-life of the bitumen foam.

In 1999, during rebuilding and modernization of the one of the main streets in Kielce (Poland) it has been placed SMA wearing coarse layer with the hydrated lime. SMA mixture contained 6.2% of D70 bitumen (currently 50/70) and 4% SBS polymer labeled as Kraton 1101 CM. Hydrated lime was dosed into SMA mixture to replace 30% of filler mass. Pavement surface condition after 12 years of service life was very good. In 2011 bitumen, extracted from SMA, tests were made. The tests covered bitumen samples which contained the fatty amine and the hydrated lime as a adhesive agent. Bitumen samples were obtained from SMA wearing course layer at the site of the rut and out of the rut. On the basis of the rheological properties the recovered binder with hydrated lime had a positive effect on reducing aging process of bitumen 50/70 modified with SBS polymer in SMA mixture giving the increase in resistance to the water and frost effect

The research focused on the application of mixed binder system to the hydraulically bound mixes used in road base (HBM). This paper presents the outcome of the tests for the mechanical characteristics of the HBM road base in terms of the binder type used. Seven binders were prepared in a laboratory by blending three primary constituents: Portland cement CEM I 32,5R, fluidised bed combustion fly ash and cement kiln dust (CKD). The proportions were selected according to the experimental design. The percent amount of the binder in the hydraulically bound mixture was 6%. Two types of aggregate were used as the mineral material in the base. The composition of the mixtures was designed based on the Proctor method. The influence of the binders on the properties of the HBM road base was evaluated by determining the compressive strength at 7, 14, 28 and 42days of curing, frost resistance and water absorption. The test results were used to optimise the binder composition with respect to the road base characteristics and to establish the recommended road binder composition

This article presents the results of the viscoelastic properties of the polymer-modified bitumen produced in Warm Mix Asphalt technology. A Fischer-Tropsch synthetic wax and a liquid surface-active agent (fatty amine) were used as bitumen viscosity-reducing modifiers. All tested parameters were determined after short-term and long-term ageing. The complex modulus G* and phase angle δ were measured with a cone-plate rheometer. All dynamic tests were performed at 60 °C within the frequency range from 0.005 Hz to 10 Hz. On the basis of the rheological index R determined using the Christensen−Anderson−Marasteanu (CAM) model, it was found that the fatty amine additive slowed down the age-hardening process in the bitumen. In contrast, the synthetic wax increased the stiffness of the bitumen at all levels tested, regardless of the type of ageing simulation process.

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.

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.