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A distinctive feature of composites is the manifestation of a synergistic effect due to the interaction of contacting substances at the interphase layer, and their intensity of interaction affects the volume properties of the composites. A study of the interphase layer of bitumen was carried out on the surface of the mineral powder. The proposed method according to the results of rheological tests allows calculating the thickness of the boundary layer in the binary system “asphalt – dispersed phase”. The dependence of the road composite strength on the layer thickness of structured asphalt is established: the strength of the composite increases with increasing thickness of the bitumen layer. Method of assessing the impact on the structural-sensitive properties of the composite extensive factor m – indicator reflecting the influence of the interface area and intensive factor n – indicator reflecting the influence of physicochemical effects at the interface is proposed. The extensive factor has a greater effect on the properties of SMA-20 with a quartz filler m/n > 2. There is a higher rate of decrease in the intensity of physicochemical interactions at the interface of the «oil bitumen-silica filler» phase as compared with the extensive factor. The different nature of the effect of temperature on the extensive and intensive factors is observed for SMA-20 with diatomite: as temperature increases, the factor m increases, whereas the opposite effect is observed for factor n. It indicates a positive effect of the specific surface of diatomite on the temperature properties of asphalt concrete.

The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. An increase in the power of industries and vehicles leads not only to atmospheric pollution by-products of incomplete fuel combustion but also to various microscopic particles that form aerosols, which carry an obvious danger to human health and also pollute the buildings’ facades. An environmentally friendly building material with a hybrid method “Nano-titania gradient” was developed. This method consists of forming a gradient of n-TiO2 particles concentration in the composite since the physical properties of the composite are always inextricably linked to the geometry. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide with the use of graphene oxide was proposed, which contributed to an increase in the overall photosensitivity. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning is completed after 3 h after the irradiation start. The modern rhythm of human life leads to well-known problems, which are air, water and soil pollution and climate warming. Using the theory of percolation, the concentration range of the photocatalyst content was calculated. To facilitate the material, waste cellulose was introduced. To increase the efficiency of the photocatalytic process, a method of surface sensitization of titanium dioxide (SS TiO2) with the use of graphene oxide was proposed. The analysis of the experimental-statistical models of the compressive strength shows that the optimum content of TiO2 was in the range from 0.8 to 1.1%, and cellulose from 0.4 to 0.8%, the optimum content of SS TiO2 was in the range from 0.7 to 1.1%, and cellulose from 0.4 to 0.8%. Analysis of the experimental and statistical model of the bending strength shows that the optimal content of TiO2 and SS TiO2 was in the range of 0.6 to 1.0%, and cellulose from 0.4 to 0.8%. When studying the structure of composites, it was found that titanium dioxide was sorbed on the surface of swollen cellulose fibers and remained there after the process of cement hydration. The effectiveness of the method of surface sensitization of titanium dioxide by combining it with graphene oxide was shown. Thus, the decomposition of nitrogen oxide by volume with the modified surface increased by 27% in comparison with the classic titanium dioxide, and the decomposition of volatile organic substances increased by 32%. It was found that for the facade plate made with surface-sensitized TiO2, the process of self-cleaning was completed after 3 h after the irradiation start.

The formation of sustainable concrete is directly relaed to the intensity of the processes occurring at the interface of phases. The study of the surface properties of CNPLUS carbon nanotubes in solutions of various plasticizers was carried out by measuring and calculating adsorption. The applicability of the adsorption value is for forecasting both the efficiency of dispersion and aggregative and sedimentative stability of the obtained dispersion systems. It was stated that two-dimensional pressure arising at the interface of adsorption layers in the dispersive medium with the surfactant Tensafor 2553.2 J/m2 is sufficient to overcome adhesive strength on a small area of the localized contact of carbon nanoparticles CNPLUS, which explains the peptization and stabilization of the particles’ surface. It was established that full stabilization of nanoparticles in the aqueous dispersive medium could be ensured only by means of soap-like surfactants, with the compound potassium naphthalene sulfonate (Tensafor). It ensures formation of the micelle-like structure in coagulation layers that forms a structural and mechanical barrier with the external hydrophilic surface. This leads to the increase in the ultimate tensile strength of the concrete grout specimens by 38%.

The objective is to propose a new methodology of modulus backcalculation and analyse its rationality and feasibility. Firstly, the features and advantages of the proposed are summarised. Secondly, a total of 130 sets of deflection basinswere collected and the modulus was backcalculated. Meanwhile, the temperatures of different asphalt layers were monitored. Subsequently, the simple performance test (SPT) was used to establish the master curve model. The dynamic modulus of different asphalt mixtures of falling weight deflector's load frequency and real test temperature was predicted. Following, the backcalculated modulus was compared with the SPT modulus for verifying its ability of reflecting the material properties. Furthermore, the rationality of the backcalculated modulus is verified, as well as its ability to distinguish between different sections. Lastly, the efficiency, success rate and stability of the proposed method are statistically analysed. Results show that the ratios of the backcalculated modulus to the SPT modulus range from 0.9 to 1.2. The proposed method can process about 100 measured deflection basins per minute and its success rate exceeds 80%. The coefficient of variation of the effective modulus does not exceed 15%. The proposed method has high rationality and feasibility meeting the requirements of engineering applications. [ABSTRACT FROM AUTHOR]

Asphalt rubber (AR), which is prepared by blending crumb rubber and bitumen, provides various advantages, including superior rutting resistance, lower road-tire noise and longer service life. However, contractors have expressed concerns regarding its poor storage stability, which in turn limits its wider application. This study aims to address the storage stability concern by incorporating nano-montmorillonite (nanoclay). Three types of nanoclay were dispersed into hot AR binder by high shear blending. The rheological properties of nanoclay-crumb rubber modifier (CRM)-modified bitumen were evaluated through Superpave performance grade (PG) tests and the storage stability was characterized by measuring the difference in softening points or complex moduli at the top and bottom portions of binders after lab-simulated storage. X-ray diffraction (XRD) evaluation was conducted to observe the variation of nanoclay layer gap distance for mechanism investigation. It was found that all selected nanoclays had insignificant effects on workability, rutting and fatigue properties. The layered nanoclay transformed to intercalated or exfoliated structures after interaction with bitumen fractions, providing superior storage stability. Among the three selected nanoclays, pure montmorillonite with Na+ inorganic group, which has an intermediate hydrophilic property and middle layer gap, showed the most obvious effect on enhancing the storage stability of AR. [ABSTRACT FROM AUTHOR]