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To predict the long-term skid resistance of steel slag asphalt mixtures, accelerated wear tests were conducted using an indoor accelerated loading device on the steel slag asphalt mixtures with different aggregate types, different steel slag blends, and different temperatures. The skid resistance decay law applied to the steel slag asphalt mixture under different influencing factors was investigated. Based on the skid resistance evaluation index measured during testing, a grey residual grey model (GM)(1,1)-Markov model was established to predict skid resistance. The results showed that the incorporation of steel slag significantly improves skid resistance while helping to reduce skid attenuation loss. Skid resistance increased with the increase in steel slag incorporation. With 100% steel slag incorporation, it was optimal. In addition, the test temperature did not change the decay law of the skid resistance index. With changes in temperature, skid resistance showed a decreasing trend. The prediction accuracy of the grey residual GM(1,1)-Markov model was significantly better than that of the grey GM(1,1) model and so can be used for skid resistance prediction. The results of the study can help to determine the attenuation characteristics of skid resistance of steel slag asphalt mixtures, and provide a simple and reliable method for predicting the skid resistance of these mixtures and other pavement aggregates. At the same time, it is certain guidelines for the establishment of the prediction model of asphalt mixture skid resistance under small sample conditions. [ABSTRACT FROM AUTHOR]

On the basis of elastic–plastic theory and generalized Hooke's law, and with the rate effect and random damage characteristics of cement-stabilized steel slag taken into consideration, an elastic–plastic dynamic damage constitutive model of cement-stabilized steel slag under a complex stress state was established in this paper. In the aspect of damage deterioration, the damage evolution equation of cement-stabilized steel slag was established by using statistical theory and introducing the concepts of damage threshold and equivalent plastic strain. With the influence of pore water pressure on materials taken into consideration, Terzaghi's effective stress principle was introduced and the effective stress expression was modified based on the characteristics of cement-stabilized steel slag. With the existence of the ultimate dynamic strength of brittle materials, the S -type dynamic strength criterion of cement-stabilized steel slag was established based on this property. The explicit integral stress return algorithm of the elastic–plastic dynamic damage constitutive model of cement-stabilized steel slag was derived through elastic–plastic theory, and the solving program of the elastic–plastic dynamic damage constitutive model of cement-stabilized steel slag was developed by using the subroutine interface vectorized user defined material (VUMAT) provided by ABAQUS. [ABSTRACT FROM AUTHOR]

The hot deformation characteristics of M50 steel in the temperature range of 900–1150 °C and strain-rate range of 0.01–10 s−1 was investigated in this study using a Gleeble-3800 thermal simulation testing machine. The true stress–strain curves showed that the deformation resistance increased with decreasing deformation temperature, and increasing strain rate before the peak stress was reached. After the peak stress, dynamic reversion occurred, and consequently, the deformation stress decreased. The softening phenomenon was more obvious when the strain rate was low. The calculated values of the thermal deformation-activation energy Q and stress index n were 233,684.2 J/mol and 5.025568, respectively. On this basis, the Arrhenius-type constitutive equation was established, and in addition, a polynomial fit based on strain was performed to obtain the 9th-order strain-compensated constitutive equation with high fitting accuracy. By processing the flow stress curves, the processing maps of M50 steel were constructed, and the optimal processing range was predicted to be in the range of 1070–1150 °C and 0.01–1 s−1. The recrystallization behavior of M50 steel was also studied by constructing a dynamic recrystallization kinetic model and combining optical microscope (OM) and electron backscatter diffraction (EBSD) observation. The results show that with the increase of deformation temperature, the degree of recrystallization transformation increased accordingly, and the original grains were gradually replaced by recrystallized grains. Besides, in the optimal process zone for thermal processing, the recrystallized grains grew with decreasing strain rate and increasing temperature. [ABSTRACT FROM AUTHOR]

The macro- and micro-physical properties of cement-stabilized steel slag (CSS) base materials in a highway project were studied. A discrete element model of CSS with a real steel slag shape was constructed using Particle Flow Code 3D and 3D scanning technology. The sensitivity between the macro- and micro-parameters of the sample was explored, and a nonlinear regression equation was established to analyze the relationship between these parameters. Uniaxial compression simulation tests were conducted on CSS with steel slag contents of 0%, 10%, 30%, and 50%. By combining contact calculation, crack location, energy tracking, acoustic emission (AE) monitoring, and other program systems, the macro- and micro-mechanical properties and micro-crack evolution law of the samples in the failure process were analyzed in terms of strength, energy, and fracture damage. The damage mechanism of CSS was also revealed. Results showed that with the increase in steel slag content, the elastic modulus and peak stress of the samples increased, the Poisson's ratio decreased, and the post-peak stress curve steepened, indicating obvious brittle failure characteristics. With the increase in steel slag content, the crack initiation stress, thickness of the fracture surface, and number of internal micro-cracks in CSS increased exponentially. In the uniaxial compression test, AE intensity underwent five stages, in which the peak moment of AE intensity exhibited hysteresis compared with the moment of the peak stress. Absorption and release phenomena of strain energy were observed in the process of specimen failure. When the steel slag content increased, the total strain energy absorbed by the specimen increased. When the absorbed energy exceeded the bond strength, the bond ruptured with the release of energy. The main crack of the sample penetrated and stretched to the direction of strain energy release to form a macroscopic fracture surface. [Display omitted] • The discrete element model of materials is established by 3D scanning technology. • Porosity is an important factor affecting the mechanical properties of samples. • The crack initiation stress increases from the increase in steel slag content. • There is a hysteresis between acoustic emission event peak and stress peak. • The root cause of material failure is the absorption and dissipation of energy. [ABSTRACT FROM AUTHOR]