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To accurately determine the wax precipitation temperature (WPT) of wax-based warm mix asphalt binder, a novel algorithm for WPT calculation was proposed, and the process of wax precipitation in asphalt, as well as the effects of aging, cooling rate, and shear rate on wax precipitation characteristics, were investigated through dynamic shear rheometer (DSR) tests and polarised light microscopy (PLM) experiments. The research findings reveal the following: The refined WPT algorithm exhibits heightened precision compared to the traditional viscosity method, showcasing superior reproducibility and mitigating human-induced errors. During the cooling process, wax molecules become oversaturated, leading to the precipitation of wax crystals and the transformation of asphalt into a solid–liquid two-phase system. The aging of asphalt causes changes in its composition, shifting the phase equilibrium towards favouring wax precipitation. The WPT of asphalt is also influenced by the cooling rate and shear rate, and a larger cooling rate and shear rate will reduce the WPT. Wax crystals are less numerous and more regular in shape at low cooling rates. [ABSTRACT FROM AUTHOR]

To promote the large-scale application of steel slag in road base, firstly, the process of steel slag standard system in road base was summarized, and the risks of steel slag volume expansion and heavy metal leaching were analyzed. Then, the pavement performance of cement stabilized steel slag macadam, cement fly ash stabilized steel slag macadam and lime fly ash steel slag macadam were comprehensively investigated. Finally, the application status and existing problems of steel slag base course were introduced. The results show that the volume stability of solidified steel slag can be improved by admixture method, and the content of active material can be controlled from the source by process method and melting tempering method. There is a risk of heavy metal leaching in steel slag, so the detection of raw materials of steel slag should be strengthened and special design should be carried out to avoid rainwater infiltration into the base. In general, the steel slag mixed into the base course mixture can improve the mechanical properties, significantly reduce the drying shrinkage, increase the crack resistance, and enhance the anti-scouring and anti-fatigue performance of cement stabilized steel slag macadam. The application of steel slag base course is in the exploration stage of paving test section. In future, research on steel slag based multi-source solid waste materials, steel slag base course complete technology and application policy guarantee system of steel slag should be conducted. [ABSTRACT FROM AUTHOR]

The permeability coefficient of concrete was tested by self-made falling water test device, and the relationship between porosity and permeability coefficient was analyzed. Based on the design of plugging test, the influence of different particle size blockers on concrete plugging and the plugging process of yellow mud that is sticky on concrete were studied. The results demonstrate that there is a high linear relationship between the porosity and the permeability coefficient; when facing the same size of blocker. the anti-clogging ability of concrete with different voids is different, the size of blockage sensitive particle of concrete with 15% porosity is 0.15~0.3 mm and 0.3~0.6 mm, while that of concrete with 20% and 25% porosity is 0.3~0.6 mm and 0.6~1.18 mm; the concrete with different voids was blocked seriously by graded gravel, the sticky blocker such as yellow mud would lead to the rapid plugging of permeable concrete. [ABSTRACT FROM AUTHOR]

In order to analyze the rationality of evaluation indexes HI1, HI2, HI3, HI4 and HI5 based on rheological properties for self-healing performance of asphalt, DSR (dynamic shear rheometer) is used to test the relationship between the complex modulus and loading times of virgin asphalt, SBS modified asphalt and rubber modified asphalt. Based on four-point bending fatigue test, the fatigue-self-healing properties of virgin asphalt mixture, SBS modified asphalt mixture and rubber modified asphalt mixture are studied. The results demonstrate that evaluate the self-healing performance of asphalt with different indicators may obtain different results, the order of self-healing ability of virgin asphalt, SBS modified asphalt and rubber modified asphalt is inconsistent, and the evaluation result of HI5 index on self-healing ability of three asphalts is consistent with mixtures, the self-healing ability of rubber modified asphalt and SBS modified asphalt is better than virgin asphalt obviously. [ABSTRACT FROM AUTHOR]

In this paper, fluorescence microscope was used to analyze microstructure of A-70' asphalt, SBS modified asphalt and rubber modified asphalt, and DSR was used to test and evaluate self-healing properties. The results show that the higher the temperature is, the more the SBS modifier, rubber powder and matrix asphalt tend to be phase soluble, and the solubility of SBS and 70' asphalt is better than that of rubber powder. The self-healing capacity of SBS modified asphalt and rubber modified asphalt is comparable and better than that of A-70' road petroleum asphalt. The self-healing property of asphalt material is inversely proportional to the degree of injury. The greater the degree of injury, the less significant the self-healing ability. The self-healing energy barrier of rubber modified asphalt is the largest, followed by SBS modified asphalt, and 70' asphalt is the smallest. The self-healing effect of rubber asphalt requires higher temperature conditions and heat supply. [ABSTRACT FROM AUTHOR]