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Ultrahigh-temperature ceramics were added to C/C composites to meet their application requirement in a high-temperature oxidizing environment. C/C−ZrB2−SiC composites were fabricated by high-solid-loading slurry impregnation with polymer infiltration and pyrolysis. The dispersion and rheological behavior of ZrB2 slurry and the microstructural, mechanical, and ablation properties of the C/C−ZrB2−SiC composites were investigated. Results indicated that a well-dispersed and low-viscosity ZrB2 slurry was obtained using 0.40 wt.% polyethyleneimine as a dispersant at pH 5. Ceramics were uniformly distributed in the short-cut fiber layer and needle-punched area. The flexural strength of the C/C−ZrB2−SiC composites was 309.30 MPa. The composites exhibited satisfactory ablation resistance under the oxyacetylene flame of 2500 °C, and the mass and linear ablation rates were 0.40 mg/s and 0.91 μm/s, respectively. A continuous and compact ZrO2 layer, which could effectively reduce the diffusion rate of oxygen and protect the composites from being ablated, was formed.

ZnFe2O4 hollow spheres (ZFHs) with sizes of 200–302 nm were synthesized by simple impregnating method using the as-prepared phenolic formaldehyde (PF) spheres as templates and subsequent annealing at 500–700 °C. The prepared ZFHs are assembled by a large number of small nanoparticles with sizes of 15–20 nm, and many mesopores exist among these nanoparticles. The samples annealed at 500–550 °C exhibit a single cubic spinel structure, while higher annealing temperature leads to the formation of hexagonal ZnO and rhombohedral α-Fe2O3 secondary phases. The size of the assembled nanoparticles increases with the increase in annealing temperature. Novel magnetic transformation from paramagnetic to ferrimagnetic is induced by the reduction of annealing temperature and the saturation magnetization significantly increases from 2.3 to 13.5 A·m2/kg. The effect of the formation of hollow sphere structure on the redistribution of Fe3+ and Zn2+ in the spinel structure was studied.

NanoSiO2 was widely used to modify the property of cementitious materials, however, for nanoparticles used in cement-based materials, key problem is the effective dispersion. The surface modification technology can be introduced to promote dispersion of nanoparticles in aqueous system, especially in cement pore solution, which possess high concentration of ions. In this study, at first, NanoSiO2-polycarboxylate superplasticizer (SiO2-PCE) core-shell nanoparticle was synthesized from silanized polycarboxylate superplasticizer and colloidal nanoSiO2 by the “grafting to” method, then SiO2-PCE was testified by UV-Vis, FTIR, and TGA. Additionally, stability of SiO2-PCE and its effect on cement hydration were investigated. Results shows: SiO2-PCE possess higher stability in saturated calcium hydroxide solution compared to nanoSiO2, and heat development of cement hydration can be regulated by shell structure of SiO2-PCE. The research implied a new approach for nanoSiO2 to optimize cement-based composites.

Carbon/carbon–copper(C/C–Cu) composites are fabricated by infiltration of Cu into Mo2C interlayer-modified carbon/carbon(C/C) preforms. Effect of graphitization on the microstructure and properties of the C/C–Cu composites is studied. The C/C–Cu composite with graphitization shows lower electrical resistivity, thermal expansion coefficient, friction coefficient, and an obvious higher thermal conductivity due to higher graphitization degree. However, it presents lower flexural strength, impact toughness, and higher wear rate. The composite with graphitization exhibits mainly abrasive wear while that without graphitization exhibits mainly adhesion wear, and both composites show oxidation wear.

Carbon/carbon–copper(C/C-Cu) composites were fabricated by pressure-less infiltration of Cu into carbon/carbon (C/C) preforms modified with Mo2C interlayer by a molten salt method. Cu filled the pores inside the Mo2C-modified preforms fully, and retained an interconnected net-like distribution in the C/C-Cu composites. The electrical resistivity and flexural strength increased, whereas impact toughness decreased with the increase of preform density. Fiber pull-out and crack propagation along the interface contributed to the pseudo-plastic behavior of the composites. The tribological performance was improved with the increase of preform density due to the better lubrication of transfer films.

A carbon/carbon–ZrC(C/C–ZrC) composite was fabricated by reactive infiltration of a Zr–40 wt% Cu powder mixture. The C/C–ZrC composite was composed of C, ZrC, and residual Cu. Continuous ZrC layers around the pyrolytic carbon and isolated ZrC particles dispersed in Cu were detected. Linear ablation rate of the composite increased with the increase of ablation time. Ablation surface of the composite was mainly composed of monoclinic ZrO2, while the quantity of Cu and Cu2O decreased with the increase of ablation time. The better ablation resistance of the C/C–ZrC composite was mainly attributed to the protective ZrO2 layer and the cooling effect of Cu.

Surface segregation of asphalt mixtures is a common problem encountered when determining segregation level, which is a criterion of pavement quality evaluation. A method to evaluate segregation levels of asphalt pavement surface was presented based on the concave multifractal characteristic in a binary image of a pavement surface, which was obtained by digital image processing technology and mathematical morphology. The practical value of the proposed method was verified in a newly built asphalt pavement, and the segregation level was divided into five sections based on the recommended texture ratio in practical engineering. Results show that the multifractal spectrum width (Δα) quantifies the uniformity of the concave distribution. The pixel percentage of the concave (P) characterizes the ratio of the occupied area. The product of Δα and P (PWP) was quantified as the surface segregation level, which has good linear relevance with texture depth evaluation results. The proposed evaluation technique (PWP) can be used as an alternative to the sand patch method.