For the improvement of the fluidity of castables with recycled aggregates of mullite-SiC bricks due to their high porosity, high water absorption and massive cracks, silica sol was used to impregnate mullite-SiC brick aggregates. The effect of silica sol concentration on the aggregate properties of mullite-SiC bricks was investigated. The microstructures and the element distributions of modified mullite-SiC bricks aggregate were analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy. The water wettability of mullite-SiC brick aggregates was characterized via water contact angle measurement. The results show that after the impregnation of mullite-SiC brick aggregates, the water absorption of mullite-SiC brick aggregate reduces from 6.9% to 2.6%, and the water contact angle decreases from 55° to 7°, thus improving the water wettability of the aggregate. The impregnated mullite-SiC bricks were used as recycled aggregates instead of brown corundum in Al₂O₃-SiC-C castables. In addition, the effect of aggregates on the properties of castables was also investigated. The results indicate that Al₂O₃-SiC-C refractory castables with silica sol concentration of 15% modified mullite-SiC bricks aggregates after heat-treated at 1 450 ℃ have the minimum apparent porosity of 17.1% and the maximum cold compressive strength of 73.7 MPa, which is 45.7% greater than the strength of castables with brown corundum as aggregates. Meanwhile, the residual strength and the residual strength ratio of castables after thermal shock are increased by 69.4% and 24.1%, respectively.

Sulphoaluminate cement is widely used due to its characteristics of short setting time, high early strength, high erosion resistance, low permeability and low-temperature calcination. However, the excessively high cost of raw materials restricts the development/application of sulphoaluminate cement. This review represented recent research work on the use of solid waste to calcinate sulphoaluminate cement clinker, and discussed the effect of calcining process on the appearance of clinker, mineral composition and mechanical properties of cement. Also, the current popular options of solid waste and their feasibility as raw materials for calcining sulphoaluminate cement clinker were introduced. The hydrating capacity of the cement was summarized. The results of the current research were analyzed. The existing problems and development directions were given to provide references for further research and application.

The hydration degree and mechanical properties of ultra-high performance concrete (UHPC) specimens with hybrid steel fibers cured in air and hot water (1 d, 60℃ hot water + 2 d air), respectively, were investigated via ignition loss tests and uniaxial tensile and compressive tests. Also, the surface cracking characteristics of tensile specimens were characterized by digital image correlation technique and optical microscopy, and the microstructures were analyzed by scanning electron microscopy. The results show that compared with the results obtained in air curing, hot water curing accelerates the hydration reaction progress of the UHPC matrix, and an increase in temperature mainly contributes to the promotion of hydration reaction, thus improving the initial cracking, tensile and compressive strength of the UHPC specimens in hot water curing. However, the tensile strain capacity changes slightly. In general, the maximum crack width of the specimen decreases, the matrix becomes denser, and the interface bonding between the fibers and the matrix is stronger. The tensile strain of UHPC increases with the increase of fiber content, in which the tensile strains of the specimens with 2.5% (volume fraction) of fibers (a ratio of long fibers to short fibers is 1.25∶1.25 and 1.5∶1.0, respectively) are more than 2 ×10^-3, the specimen with 1.5% long fibers and 1.0% short fibers produces more tensile cracks with the width of < 50 μm in hot water curing. The uniaxial tensile strains predicted by DIC are in reasonable agreement with the strains measured.

With the developments of the electronics and energy technologies, studies on nanostructure engineering of the emerging thermoelectric materials and thermal logic devices are drawing increasing attentions. In this review, we focus on several promising thermoelectric materials, and study the mechanisms of thermal transport engineering in the atomic and nano-scale structures theoretically and experimentally, with a micro-nano scale thermal transport measurement system developed by our research group. Such research focuses include: the atomic alloying of Si_1-xGe_x alloy films with full components, the mismatched interfaces of Bi₂Ca₂Co₂O_y layered-structure single crystals, the ionic localized resonances of superionic conductor A_0.5RhO₂ (A=K, Rb, Cs) single crystals, and the loose microstructures in quasi-one-dimensional ZrTe₅/HfTe₅ single crystals as well as the SnSe₂ intercalations in SnSe single crystals. The influences of various scale structures and interatomic forces on the thermal transport properties are summarized, offering effective engineering strategies on developing potential thermoelectric materials with low thermal conductivity and excellent thermoelectric performance. Besides, the realization of effective dynamic engineering of thermal conductivity using phase transition, along with its potential applications in thermal logic devices are introduced.

The mechanism of conventional photocatalysis is based on photodegradation effect of photo-induced carrier when the surface of photocatalyst nanoparticles is irradiated by light. For this photocatalysis technique with outside-light-supply mode, a light utilization efficiency is rather low, the catalyst is often out-of-work, and recycle cast is high, which restrict its practical application in environmental protection. To solve the problems above, a photocatalytic system was prepared via the construction of a non-crystal fiber-Sn₃O₄ nanosheet. The results show that Sn₃O₄/optical fiber in the photocslayst can enhance the photocatalytic performance. In addition, the wave guide of incoherent light targeted to photocatalysis and the inner-light-supply photocatalysis were also proposed for the development of optical wave guide theory, and this photocatalyst with Sn₃O₄/optical fiber could have a promising potential in water treatment application.

Phosphosilicate glasses are widely used in optical fiber, biological materials and other fields because of their excellent optical properties and biological activity. The influence of Li₂O content on the microstructure and diffusion properties of Na₂O-Al₂O₃-SiO₂-P₂O₅ glass was investigated via molecular dynamics simulation, and the relationship among the microstructure, Vickers hardness and diffusion coefficient was analyzed. The results show that the degree of phosphorus network polymerization (Q^P) increases with the substitution of Li₂O for Na₂O, and the hardness increases with the increase of Q^P. The self-diffusion of Li⁺ ions is greater than that of Na⁺ ions, indicating that Li⁺ ions are easier to diffuse rather than Na⁺ ions. The potential barrier of Li⁺ ions decreases with the increase of Li₂O. Li₂O is beneficial to the substitution of Na₂O for the diffusion of Li⁺ ions.

To investigate the effects of replacement rate and sample size on the direct shear performance and damage of recycled aggregate concrete (RAC), 45 RAC specimens were manufactured. The failure modes of RAC with different sizes were characterized, and the effects of replacement rate and specimen size on the direct shear performance and damage constitutive model of RAC with different sizes were investigated via direct shear tests. The results show that the peak deformation and ductility coefficient have a size effect, the damage development rate of natural concrete becomes slow, and the damage development rate of RAC becomes faster. The peak deformation firstly decreases and then increases, while the ductility coefficient firstly increases and then decreases with the increase of the replacement rate. The damage development law does not have a linear relationship with the replacement rate. The constitutive model can well reflect the shear load-deformation relationship and the damage evolution process of the RAC with different sizes.

Reinforced concrete structure in a chloride and sulfate coupling environment is vulnerable to be deteriorated due to the combined chloride-sulfate attack. Based on the attack mechanism of chloride and sulfate, this review analyzed the diffusion-binding process of chloride and sulfate ions before and after damage of concrete caused by sulfate attack. Based on the classical diffusion-reaction model and the chemo-damage-transport theoretical framework, the effects of ion activity, temperature, microstructure change and calcium leaching on the chemo-damage-transport system were represented. The coupled transport thermodynamic model of chloride ions and sulfate ions was introduced from the perspective of thermodynamics. In addition, some existing problems in the current research were also prospected.

All-solid-state batteries are considered as one of the most promising next-generation energy storage technologies due to their superiorities of high safety and high energy density. As the core component of all-solid-state batteries, solid-state electrolytes are of great importance for the development of all-solid-state batteries. As a novel family of solid electrolytes, lithium/sodium-rich anti-perovskites have attracted much attention due to their good comprehensive performances. In this review, the latest research progress on lithium(sodium)-rich anti-perovskite solid electrolytes during recent years was represented.

Concrete materials in service are often affected by the coupling action of mechanical and environmental factors. Microcracks inside concrete occur due to the complex stress induced by the combined action of moisture, heat, chemistry and mechanics, promoting the ingress process of water and aggressive ions and further accelerating the durability degradation process of reinforced concrete structures. In order to delay the deterioration of mechanical properties and durability of concrete under severe environments, the self-healing mechanisms of crack within concrete crack through the microbial mineralization technology were investigated. Based on the mechanism of self-healing concrete and regarded the realization mode of microbial healing and its influence on durability of concrete, recent studies on the microbial self-healing of cement-based materials under mineralization were summarized. Finally, the application of different types of microbial-induced calcium carbonate precipitation technology in cement-based materials was represented.