TiO₂ and attapulgite (AT) were used to construct micro-/nano-structures, and polydimethylsiloxane (PDMS) was used as a low surface energy material to prepare the superhydrophobic photocatalytic coating (AT/TiO₂@PDMS). The effect of AT amount on the wettability and photocatalytic performance of the coatings was investigated. The results show that the wetting angle of AT/TiO₂@PDMS coating is more than 150° and the contact angle can reach 165° when AT content is 75% (in mass fraction). After exposure to mercury lamp for 11 h, the degradation rate of rhodamine by 25% AT is 94%, and the superhydrophobicity of the coating almost unchanges, indicating that the coating has good photocatalytic activity and anti UV linearity. In addition, the coating has a substrate applicability, which can be applied to various substrates. The wettability on the surface of the coating with some common droplets and acid/alkaline solutions was examined, showing that the coating has a protective effect on these droplets and solutions. The results by Tafel test show that the coating has a good corrosion resistance. Based on the results by self-cleaning and antifouling tests, the coating has a certain cleaning effect and an antifouling performance. In addition, the coating also shows superior flame retardancy and superhydrophobicity after combustion.

Borosilicate glass is currently one of the most widely used matrix materials for high-level liquid waste vitrification due to its advantages of high waste loading, suitable melting temperature, strong adaptability to changes in waste components, radiation resistance and good chemical durability. This review represented recent work on the high-level waste vitrification mechanism of borosilicate glass, key product performance, process performance and economic indicators of borosilicate glass matrix of high-level liquid waste, as well as their engineering applications. This review suggested to carry out the systematic borosilicate glass formulation research in the future and establish the glass formulation design models to meet the vitrification requirements of different types of high-level waste liquids. In addition, the leaching mechanisms and long-term behaviors of borosilicate glass matrix could be also carried out to improve the evaluation criteria for waste glasses.

Stability of foam is one of key factors to determine the comprehensive performance of foamed concrete. However, it is easy to cause coalescence and disproportionation of foams due to the uneven bubble diameter and poor stability of ordinary foam. As a result, the presence of large-sized connected holes will reduce the physical mechanics, thermal insulation and sound insulation properties of foamed concrete. In this review, recent studies on foam in foamed concrete were represented, focusing on three aspects, i.e., foam preparation, foam instability mechanism, bubble stabilization mechanism and measurement.

This paper presented the gradient changes of the characteristics of C(N)-A-S-H (Calcium(Sodium)-Aluminium-Silicate Hydrates) gel in alkali-activated slag (AAS) mortars subjected to sulphate attack in 10% (in mass fraction) MgSO₄ solution by ²⁹Si solid-state magic-angle Spinning nuclear magnetic resonance (SS MAS-NMR), and high-resolution transmission electron microscopy-energy dispersive X-ray spectroscopy (HR TEM-EDX). The results show that the outer layer with the thickness of 0.5-3 mm after attack is mainly composed of Si-Al gel, the middle-level layer with the thickness of 3-6 mm is M/C(N)-A-S-H gel, and the internal layer with the thickness of 6-9 mm is mainly composed of C(N)-A-S-H gel (which was almost not attacked. The stable crystal tobermorite (Ca/Si ratio=0.98) and hydrotalcite-like phase (Mg/Al ratio=2.39) could not be destroyed by sulphate attack. However, the main chain of C(N)-A-S-H gel is readily attacked by sulphate at [AlO₄] bridging tetrahedra (BT). Meanwhile, the magnesium sulphate initially results in de-calcium phenomenon (Mg will replace Ca), and then generates the de-aluminium phenomenon, finally forming the Si-Al gel (main product in the out layer) when removing Ca and partial Al from the gel and charge-balancing the gel by abundant Mg ions.

In order to further improve the mechanical properties of the cement stone with CaSO₄ whisker, the surface of the whisker was modified via tetraethylorthosilicate (TEOS) to improve the interface bonding property between the whisker and the cement stone. The surface composition and properties of the modified CaSO₄ whisker were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, contact angle measurement. The results show that the hydrolysate of TEOS reacts with the hydroxyl groups on the surface of CaSO₄ whisker and forms the stable amorphous SiO₂ on the surface of CaSO₄ whisker. Based on the results by mechanical properties test, the modified CaSO₄ whisker can further improve the mechanical properties of cement. The microstructure of the interface between the whisker and the cement material, the hydration products, the structure of the cement stone, were analyzed by scanning electron microscopy and pore size distribution test, which reveals the action mechanism of modified CaSO₄ whisker reinforced cement. Since SiO₂ coated on the surface of the modified CaSO₄ whisker reacts with the free Ca(OH)₂ in cement-based material, thus promoting the formation of more hydration products, such as calcium silicate hydrate gel chain (C-S-H), as well as makes the whiskers tightly wrapped by hydration products, thus enhancing the bonding effect between the whiskers and cement-based materials and causing more energy consumed during the development of crack. Also, the hydration reaction can improve the compactness of the cement structure, further enhancing the mechanical properties of cement.

A cement-based material with an appropriate amount of carbon nanotubes has a superior piezoresistive effect, which can realize the self-sensing of cement-based composite structure. The piezoresistive effect of carbon nanotube cement-based composite is affected by the material fabric and loading mode, etc.. However, the lack of the corresponding research restricts the development of the intelligent structure of cement-based materials. This review discussed the carbon nanotube content, water cement ratio and carbon nanotube dispersion for the various stages of piezoresistive effect, and analyzed the axial compression, tensile, impact load and impact loading rate, and amplitude.. The characteristics of the piezoresistive effect were pointed out, and the existing problems were given. In addition, the future studies on the piezoresistive effect of carbon nanotubes cement matrix composites were also prospected.

Application of recycled aggregate becomes popular due to the shortage of natural sand and gravel. To improve the technical defects of recycled aggregate mortar, waste rubber particles were used to partially substitute for recycled brick-concrete fine aggregate. The influence of waste rubber particles content on the engineering properties of recycled aggregate mortar at different water-cement ratios was investigated. The consistency, water retentivity and apparent density of the mortar mixture were examined, and the mechanical properties, shrinkage, permeability and frost resistance of the mortar specimens were tested. The results show that the fluidity of the recycled aggregate mortar mixture increases, and the water retentivity decreases as the content of waste rubber particles increases. When the content of waste rubber particles is less than 10%, little decrease in water retentivity appears, while the improvement in fluidity is obvious. The rubber particles with contents of 3%-7% are able to improve the skeleton effect of the aggregate, hence increasing both the flexural and compressive strengths for the mortar specimens. This could be attributed to the elastic deformation of the rubber particles that reduces the stress concentration. When the contents of rubber particles are 3%-7%, the shrinkage resistance, anti-seepage property and frost resistance of the mortar specimens enhance, and these properties increase with increasing the content of waste rubber particles. The amendment of wastes rubber particles has a positive effect on the engineering properties of recycled aggregate mortar.

Ceramic lattice structures have wide application perspectives in the fields of mechanics, electromagnetism, acoustics, thermology. Some approaches fabricating ceramic lattice structures are developed based on the existing additive manufacturing technologies. The unnatural properties of lattice structures can be tailored by designing the structure and arrangement of the cell among the structure. This review represented the additive manufacturing technologies for ceramic lattice structures. Recent development on mechanic-based and function-based ceramic lattice structures was summarized. Some future aspects and challenges for the additive manufactured ceramic lattice structures were also outlooked. This review could provide a guidance for the development of ceramic lattice structures via additive manufacturing.

Porous ceramics are widely applied in catalysts supports, liquid/gas filters, biological scaffolds, thermal isolation and lightweight structural materials due to their low bulk density, high specific surface area, low thermal conductivity, excellent high-temperature resistance as well as corrosion resistance. Hierarchically porous ceramics integrating superiorities of various pore structures have multifunctionalities benefited from pores at different length scales and become the development mainstream of porous ceramics. However, there are still some challenges in the fabrication of hierarchically porous ceramics. Unlike conventional methods that require specific molds and fabricate products with a low forming accuracy, adding raw materials layer by layer with the assistance of additive manufacturing technique can fabricate high-precision products with various complex shapes. The forms of materials before printing include powder, bulk solid, wire and slurry. Compared to powder-based, bulk-based and wire-based additive manufacturing techniques, slurry-based additive manufacturing technique has some advantages of both additive manufacturing technique and colloidal forming method, favoring homogeneously mixing of multi-components, and realizing the fabrication of hierarchically porous ceramics with complex shape and fine microstructure by introducing pores in submicron- or nano-scale via other approaches for porous ceramics. This review represented five types of slurry-based additive manufacturing techniques i.e., stereolithography apparatus, digital light processing, two-photon polymerization, inkjet printing and direct ink writing. Also, hierarchically porous ceramics fabricated by slurry-based additive manufacturing technique with the existing methods for porous ceramics were analyzed. In addition, representative application and future development of the obtained hierarchically porous ceramics based on the slurry-based additive manufacturing technique were also outlined.