Fe₃O₄@calcium silicate hydrate (CSH) nanosheets composite adsorbents were obtained through electrostatic interaction. And an "adsorbent-to-photocatalyst" transformation strategy was proposed: the harmful heavy metal ions from the polluted water were removed by Fe₃O₄@CSH adsorbents, after which they were recycled and reused as photocatalysts for CO₂ reduction. The results demonstrated that: benefiting from ultrahigh surface area and strong ion exchange ability of CSH nanosheets, heavy metal ions including Zn²⁺, Cu²⁺, Co²⁺, Ni²⁺, and Pb²⁺ could be efficiently removed by Fe₃O₄@CSH adsorbents. The maximal adsorption capacities were 83, 142, 150, 179, 343 mg/g, respectively. Fe₃O₄@CSH adsorbents containing heavy metal ions could efficiently reduce CO₂ to CO under visible light. Particularly, Fe₃O₄@CSH-Ni after adsorption of Ni²⁺ showed the best catalytic activity. The CO generation rate was up to 3 310 μmol/(g·h) with a high selectivity of 99.3%. Besides, the magnetic property of Fe₃O₄ enabled the rapid recovery of Fe₃O₄@CSH during the adsorption and photocatalysis processes.

A series of graphitic carbon nitride (g-C₃N₄) nanosheets with controllable thicknesses were prepared by a thermal polymerization method with different ratios of precursor melamine and urea. The nanosheets were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, specific surface area measurement, ultraviolet-visible spectroscopy and photoluminescence, respectively, which were used for the photocatalytic degradation of Rhodamine B (RhB). The results show that g-C₃N₄ is the thinnest (1∶8-CN) with the thickness of 3.5 nm when the ratio of melamine to urea is 1∶8. Its specific surface area is 6 times greater than that of g-C₃N₄ prepared using only melamine (assigned as M-CN). The photoelectric analysis indicates that 1∶8-CN has a higher separation efficiency of photogenerated carriers. Under the visible-light, the photocatalytic degradation rate of RhB by 1∶8-CN can reach 96.2%, which is 1.9 times greater than that of M-CN. Besides, the photocatalytic degradation mechanism of 1∶8-CN toward RhB is since the electrons generated by the separation of photogenerated electron-hole pairs combine with O₂ to generate·O₂^-, and then·O₂^- oxidizes RhB into CO₂ and H₂O, and the holes do hardly participate in the reaction.

Geological polymer (zinc slag/Metakaolin geopolymer, ZMG) was synthesized by using zinc slag and metakaolin as raw materials and phosphoric acid as activating agent. The effects of the ratio of raw materials on the mechanical properties, formation of mineral phases, microstructure and pore size distribution of geopolymers were studied. The geopolymer was employed as Fenton-like catalyst for degradation of direct copper salt blue 2R simulated dye wastewater. The effects of the ratio of raw materials, catalyst dosage, pH value and H₂O₂ concentration on dye degradation rate were systematically investigated. The results showed that the 7-day compressive strength of ZMG-50 geological polymer with a zinc slag proportion of 50% (in mass fraction) could reach 19.9 MPa. Zinc slag can eliminate mechanical pores, improve mesoporous structure and increase specific surface area of geopolymer. The catalytic results showed that ZMG-50 had the best catalytic performance under the conditions of catalyst dosage of 8 g/L, pH value of 2.5 and H₂O₂ concentration of 0.32 mmol/L, the degradation rate of direct copper salt blue 2R dye could reach 96.2% after 42 min reaction, and it had good stability and reuse performance.

Octahedral cations of acid-treated palygorskite clay (Pal) were partially replaced by Cu²⁺ via hydrothermal method to achieve lattice reconstruction (Cu-Pal). CuO quantum dots (CuO QDs) were grown in situ on the surface of Cu-Pal by adjust the pH and thermal treatment in case of excess Cu²⁺, which led to the formation of CuO QDs/Cu-Pal nanocomposite toward photocatalytic nitrogen fixation. The influence of Cu²⁺ content on the microstructure, optical property and band gap structure of Pal were studied. Results showed that the Cu substitution narrowed the band gap of Pal which extended the light response range from ultraviolet light to visible light. When the Cu²⁺ content exceeded 5% (in mass fraction), CuO QDs on the Cu-Pal surface effectively promoted the absorption of NIR light due to its rather low band gap (1.2 eV). 20% Cu-Pal formed the best-matched Type-I heterostructure and demonstrated the highest photocatalytic nitrogen fixation performance due to the enhanced charge separation.

Attapulgite and wollastonite powders modified by a mechanochemical method were added to polytetrafluoroethylene (PTFE), and then the mineral/polymer composite was prepared by mechanical stirring and cold pressing sintering. The physical and chemical properties, friction and wear characteristics of the composite were investigated X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetry-differential scanning calorimetry, polarized microscopy, X-ray photoelectron spectroscopy, Shore hardness test and ring block friction and wear test, respectively. The results show that the crystallinity and glass transition temperature of the PTFE composite decrease, the hardness increases, the friction coefficient increases slightly, and the wear rate decreases significantly after adding attapulgite and wollastonite into the composite. It is indicated that attapulgite and wollastonite are beneficial to the formation of the transfer film on the surface of the metal friction pair, thus effectively improving the self-adaptability of the friction interface between the PTFE composite and the counter metal friction pair and reducing the wear rate of the friction pair.

Clustered crystals of Silicalite-1 forming spherical-like structures were synthesized by a solvent-free solid-state method using activated carbon as a hard template. The influence of activated carbon dosage on the Silicalite-1 zeolite was explored by X-ray diffraction, specific surface area analysis, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, and X-ray photoelectric spectroscopy. The results show that the C—O—Si bond is formed between hydroxyl groups on the surface of activated carbon and silicic acid, growing and aggregating along the activated carbon and formed spherical-like Silicalite-1 zeolites after calcination. The spherical-like Silicalite-1 prepared with 10% (in mass fraction) activated carbon has a greater crystallinity with great specific surface area and pore volume as well as uniform particle size.

The integrity of the seed layer was improved by adding SiO₂-ZrO₂ nano-sized sol into the seed solution on macroporous α-Al₂O₃ carrier for the preparation of high-performance mordenite membranes. The effect of SiO₂-ZrO₂ sol amount added in the seed crystal on the seed layer and zeolite membrane was investigated. The results show that the pervaporation performance of mordenite membranes is improved by the addition of SiO₂-ZrO₂ sols. The flux and separation factor decreases slightly as the concentration increases. When 0.5% (in mass fraction) SiO₂-ZrO₂ sol is added into the seed crystal, the permeation flux and separation factor can reach 0.94 kg/(m²·h) and 5 285 by a pervaporation of 90% (in mass fraction) acetic acid/water solution at 75℃. It is indicated that SiO₂-ZrO₂ sol improves the dispersion of the seed in the solution. The mordenite membrane prepared by this method has good repeatability and acid resistance.

Cation exchange capacity (CEC) is an essential physicochemical index of clayey soil, which can characterize the physicomechanical properties of clayey soil, and methylene blue method can quickly determine the CEC of clayey soil. Therefore, methylene blue method (MB method), ammonium chloride ammonia water exchange method (ammonia method), and barium chloride buffer method (barium method) were used to measure the CEC of several typical clayey soils, to explore the applicability of MB method. The results show that the ammonia method and barium method are consistent, but MB method is different from ammonia method and barium method; The test result is low when the CEC is low, and the test result is high when the CEC is high. The adsorption behavior of methylene blue to clayey soil was analyzed by X ray diffraction test, which was found that methylene blue molecules were adsorbed on the surface when the CEC was lower (less than 40mmol/100g); When the CEC was higher (greater than 40 mmol/100 g), a large number of methylene blue molecules were absorbed between layers. Combined with the results of X ray diffraction, the results of the MB method are modified by the change of basal spacing (d₀₀₁). The results of the MB method are modified by empirical relation at low CEC and modified by d₀₀₁ at high CEC, and good results are obtained.

A SiO@TiO₂/C composite was synthesized by a sol-gel method and a subsequent high-temperature solid-phase method. The results show that SiO@TiO₂/C material exhibits an excellent cycling and rating performance due to the promotion of TiO₂ on the interface stability and lithium-ion diffusion process. A high specific capacity of 710 mA·h/g is achieved after 150 cycles at a current density of 1 A/g, and the reversible capacity is 430 mA·h/g at a high current density of 4 A/g.

Si/C@graphene(GR)/graphite(G) composite anode materials were prepared by a simple and easy-to-operate wet coating method with silicon nanoparticles and graphite as main raw materials, fatty alcohol polyoxyethylene ether as a surfactant and graphene. The effect of allocation ratio on the composition, morphology and electrochemical performance of the composite materials was investigated. The results show that the prepared composite materials exhibit a superior cycling stability, and the volume expansion alleviates. When the silicon nanoparticles content is 10%, the initial discharge capacity is approximately 730 mA·h/g. After 100 cycles at a current density of 100 mA/g, the discharge capacity can stably maintain at 500 mA·h/g. The initial coulomb efficiency reaches 87.27%, revealing a great improvement in comparison with the efficiency of pure silicon material (i.e., less than 70%).

This review represented recent work on minerals application in electrochemical energy storage, i.e., the use of minerals in electrodes, electrolytes and separators of secondary batteries or supercapacitors. In addition, the existing problems, challenges and future development in this field were also described.

Different amounts of NaH₂PO₂ were used to treat lithium-rich cathode materials. The results show that the material treated by 4% (in mass fraction) NaH₂PO₂ exhibits an excellent cycle stability with 85.3% of capacity retention after 150 cycles at 0.5 C and a high Coulombic efficiency. The enhanced electrochemical performance is attributed to the two following aspects. One aspect is that NaH₂PO₂ pyrolysis produces reducing PH₃ gas, which reacts with the active oxygen in the surface layer of the lithium-rich cathode materials to yield oxygen vacancy, thus effectively reducing the irreversible capacity loss in the first charge process. Another is that NaH₂PO₂ pyrolysis treatment induces Na⁺ doping, which can effectively stabilize the lattice structure and inhibit phase transition, and accelerate Li⁺ diffusion and reduce the electrochemical impedance. In addition, the formed Na₄P₂O₇ coating can protect the electrode material and reduce the dissolution of the transition metal, thereby improving the cycle stability.

Diamond-like-carbon (DLC)/N-gradient CN_x nano-multilayer films with different thicknesses of nitrogen-content gradient CN_x layers were prepared on silicon substrate via direct-current magnetron sputtering, in which the nitrogen-content gradient appears in an inverted "U" shape. The microstructure, surface morphology, mechanical and tribological properties in vacuum and air were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scratch testing and ball-on-disk wear tests. The results show that the surface of the multilayer films is smooth and all of them are amorphous. The hardness, elastic modulus, and adhesion of the multilayer films gradually decrease, and the surface roughness and wear rate increase with the increase of N-content gradient CN_x layer thickness. The wear resistance of the multilayer films is better in vacuum rather than in air. The multilayer film with a CN_x layer thickness of less than 30 nm exhibits a hardness in the range of 21.9-23.1 GPa, an interface adhesion in the range of 54.2-54.3 N, a friction coefficient of approximately 0.19 in air and 0.18 in vacuum, and a wear rate in the range of (0.98-1.16)×10^-16 m³/(N·m) in air and (0.83-0.88)×10^-16 m³/(N·m) in vacuum.

Fe₃O₄/CS carbon aerogel electrode material with a high specific capacitance was prepared via in-situ growth with chitosan (CS) and FeCl₃·6H₂O as raw materials. The crystal structure and structural defects of the samples were analyzed by X-ray diffraction and Raman spectroscopy, and the composition and morphology were characterized by X-ray photoelectron spectroscopy and scanning electron microscopy, and their electrochemical properties were tested in a three-electrode system. The results show that Fe₃O₄ can be loaded on the CS carbon aerogel with their effective bonding. The amino groups on the chitosan molecules achieve self-doping of N atoms during the carbonization process, and the N content of the composite is as high as 7.21% (mole fraction). In addition, the composite carbon aerogel exhibits a high specific capacitance of 315.5 F/g at a current density of 0.5 A/g when introducing 0.4 g FeCl₃·6H₂O into 1.0 g CS. The specific capacitance of the composite carbon aerogel is approximately 3 times greater than that of original chitosan carbon aerogel.

The boron-doped mesoporous carbon (BMCs) and boron-doped graphene-based mesoporous carbon (BMC/GO) were synthesized by a solvent evaporation-induced self-assembly method with block copolymer F127 as a soft template, boric acid as a boron source, phenolic resin prepolymer carbon sources and graphene-oxide (GO) as modifiers. The structures of the materials were characterized by transmission electronic microscopy, X-ray diffrication, nitrogen adsorption-desorption, and X-ray photoelectric microscopy. The electrochemical properties of samples were tested by electrochemical workstation. The structural characterization shows that the as-prepared composite material BMC/GO-40 (the mass of GO suspension is 40%) exhibits a great specific surface areas (i.e., 462.5 m²/g), and the average pore size is approximately 5 nm. The boron element mainly exists in the framework of mesoporous carbon in two forms, i.e., BC₃ bonding and BCO₂/BC₂O bonding. Based on the results by electrochemical tests, the maximum specific capacitance can be obtained via the addition of an appropriate amount of boron doping and the adjustment of the composite amount of graphene oxide. The capacity of BMC/GO-40 sample is 167 F/g at a current density of 0.5 A/g.

The relationship between the Weibull modulus of bending strength and its thickness of single cell before and after reduction was investigated by a coaxial ring force method. The Weibull modulus of NiO-YSZ anode supported cell is 4.56, 4.78 and 6.16 for the thickness of 1.1 mm, 0.9 mm and 0.7 mm, respectively. The Weibull modulus increases gradually with the decrease of sample thickness due to the reduced internal defect number of anode. The Weibull modulus of Ni-YSZ anode supported cell increases to 8.66, 12.49 and 9.37, respectively, since a plastic Ni phase inhibits the crack propagation. The single cell with a thickness of 0.9 mm shows a greater performance with the corresponding bending strength of 122.9 MPa. The crack sources of the sample mainly come from the internal defects of the anode and the agglomeration of Ni particles. Based on the experimental results, the influence of single cell thickness on its mechanical properties can be demonstrated at different crack source types and fracture modes.

The La_0.5Sr_0.5CoO₃(LSCO) oxide bottom electrodes were epitaxially grown on (001) SrTiO₃(STO) substrates via off-axis magnetron sputtering at different deposition temperatures. Based on the results of X ray diffraction (XRD), atomic force microscopy (AFM) and four probe square resistance test, the optimal deposition temperature for (00l) epitaxial LSCO films is 550℃. In addition, the Pt/Na_0.5Bi_0.5TiO₃(NBT)/LSCO/STO ferroelectric capacitor was fabricated on LSCO/STO heterostructure via laser pulse deposition. The results indicate that NBT films are (00l) epitaxial. The leakage current density of Pt/NBT/LSCO heterostructure increases with increasing temperature from room temperature to 70℃. The conduction mechanism is ohmic conduction at low voltage and space charge limited current at a high voltage. At 5 V driving voltage, the Pt/NBT/LSCO capacitor exhibits saturated hysteresis loops and retention characteristics both at room temperature and 70℃ without fatigue after 10¹⁰ inversion.

Conventional energy storage devices often need to be replaced or wired for charging due to their limited capacity, which is difficult to meet the working demands of wearable electronic devices in some special occasions. Using the "piezoelectric effect" of piezoelectric materials to construct a piezoelectric self-chargeable energy storage device based on the conversion of force to electricity is an effective solution to the problem s above. Recent development on the piezoelectric and self-chargeable energy storage devices was reviewed. In addition, the design principle, characteristics, construction base and applications were also introduced.

The core-shell composites (FeCo@TiO₂, FeCo@TiO₂@Fe₃O₄) were fabricated via hydrolysis reactions with flattened FeCo as the core and TiO₂ and Fe₃O₄ as the shell. The morphology and phase composition of the core-shell composites (i.e., FeCo@TiO₂, FeCo@TiO₂@Fe₃O₄) were characterized by scanning electron microscopy and X-ray diffraction. The results show that the core-shell composite is flattened with diameters of 20-50 μm and thicknesses of 3-5 μm. The main components of the coating layer are TiO₂ and Fe₃O₄, which are uniformly distributed on the flattened FeCo core. The complex permittivity and permeability of the samples were measured in a frequency range of 2~18 GHz, and the reflection loss of the samples was calculated based on the transmission line theory. It is indicated that the effective absorption bandwidth of the FeCo@TiO₂@Fe₃O₄ samples at room temperature is 3 GHz (RL<-10 dB) with the thickness of 2.5mm, and the minimum reflection loss of the sample is -35.4 dB. The effective absorption bandwidth is 2GHz, and the minimum RL value is -29.2 dB after annealing at 500℃. The thermogravimetric analysis indicates that the weight gain of FeCo@TiO₂@Fe₃O₄ is 20% less than that of FeCo at 800℃.

Fe@(ZnO/C) composite was prepared with resorcinol, zinc acetate dihydrate and ferrous sulfate heptahydrate by a wet chemical method and a subsequent high-temperature heat treatment. The results show that Fe@(ZnO/C) ternary composite with a ball-chain Fe powder has a better impedance matching and a higher attenuation coefficient, showing a superior electromagnetic wave absorption performance. The optimum reflection loss () is -56.01 dB at 10.91 GHz with a thickness of 2.73 mm and the effective absorption bandwidth () is up to 5 GHz (i.e., 8.54-13.54 GHz).

The transition metals (i.e., Co, Mn) supported rod-like CeO₂ nanomaterials with different proportions were prepared by an one-step hydrothermal method. The influence of transition metals (Co, Mn) content on the crystal lattice constant, element content of different valence states of the catalyst, specific surface area and CO catalytic oxidation performance were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron microscopy, specific surface area analysis, H₂-temperature programmed reduction and CO-temperature programmed desorption, respectively. In addition, compared to pure CeO₂, CeO₂ nanorods supported Co or Mn show a greater catalytic activity for CO at a low temperature. The temperature range of Co-CeO₂ with catalytic oxidation CO of 50% (T_50%) is 97-133℃, and that of Mn-CeO₂ is 107-195℃. Co-CeO₂ and Mn-CeO₂ with 40% (in mole fraction) of Co or Mn show the optimum catalytic performance, and the T_50% of 40% Co-CeO₂ is 97℃ and 40% Mn-CeO₂ is 107℃, respectively. The introduction of transition metal (Co, Mn) enhances the synergistic effect on the catalyst surface and produced more active oxygen, thus effectively enhancing the catalytic oxidation performance of the nanomaterials.

Fumed silica and polydimethylsiloxane were mixed with water to prepare a suspension with a certain viscosity. The three-dimensional aggregates of fumed silica nanoparticles in the spraying process were used to form a micro-/nano-grade rough structure for super-hydrophobic coating, and a low surface energy material of polydimethylsiloxane was stored in the three-dimensional pores of gas-phase chain silica nanoparticles, and self-healing superhydrophobic coatings were prepared via simple spraying on the surface of different substrates. After the surface of the coating is destroyed by oxygen plasma, the coating can be restored to its super-hydrophobic performance by only placing at room temperature or treating at 100℃ for 30 min. The number of self-healing exceeds 20 times. Also, the coating has good high-temperature resistance, acid and alkali resistance, friction resistance and erosion resistance performance.

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.