Magnetizing roasting of oolitic hematite ore from western Hubei Province was investigated. The mechanism for reduction roasting of oolitic hematite ore was discussed and analyzed. It is found that flash magnetizing roasting-magnetic separation process is a promising approach for the processing of oolitic hematite ore from western Hubei Province.

The nose temperature for σ-phase precipitation in super-duplex stainless steel (SDSS) UNS S32750 was evaluated by hardness method. Color-optical microscopy, scanning electron microscopy, energy spectrum analysis, impact and corrosion testing were carried out to investigate characteristics of microstructure and properties of the SDSS aged at the nose temperature. The experimental results indicate that the nose temperature of precipitation is 920 °C and aging at this temperature tiny σ phases can precipitate at phase interfaces or ferrite grain boundaries within 2 min. Prolonging aging duration the amount of σ-phase increases and a dual structure with σ and γ is obtained when aging for 120 min. The precipitation of σ-phase leads to severe deterioration in impact toughness (longitudinal/transverse direction) and corrosion resistance of SDSS.

The effects of strain rate on the dislocation type and dislocation configure of TA15 alloy were investigated. The experimental results show that the operating dislocation type changes from $\bar c$ type to $\bar c$ and $\bar a + \bar c$ type with increasing strain rate under the deformation condition of 900 °C, 60% strain. Under the condition of 900 °C, 60% strain and 0.001/s strain rate, lots of orientate dislocation cellular configurations and sub-grains, many dislocations pile up before sub boundary. When the strain rate increases to 0.1/s, some dislocations exhibit curved and dislocation tangles and pile-ups can be found, suggesting more dislocations and much stronger interactions among dislocations.

The protective chromium coating was prepared on P110 steel by employing pack cementation. The corrosion behaviors of P110 steel and the obtained coating in CO₂-saturated simulated oilfield brine were studied by static complete immersion tests and electrochemical measurements. The corrosion attacks of the samples were determined by mass loss, corroded surface morphologies, corrosion products, and results of electrochemical measurements. The experimental results showed that the coating was uniform, continuous and compact. The chromium coating was slightly corroded, and the mass loss and corrosion rate of the coating were far lower than those of P110 steel. Chromium coating has higher self-corroding potential and lower corrosion current density than P110 steel in accordance with the electrochemical tests results. Taken as a whole, chromizing treatment has significantly improved the corrosion resistance of P110 steel.

The microstructure evolution of Ti-47Al-2Cr-2Nb alloy was investigated on liquid metal cooling type directional solidified apparatus at high temperature gradient. The analysis shows that it is solidified with primary β cells/dendrites, and then α phase is formed through peritectic reaction. Once the columnar grains grow into the steady state, the lamellar orientation inclined with the angle of 45° to the withdrawal direction is more favored than that with parallel to the withdrawal direction. In addition, α phase grain nucleates from β-interdendrite regions, and grows up to the dendritic trunk. If no other α grain hinders its growth, it would occupy the whole dendrite, or it would stop at the dendritic trunk for the weakened motivating drive in the β dendritic core.

Whether the active catalytic species are in a liquid, solid phase, surface premelting or surface processes during CNT or other nanowire growth are controversial. In order to explore the mechanism for catalytically grown carbon nanotube (CNT), the mechanism for CNT grown under different temperatures was proposed tentatively. With ethanol chemical vapor deposition (CVD), carbon n.anotubes (CNTs) were synthesized controllably on Si substrates using cobalt (Co) as a catalyst. The effects of the Co particle size, growth temperature and ethanol pressure on CNT growth were investigated. A different dependence of CNT growth on the Co particle size at different ranges of the growth temperature was found.

The Ce (x nm)/Au (15 nm) stacked layers were used as semitransparent cathodes in the top-emission organic light emitting devices (TOLEDs) fabricated on a p-type silicon anodes and substrate, where x varies from 4 to 16. The consequence of the Ce layer thickness on transmittance and the device performance were studied when the organic layers NPB (60 nm)/ALQ (60 nm) were kept unchanged, where NPB was N, N′-bis-(1-naphthl)-diphenyl-1, 1′-biphenyl-4, 4′-diamine, and AlQ is tris-(8-hydroxyquinoline) aluminum. The cathode of Ce (11 nm)/Au (15 nm) has a transparency of 46%, and the TOLED with it achieves the highest luminescence efficiencies: a current efficiency of 0.91 cd/A at 13.7 V and a peak power efficiency of 0.28 lm/W at 9 V. The turn-on voltage is 3.0 V. The Ce/Au cathode is both chemically and electrically stable.

The layered LiNi_0.6Co_0.2−xMn_0.2Mg _xO₂ (x=0.00, 0.03, 0.05, 0.07) cathode materials were prepared by a co-precipitation method. The properties of the Mg-doped LiNi_0.6Co_0.2Mn_0.2O₂ were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements. XRD studies showed that the Mg-doped LiNi_0.6Co_0.2Mn_0.2O₂ had the same layered structure as the undoped LiNi_0.6Co_0.2Mn_0.2O₂. The SEM images exhibited that the particle size of Mg-doped LiNi_0.6Co_0.2Mn_0.2O₂ was finer than that of the undoped LiNi_0.6Co_0.2 Mn_0.2O₂ and that the smallest particle size is only about 1 μm. The Mg-doped LiNi_0.6Co_0.2Mn_0.2O₂ samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram (CV), and electrochemical impedance spectra(EIS). The optimal doping content of Mg was that x= 0.03 in the LiNi_0.6Co_0.2−xMn_0.2Mg _xO₂ samples to achieve high discharge capacity and good cyclic stability. The electrode reaction reversibility and electronic conductivity was enhanced, and the charge transfer resistance was decreased through Mg-doping. The improved electrochemical performances of the Mg-doped LiNi_0.6Co_0.2Mn_0.2O₂ cathode materials are attributed to the addition of Mg²⁺ ion by stabilizing the layer structure.

The conductive nano-sized zinc particles were embedded in an insulating amorphous silica matrix, and the hybrid films were obtained by a sol-gel method. The stable hybrid sol solution was prepared by hydrolysis and condensation of Methyltrimethoxysilane (MTMS) with a one-step acidic catalyst process. Hybrid films were dip-coated on silicon wafer and cured at 120 °C for 60 minutes. The structural characterization of hybrid films were investigated by means of attenuated total reflection infrared (ATR-IR) spectroscopy and X-ray diffraction (XRD). The electrical properties of the films were examined with four-point probe. Hybrid films showed to be relatively dense, uniform and defect free. The conductivity of hybrid films was varied with the different contents of zinc nanoparticles and the thickness of the film. It was observed that there was the percolation threshold for the film’s electrical properties.

The photocatalytic degradation of E.coli membrane cell by ZnO nanowires was studied using field-emission scanning electron microscope(FE-SEM), fluorescence microscopy, and Attenuated total reflection fourier transform infrared(ATR-FTIR). The outer membrane of E.coli was removed completely in the presence of ZnO nanowires under UV irradiation, and the cells became twisted shapes without a mechanically strong network. After ZnO nanowires photocatalysis, the permeability of the treated cells increased to some degree that could be confirmed by quantum dots labeling technique. Structural changes in the cell wall membrane were revealed by the decay of the characteristic groups bands in ATR-FTIR spectra.

Four kinds of pure silicate ceramic particles, CaSiO₃, Ca₃SiO₅, bredigite and akermanite were prepared and their bactericidal effects were systematically investigated. The phase compositions of these silicate ceramics were characterized by XRD. The ionic concentration measurement revealed that the Calcium (Ca) ion concentration were relatively higher in Ca₃SiO₅ and bredigite, and much lower in CaSiO₃ and akermanite. Accordingly, the pH values of the four silicate ceramics extracts showed a positive correlation with the particle concentrations. Meanwhile, by decreasing the particle size, higher Ca ion concentrations can be achieved, leading to the increase of aqueous pH value as well. In summary, all of the four silicate ceramics tested in our study showed antibacterial effect in a dose-dependent manner. Generally, the order of their antibacterial activity against E.coli from strong to weak is Ca₃SiO₅, bredigite, CaSiO₃ and akermanite.

Titanium rods were processed into implant samples with cavity and groove in which was filled with HAP/β-TCP porous osteoconduction composite materials in order to increase the mechanical stability of the implant in vivo. The phase compositions of the composite was characterized by X-ray diffraction (XRD) and scanning electron microscopy(SEM). Histological evaluation showed that the biogradable composite could enhanced the ability of new bone formation. The composite can conduct new bone tissue growing into the cavities gradually after implanted into animal, and then achieve mechanical fixation. The filling biogradable compound exhibited excellent biocompatibility, which combined with the new bone tissues tightly without inflammation and loosing.

In order to reduce the amount of volumetric shrinkage that occurs in dental composites as a result of curing, a new kind of dental matrix resin combining bisphenol-S-bis(3-meth acry late-2-hydroxy propyl)ether(BisS-GMA) with the expanding monomer unsaturated spiro orthoesters 2-methylene-1, 4, 6-trispiro[4, 4] nonane (SOE) was prepared, with triethylene glycol dimethacrylate (TEGDMA) as diluent. CQ (camphorquinone) of 1wt% and DMAEMA (2-(dimethylamino) ethyl meth acrylate) of 2wt% were used as photoinitiation system to initiate the copolymerization of the matrix resins. The performance including volumetric shrinkage, degree of conversion and condition of the ring-opening reaction of SOE, as well as curing time and the tensile bond strength were investigated respectively by the dilatometer, Fourier transfer infrared, the universal testing machine, and so on. The ring-opening polymerization of SOE occurred. Meanwhile, the obtain copolymers were crosslinked. The matrix resin containing BisS-GMA and SOE showed a reduced amount of volumetric shrinkage at 1.52%, which is a promising strategy for obtaining a polymer with a low amount of volumetric shrinkage. Furthermore, the other properties were not compromised.

Bioabsorbable chitosan/β-glycerol phosphate (CS/β-GP) composite membranes were fabricated through a relatively PH neutral and mild sol-gel process for guided bone regeneration (GBR). Their structural properties, morphology, and tensile strength were investigated. FTIR and XRD analyses indicated that there were chemical bonds between the CS andβ-GP. SEM analysis revealed that the CS/β-GP composite membranes had a porous structure both at the surface and in sublayers. Even though the incorporation ofβ-GP in the CS matrix decreased the initial tensile strength of the membrane, the CS/β-GP membranes were still fit for GBR application with their tensile strength of roughly 1 MPa. The concentration ofβ-GP was proportional to the pore size and thickness but was inversely proportional to the tensile strength of the CS/β-GP membrane. The present findings indicate that, based on its characteristics, the CS/β-GP composite membrane is a potential bioresorbable membrane for use in guided bone regeneration.

The influence of platform-switched abutment on stress distribution within the surrounding bone, fixture, abutment, and screw under various loading conditions were studied. Two 3-D finite element models representative of an implant-supported metal crown for the mandibular first molar and its surrounding bone were computed. Model A simulated the implant with non-platform-switched abutment and model B was for platform-switched abutment. A load of 100 N was applied vertically and obliquely at the center fossa, the tip of the buccal cusp and the distal fossa, respectively. The results show that the distribution of Von Mises stress in the two models is similar. When platform-switched abutment is used, the maximum Von Mises stress within the surrounding bone is lower; however, this value is higher within the fixture and screw.

The self-made demineralized teeth samples treated with preamble resin to seal or not were observed under electron microscopy and tested microhardness value to show surface structure and hardness of demineralized enamel.The experimental results showed that the permeable resin formed longer resin tags on the surface of the enamel and a lot of cracks in the deep part which has a higher microhardness value than ordinary enamel.

A new method for preparing expanded graphite-based composites (EGCs) was developed. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM) and nitrogen adsorption. The experimental results indicated that the EGCs was not simply mechanical mixture of EG and activated carbon, instead the activated carbon was coated on the surface of interior and external pores of the EG in the form of thin carbon layer. The thickness of the activated carbon layer was nearly one hundred nanometers by calculation. It was shown that the higher the impregnation ratio and the activation temperature were, the easier the porosity development would be. And the BET surface area and the total pore volume were as high as 1978 m²/g and 0.9917 cm³/g respectively at 350 °C with an impregnation ratio of 0.9.

CoFe₂O₄ nanoparticles (NPs) were synthesized by coprecipitation method using FeCl₃·6H₂O and CoCl₂·6H₂O as precursors. The synthesized conditions were optimized, such as added means of precipitator, quantity of precipitator, the mol ratio of Fe³⁺ to Co²⁺, reaction temperature and pH value. The synthesized material was characterized by XRD, TEM, FTIR, EDS, Raman and its magnetic properties were studied by VSM. The experimental results confirm that the sample is cubic spinel structure CoFe₂O₄ with a narrow size distribution and a good dispersion feature. CoFe₂O₄ NPs with well-controlled shape and size was obtained at 70 °C. The magnetic properties indicate superparamagnetic behavior and good saturated magnetization.

The properties of native silk fibroin (SF) solution in the gland of silkworms during the full fifth instar larval stage were examined in an attempt to elucidate the mechanism of natural silk spinning in the silkworm. The flow and gelation behavior, birefringence phenomenon, rheological properties, specific viscosity and conformation of SF solutions from the gland of silkworms were measured by polarized light microscope, HAKKE rheometer, Ubbelohde viscometer and Solid-state ¹³C NMR, respectively. After comparing their properties with regenerated SF solutions from natural silk fibers, it is believed that there exists a progressive maturation process favorable to spin silk fibers with excellent properties from native SF solution and a weak bonded and highly oriented SF gel network with SF molecules partly extended in α-helix conformation is formed in the middle section of the gland of silkworms. This suggests that a biomimetic maturation process for making spinnable solution might be necessary for artificial silk fiber spinning in order to obtain improved fiber properties.

Nano-structured cubic SnO₂ crystalines were successfully synthesized through solvothermal route. The obtained products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution TEM (HRTEM). The study showed that, the SnO₂ particles were rutile structured and almost uniformly cube shaped crystals in quantum size (3–8 nm). Self-assembly behavior of the cubic SnO₂ quantum dots was also observed. The synthesis process can be defined as an nonhydrolysis (NH) hydroxylation reaction provided by the amide elimination of carboxylated precursors. The formation of cubic morphology of SnO₂ can be ascribed to the mild reaction featured by high nucleation rate and low growth rate, surface energy difference of the crystallographic facets of SnO₂ and the passivation effect of the starting material-dodecylamine which drastically reduced the dipole interation. The selfassembly of the cubic SnO₂ quantum dots was driven by van der Waals force and capillary force.

The effect of unbalanced coefficient of magnetron (UCM) on the structure and tribological properties of CrN _x hard coatings was studied. The CrN _x coatings were deposited on both Si wafer and hardened tool steel substrates using a closed-field unbalanced magnetron sputtering ion plating technique in a gas mixture of Ar+N₂ under different unbalanced magnetron conditions. The coatings were characterized by means of XRD, XPS, SEM, microhardness tester and pin-on-disc tribometer to study respectively their structure, chemical bonding state, microstructure, hardness and tribological properties. The experimental results show that the UCM has a profound effect on the structure, hardness and tribological properties of the CrN_x coatings. With increasing the values of UCM, the dominant phases in the deposited coatings evolved from Cr+Cr₂N to Cr₂N+CrN, the microstructure became denser and the hardness increased; in addition, reduced coefficient of friction and improved wear resistance of CrN _x coatings were also observed under a larger UCM.

The effects of microwave sintering and conventional H₂ sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying & calcining-continuous reduction technology were investigated. In comparison to the conventional H₂ sintering processing, microwave sintering to W-15Cu can be achieved at lower sintering temperature and shorter sintering time. Furthermore, higher performances in microwave sintered compacts were obtained, but high microwave sintering temperature or long microwave sintering time could result in coarser microstructures.

The Al₂O₃-ZrO₂(3Y)-SiC composite ceramics used in solar thermal power were prepared by micrometric Al₂O₃, nano-ZrO₂ and SiC powders under the condition of pressureless sintering. The bulk density and bending strength of samples with 10vol% nano-ZrO₂ sintered at 1480 °C were 3.222 g/cm³ and 160.4 MPa, respectively. The bending strength of samples after 7 times thermal shock tests (quenching from 1000 °C to 25 °C in air medium) is 132.0 MPa, loss rate of bending strength is only 17%. The effect of nano-ZrO₂ content on the microstructure and performance of Al₂O₃-ZrO₂(3Y)-SiC composite ceramic was investigated. The experimental results show that the bending strength of samples with above 10vol% nano-ZrO₂ content has decreased, because the volume expansion resulting from t-ZrO₂ to m-ZrO₂ phase transformation is excessive; Adding proper nano-ZrO₂ would be contributed to improve the thermal shock resistance of the composite ceramics. The Al₂O₃-ZrO₂(3Y)-SiC composite ceramic has promising potential application in solar thermal power.

Composite powders of nanocrystalline WC-10Co (15wt%), Y₂O₃ (8mol%) stabilized nanocrystalline ZrO₂ (30wt%), industrial cobalt powder (4.5wt%) and submicron Al₂O₃ (55wt%) composite powders were fabricated by high-energy ball-milling process. The nanocomposite powders were consolidated by microwave sintering process at temperature ranged 1300 °C–1550 °C for 15 min, respectively. The optimum consolidation conditions, such as temperature, were researched during microwave sintering process. Vickers Hardness of the consolidated cermets was measured by using a Vickers indentation test, and density of specimens was also determined by Archimedes’ principle. Microwave sintering process could not only increase the density of Al₂O₃-ZrO₂-WC-Co cermets and reduce the porosity, but also inhibit abnormal grain growth.

The effects of die structure such as the height of the welding, the welding angle and chamber the shape of the bridge on the welding quality of profiles were investigated by means of the commercial software DEFORM-3D. The numerical simulation results show that the welding quality of the hollow profiles has great sensitive to the die structure. With increasing the welding chamber height and decreasing the welding angle of the die leg can improve the welding quality. In addition, the welding quality index k of the new designed shape of the die leg is little down from 4.1 to 3.9 comparing the standard leg.

A bending creep setup was introduced and its feasibility to evaluate creep behavior of materials was experimentally verified on pure Sn. Thereby, the creep of eutectic Sn-9Zn was studied. It was identified that high and low stress regimes exist in the creep of Sn-9Zn, and in both stress regimes, the data obtained well fit the modified equation of Norton power law. Parameters n and Q in the modified Norton equation obtained are very closed to those reported by other researchers by means of conventional tensile creep tests. The mechanisms governing the creep deformation of Sn-9Zn in both stress regimes were also discussed.

SnO₂ hollow microspheres were fabricated via a hydrothermal synthesis method assisting by the complex surfactant system of polyacrylamide and polyethylene glycol. Observation by field emission scanning electron microscopy (FESEM) showed the SnO₂ hollow spheres were composed of nanoparticles. The growth mechanism for the formation of hollow spheres was proposed. UV spectroscopy and photoluminescence (PL) were used to investigate the optical properties of the products. The PL result showed that four peaks, containing the emission from recombination of free excitons, were observed in the photoluminescence spectrum.

A three levels orthogonal table- L₉(3⁴) was used, namely, impact angle, rotating speed, erodent size, and surface configuration were considered. The three bionic surface configurations are pit, groove, and ring. The experimental results indicate the experiment factors affecting erosive rate are, in their sequence of contribution, erodent size, impact angle, configuration, and rotating speed; the erosive rate increased with increase in rotating speed, erodent size; the erosion resistance of the sample with ring structure is higher than that of the other two samples. Based on this result, regression orthogonal experiment was carried out to select the optimal erosion resistance condition with respect to the ring bionic surface configuration. Regression equations between erosive rate and experimental factors of ring surface configurations were obtained.

Compounds Sr₄Eu₂Ti₄Nb₆O₃₀ and Sr₅EuTi₃Nb₇O₃₀ with filled tetragonal tungsten bronze structure were prepared, and the dielectric characteristics and ferroelectric transition were investigated. Both ceramics displayed weak frequency dependence in room temperature dielectric constant, which decreased from 125 to 118 for Sr₄Eu₂Ti₄Nb₆O₃₀, from 206 to 195 for Sr₅EuTi₃Nb₇O₃₀ in the frequency range of 10 kHz to 1 MHz. The present ceramics showed a diffuse ferroelectric phase transition. The frequency independent transition temperature (T _m) indicated the above compounds had no relaxor property. The diffuseness (γ) was 1.45 and 1.64 for Sr₄Eu₂Ti₄Nb₆O₃₀ and Sr₅EuTi₃Nb₇O₃₀ respectively. The weak ferroelectric of the present materials are indicated from the P-E hysteresis loops, and a small 2P _r of 0.596 μC/cm² and 0.068 μC/cm² were observed for Sr₄Eu₂Ti₄Nb₆O₃₀ and Sr₅EuTi₃Nb₇O₃₀ respectively.

Various parameters in spark plasma sintering(SPS), such as sintering temperature, holding time, heating rate, and pressure, were adopted to investigate their effects on the densification of pure SnO₂ power. The obtained experimental data show that the SPS process enhances densification. The high-density undoped SnO₂ ceramics (96.6% of theoretical) was obtained at much lower temperature (1000 °C), within a much shorter time, compared to the conventional sintering process. The high-density undoped SnO₂ ceramics (96.6% of theoretical) were obtained by SPS, under the condition of temperature:1000 °C, pressure: 40 MPa, heating-rate: 200 °C/min, and holding time: 3 min

High resolution solid-state ²⁹Si MAS NMR, combined with XRD, SEM and FTIR were used to characterize the pozzolanic activity of FA, type of main pozzolanic reaction products, and the effect of pozzolanic reaction on the C-S-H microstructure in fly ash-cement (FC) paste. The experimental results indicate that in the hydrated FC paste with 30% dosage of FA at 3 d, FA partially participated in the pozzolanic reaction, while, at 120 d, FA largely reacts. During the hydration of FC paste at laboratory temperature, the pozzolanic reaction products are C-S-H gel rather than zeolitic gel. Moreover, after the covalent bonds of Si-O-Si, Si-O-Al and Al-O-Al in the structure of FA are broken, monosilicates Si-OH and Al-OH groups form, these chemical species can connect C-S-H dimers, thus producing more Al-free C-S-H and aluminous C-S-H than in the plain cement paste. The increased content of Al for Si substitution in the bridging tetrahedra of C-S-H may decrease the stability of C-S-H, which results in a rather obvious loss in the mechanical strength of hardened FC paste.

To meet the requirements of construction of concretes filled in the steel tube arches, a C60 grade micro-expansive self-compacting concrete (SCC) was prepared from manufactured sand (MS). The utilization of MS with a high content of quarry limestone fines was dealed for SCC applications. The workability, compressive and splitting strength, modulus of elasticity, restrained expansion and chloride ion permeability as well as freeze-thaw resistance of three MS-SCC mixes with fines content of 3%, 7% and 10% were tested and compared with those of the natural sand (NS)-SCC mix. The experimental results indicate that the performances of the C60 MS-SCC with fines content of 7% are excellent and compared favorably with those of C60 NS-SCC.

The influence of coarse aggregate content on concrete properties was investigated. From the perspective of Frame Concrete Theory, six groups concrete were produced with the same proportion except for coarse aggregate content, with coarse aggregate content of 0%, 40%, 50%, 60%, 75%, and 80%, respectively. Slump, compressive and flexural tensile strengths, elastic modulus, and water penetration were tested to research the effect of coarse aggregate content on concrete. The experimental results reveal that slump reduces with increasing of coarse aggregate content, while compressive strength, elastic modulus and flexural tensile strength increase with the coarse aggregate content increasing, and water penetration reduces with coarse aggregate content increasing before 75% then increased. Workability, strength, durability and economical indexes system were established to optimize the coarse aggregate content in concrete based on efficacy coefficient method. The optimization results show that when coarse aggregate content is 60%, the system efficacy coefficient reaches to 0.89, and it expresses the better comprehensive performance.

To use many asbestos tailings collected in Ya-Lu highway, and to explore the feasibility of using asbestos tailings as aggregates in common asphalt mixtures, and properties of some asphalt mixtures were evaluated as well. X-ray diffraction (XRD), X-ray fluorescent (XRF), and atomic absorption spectrophotometry (AAS) were employed to determine the solid waste content of copper, zinc, lead, and cadmium. Volume properties and pavement performances of AC-25 asphalt mixture with asbestos tailings were also evaluated compared with those with basalt as aggregates. XRD and XRF measurement results infer that asbestos tailing is an excellent road material. Volume properties of AC-25 asphalt mixture with asbestos tailings satisfied the related specifications. No heavy metals and toxic pollution were detected in AAS test and the value of pH test is 8.23, which is help to the adhesion with asphalt in the asphalt concrete. When compared with basalt, high temperature property and the resistance to low temperature cracking of AC-25 asphalt mixture was improved by using asbestos tailings as aggregates. In-service AC-25 asphalt pavement with asbestos tailings also presented excellent performance and British Pendulum Number (BPN) coefficient of surface.

The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites(CFGCC) with carbon fiber content(1% by the weight of cement), graphite powder contents (0%–50% by the weight of cement) and CCCW(cementitious capillary crystalline waterproofing materials, 4% by the weight of cement) were studied. The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena. The percolation threshold was about 20%. A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers, 20wt% or 30wt% of graphite powders under uniaxial compressive tests, indicating that this type of smart composites was a promising candidate for strain sensing. The measured gage factor (defined as the fractional change in resistance per unit strain) of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22, respectively. With the addition of CCCW, the mechanical properties of CFGCC were improved, which benefited CFGCC piezoresistivity of stability.

The hydration behaviors and expansive properties of MgO-type expansive agent curing at different temperatures and environment were investigated. When the curing temperatures changed from 25 °C to 50 °C, the conductivities of MgO samples increased from 40 to 80 μs/cm, and the hydrations of MgO were quickened up obviously. Through SEM observation, the hydration product of MgO cured at 50 °C for 28 day was about 2–3 μm in length. The expansion of pastes with 5% of the MgO-type expansive agent was from 0.36% to 1.01% when the curing temperature changed from 25°C to 50 °C. When 8% of the MgO-type expansive agent was added, the early shrinkage of concrete was reduced. The expansion ratio increased with the curing temperature, and the expansive cracking of concrete with MgO-type expansive agent might be decreased by blending fly ash.

The properties of concrete incorporating circulating fluidized bed combustion (CFBC) bed ash and ground granulates blast-furnace slag (GGBS) were studied. Compressive strength, drying shrinkage, mercury intrusion porosimetry (MIP), scanning electronic microscopy (SEM), and X-ray diffraction (XRD) of concrete samples containing CFBC bed ash and GGBS were used. This work used initial surface absorption test (ISAT) and rapid chloride penetration test (RCPT) on concrete to measure the absorption and the ability of concrete to resist chloride ion characteristics for different concrete samples containing CFBC bed ash and GGBS. Open circuit potential (OCP), direct current polarization resistance were obtained to evaluate rebar corrosion. The CFBC bed ash was X-ray amorphous and consist of SiO₂, Al₂O₃ and CaO compounds. As the replacement of CFBC for sand increases, the rate of initial surface absorption (ISA) increases but compressive strength decreases. When the content of CFBC bed ash replacement for sand maintains constant, the replacement of GGBS for cement increases, compressive strength increases but the rate of ISA decreases. Chloride and corrosion resistance of rebar significantly improve by utilizing a proper amount of CFBC bed ash and GGBS in concrete.

The antifreeze critical strength and the pre-curing time of low-temperature concrete were studied by means of guaranteed rate of compressive strength and antifreeze performance for the structural safety requirement of concrete engineering, suffering once freeze damage under air environment. It is shown that the antifreeze critical strength is 3.7–4.4 MPa, pre-curing time is 18–32 h by guaranteed rate of compressive strength, and the antifreeze critical strength is 3.7–4.4 MPa, pre-curing time is 18–32 h by guaranteed rate of antifreeze performance. It can be found that the method of guaranteed rate of compressive strength is sensitive to the defect which generated by freeze damage in the concrete interior. The method is fit to evaluate the antifreeze critical strength of low-temperature concrete.

This study was conducted to evaluate the sensitivity of compressive strength, water permeability and electrical resistance of near-surface layer concrete with different fly ash contents to curing conditions. It is shown that the sensitivity to curing condition and fly ash content descends in the following order: difference between internal and surface resistivity (ρ) at 28 days, water permeability and compressive strength; both of longer duration of moist curing and use of fly ash in concrete enhanced the water penetration resistance. It is indicated that the resistivity difference ρ at 28 days can reflect accurately the curing history of fly ash concrete regardless of mix proportions; and use of fly ash in concrete requires longer moist curing duration.

The electrodeposition method for rehabilitation of the cracked reinforced concrete, based on the electrochemical technique, was presented here. The aim of this study was to evaluate the influence of additive on the formation of electrodeposits in the concrete cracks. Cracked mortar specimens of size 40 mm×40 mm×160 mm were immersed in electrolyte solutions(ZnSO₄, MgSO₄), and a constant current was applied between the reinforced steel and the external electrode for 15 days. Rate of surface coating, rate of crack closure and rate of crack filling depth were measured and the appearance of electrodeposits in the cracks was observed. The experimental results demonstrate that, under the experimental conditions, rate of surface coating and crack filling depth increase, while rate of crack closure decreases as the percengtage of additive increases. In addition, the electrodeposits become more denser and the microstructure varies with additive content, while the compositions of electrodeposits do not change.

The freeze-extraction and freeze-gelation methods were used to prepare highly porous β-TCP/CS scaffolds with different β-TCP/CS ratio. In these methods, the suspending mixture of β-TCP and chitosan was frozen, the frozen mixture was immersed in a non-solvent(0.05 mol/L NaOH/ehanol aqueous) bath to allow the exchange between solvent(acetic-acid aqueous) and non-solvent at a temperature lower than the freezing point of the acetic-acid. Then, the β-TCP/CS scaffolds were formed and dried at room temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), gas chromatography (GC) and omnipotence material testing machine were employed to characterize the β-TCP/CS scaffolds. The results of GC show that the freeze extraction of the β-TCP/chitosan scaffolds was completed when the extraction time is above 24 h. The SEM results show that the β-TCP/CS scaffolds are composed of interconnected pore network. The porosity of the β-TCP/CS scaffolds decrease with the increase of the content of the β-TCP. The β-TCP/CS scaffolds have a highest compressive strength when the chitosan/β-TCP ratio is 30:70. The present work displays that the β-TCP/CS composite scaffolds with appropriate mechanical properties and high porosity can be successfully prepared by the freeze-extraction and freeze-gelation methods.