According to the requirement of the knowledge of material mechanical properties in structure design procedure, the paper considered experimentally obtained data regarding the high-strength low-alloy A 709 Gr50 steel. In that way, ultimate tensile strength and 0.2 offset yield strength at both lowered and elevated temperatures were presented and analyzed. The effect of temperature exerted on both of the mentioned strengths was presented. Creep responses for selected temperatures and selected stress levels were also considered. All of the tests are related to the uniaxial tensile tests and were performed in the laboratory of the Department for Engineering Mechanics at the Faculty of Engineering Rijeka.

A computational model for nanotoxicology was developed based on the model proposed by International Commission on Radiological Protection. Herein, the fate and transport of inhaled nanoparticles in human respiratory tract were investigated by employing the compartmental model. The uncertainty analysis using Latin hypercube technique was performed to address the uncertainty level of the required parameters in modeling. This methodology could be employed in assessing the heath risks associated with general public or occupational exposure.

The effects of activated sintering technology of H₂ atmosphere 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. The experimental results showed that W-15Cu alloy, consolidated by activated sintering technology of H₂ atmosphere sintering for 1 h at 1300 °C, with 98.5 % relative density, transverse rupture strength 1218 MPa, Vickers hardness HV0.5 378, average grain size about 1.2 μm and thermal conductivity 192 W/m·K, was obtained. In comparison to the normal sintering process, activated sintering process to W-15Cu alloy could be achieved at lower sintering temperature. Furthermore, better properties in activated sintered compacts were obtained, and activated sintering process resulted in finer microstructure and excellent properties.

Using X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area measurement, ultraviolet-visible diffuse reflection spectra, and photoluminescence spectroscopy, the effect of mechanical milling on the photocatalytic activity of g-C₃N₄ photocatalyst was investigated. The rhodamine B, as a photodegrading goal, was used to evaluate the photocatalytic activity of g-C₃N₄. The experimental results indicate that the milling treatment is an effective method to improve the photocatalytic activity of g-C₃N₄. The enhanced photocatalytic activity was attributed to the improvement in catalyst’s surface area and dye adsorption on catalyst surface. Moreover, checking the luminescence properties of g-C₃N₄, it is found that the photocatalytic active sites on g-C₃N₄ are likely the same as luminescence sites.

ZrW₂O₈ was prepared by adjusting Zr:W mole ratio and HCl concentration in hydrothermal reaction processes. The obtained sample was crystallized in α-ZrW₂O₈ phase (cubic, P2₁3), with band gap energy of 4.0 eV. The properties of photocatalytic water splitting were examined under UV light irradiation. The average rate of H₂ evolution over 0.3wt% Pt/ZrW₂O₈ in the presence of CH₃OH as electron donor (ED) was 23.4 μmol/h, while the average rate of O₂ evolution over ZrW₂O₈ in the presence of AgNO₃ as electron scavenger (ES) was 9.8 μ mol/h. Moreover, H₂ was evolved over 0.3wt% Pt/ZrW₂O₈ from pure water splitting at a rate of 5.2 μ mol/h. The study indicated that the band structure of ZrW₂O₈ was suitable for reducing H⁺ to H₂ and oxidizing H₂O to O₂. The band structure and photocatalytic water splitting properties of ZrW₂O₈, different from either ZrO₂ (5.0 eV) or WO₃ (2.7 eV), were attributed to the hybridization of W5d and Zr4d in conduction band (CB) as well as the change in crystal structure.

About 300 μm thickness uniform thermal barrier coatings (TBCs) were deposited on the 1Cr18Ni9Ti samples by solution precursor plasma spray (SPPS). The analysis methods, such as TEM, SEM, and XRD were used to characterize the coatings in the aspects of microstructure and phase compositions. The samples were quenched from 1121 °C to room temperature by forced-air to measure the thermal cycling capability. Coatings density were measured by means of water displacement. The experimental results show that grain size of the SPPS TBCs is about 30 nm with desired tetragonal phase ZrO₂, and the SPPS TBCs(with 16% porosity) consist of arcuate pores, gelatin and melted particles. The hardness of the coatings is HR45Y38.5 and bond strength between coatings and substrates is 24.2 MPa. The thermal shock test show the coatings have a average life of 500 cycles which is about 2.5 times than that of conventional air plasma spray (APS) TBCs.

Monodispersed spheroidal SnO₂ nanocrystals with the grain size of 8–30 nm were synthesized by the precipitation method using SnCl₄·5H₂O (stannic chloride hydrate) as raw materials. Differential scanning calorimetry/thermogravimetry (DSC/TG), X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize the structure of SnO₂ nanocrystals. The influences of the calcination temperature and time on the lattice constant, the lattice distortion and the grain size of SnO₂ nanocrystals were discussed based on the XRD results. The grain growth kinetics of SnO₂ nanocrystals during calcination process was simulated with a conventional grain growth model which only took into account of diffusion and with a new isothermal model proposed by our group, which took into account of both diffusion and surface reactions. Using conventional model, the grain growth rate constant of SnO₂ crystals is 1.55×10⁴ nm⁵/min with a pre-exponential factor of 5 and an activation energy of 108.62 kJ/mol. Compared with the convention model, the new isothermal model is more realistic in reflecting the grain growth behavior of SnO₂ nanocrystals during the calcination process. This indicates that the grain growth of SnO₂ nanocrystals is controlled by both diffusion and reaction factors, and the effect of surface reactivity on the grain growth of SnO₂ nanocrystals could not be ignored. A combined activation energy estimated with the new isothermal model is 53.46 kJ/mol.

Copper nitride (Cu₃N) thin films were successfully deposited on glass substrates by reactive radio frequency magnetron sputtering. The effects of sputtering parameters on the structure and properties of the films were studied. The experimental results show that with increasing of RF power and nitrogen partial pressure, the preferential crystalline orientation of Cu₃N film is changed from (111) to (100). With increasing of substrate temperature from 70 °C to 200 °C, the film phase is changed from Cu₃N phase to Cu. With increasing sputtering power from 80 W to 120 W, the optical energy decreases from 1.85 eV to 1.41 eV while the electrical resistivity increases from 1.45 ×10² Ω · cm to 2.99 × 10³ Ω · cm, respectively.

A new bacterial strain, was designated as strain Acidiphilium cryptum DX1-1, accumulates intracellular poly-β-hydroxybutyrate particles, four methods which have advantages and disadvantages for each were employed to extract PHB. Chloroform-sodium hypochlorite method is the best in extracting PHB form Acidiphilium cryptum DX1-1. The extraction rate reaches 73%, the purification rate is 92% and molecular weight is 326 kg/mol. Then the PHB extracted by this method was analyzed by ultraviolet-visible absorption spectroscopy, fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR). The results show that PHB from strain DX1-1 has the same biochemical structure and character with PHB standard. Mass spectrometer (MS) analysis reveals that the long chain of PHB is destroyed when treated by chloroform-sodium hypochlorite. The differential scanning calorimetry (DSC) of PHB shows PHB from Acidiphilium cryptum DX1-1 has low degree of crystallinity which makes the PHB has a wider range of applications.

Based on diffusion of nerve growth factor (NGF) from degradable material, a novel nerve guidance conduit (NGC) with sustained NGF release was prepared by embedding NGF into a degradable RGD-modified composite which has good cell affinity and biocompatibility. In vitro, the NGF release was quantified using enzyme-linked immunosorbent assay method, and the bioactivity of released NGF was examined by PC-12 cell bioassay. In vivo, the performance of the NGF-containing conduit was examined using rat sciatic nerve defect model. The experimental results show that the NGF release process is prolonged over 30 days, and at least some degree of NGF bioactivity is preserved after the fabrication process. Due to the promoting effect of bioactive released NGF on nerve regeneration, the performance of NGC for nerve repair is improved significantly. The results of this study indicate that the sustained NGF release system is suitable for peripheral nerve repair.

Physical-chemical characteristics of the band sawing dusts regarding to recovery of pure silicon from them were investigated. The experimental results show 50vol%–60vol% amorphous phases exist in the dusts, which is mostly amorphous silica. The as-received saw dusts are found to form hard agglomerates of larger than 50 microns in diameter. The iron-based inclusions collected by magnets are found to match well with the band saw material in XRD patterns. Weight loss in heating was observed by thermal gravity tests, up to 900 °C, presumably due to reaction of the amorphous silica with carbon contaminant in the dusts. The saw dusts were variously treated to examine their physical-chemical responses, and the results were also presented.

CBN-AlN composite abrasive grits and AISI 1045 steel were brazed using Ag-Cu-Ti active filler alloy by heating up to the temperature of 890, 900 and 920 °C, respectively, and then held at the temperature for 8 min. Optical microscope, scanning electron microscope and X-ray diffraction equipment were utilized to study the effects of heating temperature on the microstructure of the joining interface. The compressive strength of the brazed composite grits was also measured. The experimental results show that the atoms of Ti, Al, B and N have preferentially penetrated towards the joining interface of composite grits and filler alloy. The compounds of Ti-nitride, Ti-borides and Ti₃AlN were formed in the reaction layer. Degradation effect was not made on the compressive strength of the CBN-AlN composite grits when the brazing process was carried out in the temperature range of 890–920 °C.

C/SiC composites prepared by chemical vapor infiltration (CVI) were subjected to a stationary loading of 160 MPa in a combustion gas environment with flame temperature of 1300 °C. Lifetime of C/SiC composites in such environment was measured. Microstructures of the composites after the testing were also characterized by SEM. The experimental results indicate the lifetime of C/SiC composites is average 2.3 hours in combustion gas environments. The combustion gas flow accelerates the damage of carbon fibers and the failure of the composites by speeding up the diffusion of gas reactants and products, destroying the layer of SiO₂ on the surface of SiC coating and bringing fused SiO₂ inside the composites. The fracture face of C/SiC is uneven, i e, a flat area close to the windward side and a pulling-out of long fibers near the leeward side, which results from the directionality effect of the combustion gas flow.

In order to study the influence of temperature on compressive strength of polymer grouting material, the compression specimen injection mold is self-made, and the uniaxial compressive test was carried out in the temperature control box under different temperatures. The change regularity of compressive strength of polymer grouting material under different temperatures and the law of volume changes of polymer samples were obtained. The experimental results show that: the compressive strength of polymer material increases with the increase of density; the temperature change has a certain influence on the compressive strength of polymer grouting material; the compressive strength decreases with temperature increases under the same density, but the compressive strength is not significantly affected by temperature when the density is less than 0.4 g/cm³; the volume change of the samples accords with the law of thermal expansion and contraction when temperature changes, and the increase of the volume is obvious when it is under high temperature. The achievements will provide an important basis to the application of the polymer grouting material.

The radiation effect of neutrons in a reactor on polyurethane was studied. The gases produced by irradiated samples were analyzed by gas chromatography, and the dynamic mechanical and compression properties of the samples were also studied. The positron annihilation lifetime of irradiated samples was measured at room temperature in vacuum. The experimental results indicate that gas chromatography is a powerful tool to quantitatively analyze the gas products from neutron-irradiated polyurethane and characterizes the chemical changes in the sample. And the changes in microstructure determined from the PAL correlate well with the measurements of the mechanical properties by dynamic mechanical analysis (DMA).

Zwitterionic phosphobetaine bearing a hydroxyl and a zwitterionic group, 8-hydroxy-2-octyl phosphorylcholine (HOPC), was synthesized and constructed to the surface of silk fibroin(SF) films in order to improve the hemocompatibility of fibroin films by a an isocyanate head group. The surface characteristics of the modified films were measured by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and electron spectroscopy for chemical analysis (ESCA), displaying the successful immobilization of Zwitterionic phosphobetaine on the surface of these fibroin films. Moreover, the further platelet adhesion test in platelets rich plasma (PRP) of human beings showed the zwitterionic phosphobetaine led mainly to good nonthrombogenicity. The experimental results indicated a reasonable approach to improve the blood compatibility of fibroin films.

Gelatin microsphere (GMS) was prepared through W/O emulsion chemicalcrossline method. The best formula was selected by examining its appearance, size, drug carrier and drug dissolution rate. The experimental results showed that the optimized gelatin microspheres were spherical ball with smooth surface and had well dispersion. The average size of blank gelatin microspheres was 15.84 μm, while the loaded microspheres’average diameter were 33.10 μm. It was also shown that drug loading of microspheres increased with increasing loading capacity, but drug encapsulation efficiency had a trend of climbing up and then decline. The encapsulation efficiency reached the maximum when the dosage ratio was 2:1. And the results show ceftiofur sodium microspheres have sustained release in the PBS buffer of pH7.4.

Two kinds of azo polysemicarbazides were prepared based on 3, 3′-azobis (benzoylhydrazide) (ABH) and two kinds of diisocyanates via solution polymerization. The structures were characterized by Fourier-transform infrared (FT-IR) technique and elemental analysis. Inherent viscosities of the polymers were 0.32 and 0.29 dL/g and both could be dissolved in H₂SO₄ and polar organic solvents. Thermal gravimetric analysis (TGA) presented a multi-step degradation and a decomposition temperature range of 230–280 °C. And photoisomerization of the azo polymers in solvent of N, N-dimethyl acetamide (DMAc) was confirmed by Ultraviolet-visible spectroscopy (UV-Vis), suggested the isomerization appearing under the ultraviolet irradiation at 365 nm and recovering completely by visible light irradiation or kept in the dark. Transmission electron microscopy (TEM) of polysemicarbazides before and after soaking in bovine serum albumin (BSA) solution confirmed the biocompatibility of azo polymers.

Polyurethane was synthesized by the copolymerization with isocyanate and diols. The structure and properties of the copolymers were characterized by infrared spectrometer (IR), differential scanning calorimetry (DSC) and thermogravimetry (TG). The rabbit blood samples was dripped on the polyurethane, which was prepared by drying and die, and the contact angle was measured by contact angle measurement, then infiltration phenomenon was observed by electron microscopy. The results showed that the contact angle of blood samples and polyurethane was decreased with increasing time, and the platelets on the polyurethane would gradually increase and more rules. Thus the polyurethane coating had good hydrophilic property and anticoagulant activity.

The title compound (13, 27-dichloro-3, 6, 9, 17, 20, 23-hexaazatricyclo-[23.3.1.1^11,15]-triaconta-l(29), 2, 9, 11, 13, 15(30), 16, 23, 25, 27-decaene-29, 30-diol-N³, N⁶, N⁹, O²⁹, O³⁰)-bis(nitrato-O,O)-Europium(III) nitrate was prepared and characterized by elemental analysis, infrared spectra, electrospray mass spectrum and X-ray diffraction, respectively. The crystal of the complex crystallizes in the monoclinic system, space group C2/c with a=2.3737(2) nm, b=14.333(1) nm, c=19.388(2) nm, β = 91.804(1)°, M _r = 850.4, V = 6.5929(8) nm³, R= 0.0333, wR= 0.0936. At room temperature, excitation of the title complex gives rise to the characteristic luminescent emissions of the Eu³⁺ ion.

To satisfy performance and long life requirements for hot forging die, Ni60-Cr₃C₂ composite coatings were prepared on the high-speed steel W₆Mo₅Cr₄V₂ using laser cladding technology. Laser clad coatings with different ratios of Ni60:Cr₃C₂ were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX) and microhardness tester, respectively. Specific heat capacity and thermal conductivity were measured by Laser Thermal Constant Meter. Thermal expansion coefficient and elastic modulus were measured by Dynamic Mechanical Thermal Analyzer and Electro-Hydraulic Servocontrolled Testing System, respectively. The results indicated that Ni60+50wt% Cr₃C₂ composite coating had dense and homogeneous structure, as well as a metallurgical bonding with the substrate. With the increase of Cr₃C₂ content, volume of chromium-containing compounds in the composite coating increased, microhardness increased and microstructure refined. The thermal physical parameters results showed that Ni60+ 50wt% Cr₃C₂ composite coating was overall worse than W₆Mo₅Cr₄V₂, but had a higher hot yield strength to alleviate hot fatigue and surface hot wear of hot forging die during hot forging and thus improve the service life of hot forging die.

The effects of surface conditioning methods on the microtensile bond strength of Y-TZP ceramic were studied based on airborne particle abrasion and resin cements. Eight square-shaped (ϕ12 mm×5 mm high) Y-TZP ceramic were studied blocks (LAVA™, 3M ESPE, USA) and flat occlusal dentin blocks were fabricated, pre-treated(airborne abrasion with 125μm Al₂O₃ particles, tribochemical silica coating with 110 μm Al₂O₃ particles modified by silica oxide), and bonded to each other using resin cements(Panavia F 2.0, RelyX Unicem). Thereafter the trilayer specimens were cut into microbar specimens with a bonding area of approximately 1.0±0.1 mm² and then microtensile bond strength tests were performed. The Y-TZP ceramic following airborne particle abrasion with 125μm Al₂O₃ and silicoating, the surface roughness of Y-TZP and its surface silica content were confirmed to increase. Overall, the Y-TZP ceramic surface treatment with a tribochemical silica coating showed the highest microtensile bond strength of the phosphate monomerbased resin cement to Y-TZP ceramic(mean MPa= 18.11±0.27(Panavia F 2.0), 17.45±0.39(RelyX Unicem). In cases in which a silica coating was applied, there was no significant difference in the bonding strength depending on resin cements (P>0.05).

In order to utilize solid wastes, ceramic simple bricks with high performances were made from industrial solid wastes such as red mud, fly ash and poor clay shale as main raw materials in this paper. The phase compositions and microstructures were tested by XRD, SEM and EPMA. The experimental results show that the water absorption is 45.64%, the porosity is 58.91%, bulk density is 1.29 g·cm⁻³, compressive strength is 54.91 MPa, bending strength is 29.52 MPa, freeze-thaw resistance is 29.28 MPa, specific heat capacity at constant pressure is 1.31 J·g⁻¹·K⁻¹, thermal diffusivity is 5.89×10⁻³ cm²·s⁻¹, and thermal conductivity is 1.15×10⁻² W·cm⁻¹·K⁻¹. These effects of additives and preparation process to the properties and microstructures were discussed in detail. The reaction mechanism was also discussed. The results of the reaction mechanism show that there has wollastonite and feldspar generated during the process of firing while Ca gathered around the feldspar, and then Ca would displace K and generated cacoclasite.

The performance of composite ceramic armor penetrated by rod projectile was studied by both numerical simulation and experiment. The penetration and damage mechanisms of the projectile-armor after high-speed collision were also observed by high-speed photography. The experimental results showed that the ballistic performance of composite ceramic armor was highly affected by the density, hardness and toughness of bulletproof ceramic. The flow stress of the failed bulletproof ceramic is not only related to the pressure but also related to the strain rate. The phenomenological method based on Bodner-Partom ceramic model was introduced to derive the growth rate of damage. Numerical simulation results show good agreement with the experimental results.

Part of an extensive research undertaken by the Concrete and Masonry Research Group at Kingston University-London was reported to demonstrate through scientific research and full-scale site trials, that quality recycled concrete aggregates can be produced and can be used successfully in a range of concrete applications. The effects of up to 100% coarse recycled concrete aggregate (RCA) on fresh, engineering and durability related properties were established and assessed its suitability for use in a rage of sustainable applications.

Serving as recycled coarse aggregate, the pretreated rural building waste was added into the concrete hollow bricks in the varying replacement of 0, 20%, 40%, 60%, 80% and 100%. By testing its compressive strength, flexural strength, mass and strength loss after freeze-thaw cycles, the impact of the different replacement on mechanical and frost-resistance properties of concrete hollow bricks was presented through SEM analysis. The experimental results show that, with the increase in recycled coarse aggregate replacement rate, the mechanical and frost-resistance properties show a downward trend; when the replacement rate is 40%, 28 d compressive strength and flexural strength of concrete hollow brick demonstrate the good peak value which meet the requirement of the national standard for ordinary small concrete hollow bricks; the interfacial structures of the pretreated recycled concrete is more complicated than those of concrete made of natural aggregate, but the former enjoys better interface bonding and tight structure.

A test for crumb rubber modified asphalt containing 20% crumb rubber particles (30 mesh) was performed using a scanning electron microscope (SEM). The experimental results indicate that the crumb rubber particles are evenly distributed in the asphalt. Shear rate sweep and shear-temperature sweep tests on the crumb rubber modified asphalt at −20–80 °C using a dynamic shear rheology (DSR) instrument, were carried out. The tests show that the complex modulus decreases with increasing temperature; at equivalent temperature, higher load frequencies lead to a larger complex modulus, and this value increasingly decreases as the temperature increases; the phase angle increases with temperature and decreases as the load frequency increases. It can be concluded that the rutting resistance limiting temperature of crumb rubber modified asphalt is 78 °C, and the anti-fatigue limiting temperature is 16 °C, which shows that the asphalt has preferable rutting resistance characteristics at high temperature, as well as anti-fatigue characteristics. In addition, the complex modulus master curve at different temperatures was plotted according to the time temperature equivalence principle, which allows the study of the dynamic state behavior of crumb rubber modified asphalt at a wide range of load frequency.

Atmospheric exposure tests including two experimental stages of high temperature-spraying water cycle and heating-refrigeration cycle were carried out on three currently used ETIS of expanded polystyrene (EPS) board, polystyrene granule mortar and polyurethane foam in order to study the weatherablility of external thermal insulation system (ETIS). The change rules of adhesive strength were hereby studied at different time period of atmospheric exposure tests. The experimental results show that the adhesive strength of three kinds of ETIS changes a little during high temperature-spraying water cycle, but the adhesive strength of ETIS with EPS board decreases significantly after heating-refrigeration cycle. The lowering rate of adhesive strength with painting finishes is obviously faster than that of tile finishes for ETIS of EPS board during heating-refrigeration cycle. The weatherability of ETIS with EPS board is worse than the other two, and ETIS of polystyrene granule mortar and polyurethane foam are more suitable than ETIS of EPS board in cold area.

This research focused on using the waste rubber powder as a kind of regenerate resources to improve the mechanical properties of cement mortar. The two kinds of hybrid modified rubber powder TRP and ATRP were prepared by sol-gel method and then used in cement mortar. The structures and properties of them were studied. It is shown that the nano Si-O-Si network is generated in TRP and ATRP networks and the hydrophilic group is grafted on the surface of ATRP. The mechanical properties of rubber-treated mortar (RTM) were tested and the microstructures of them were also studied. Compared to the mortars with unmodified rubber powders (RP), NaOH treated rubber powder (SRP) and coupling agent treated rubber powder (CRP), the RTM with ATRP has the highest compressive strength and flexural strength. The stress-strain curves shown that the peak of stress of RTM with ATRP is increased and indicated the higher compression deformation and toughness. It is found that the interfacial adhesion between the ATRP and cement mortar is increased distinctly by SEM, which results in enhanced ductility and mechanical properties of RTM with ATRP.

Evaluation of high temperature performance of SBS-modified asphalt mixture was presented. Both wheel loaded method and creep method were adopted for two different mixtures and two kinds of specimens with different height, and corresponding indicators were measured. Meanwhile, the correlation between these indicators was thoroughly analyzed and two kinds of mixtures were compared. The experimental results show that there is a good linear relationship between LWT indicators and CT indicators for M-13, while a relatively poor relationship for M-25, especially that between dynamic stiffness and static stiffness and that between dynamic stability and static creep stiffness. Besides, logarithmic relationship between DS and RD has a higher determination coefficient than that for linear relationship. Thus, multi-index evaluation should be taken for synthetically assessing high temperature performance of asphalt mixture.

X-ray fluorescence spectrometry (XRF), X-ray powder diffractometry (XRD) and scanning electron microscopy (SEM) were used to characterize the chemical composition, phase constituent and microstructure of the coal gasification slag. Sialon powders were synthesized by carbothermal reduction and nitridation using the coal gasification slag as raw materials. The experimental results showed that glass and amorphous carbon were the main phases, quartz and calcite as minor crystalline phases were also presented in porous coal gasification slag. Main constituents of coal gasification slag were SiO₂, Al₂O₃, CaO and residual carbon. Sialon powder with Ca-α-Sialon as main crystalline phase can be synthesized when coal gasification slag powders were reduced and nitrided at 1500 °C for 9 h using nitrogen flow of 500 ml/min. The coal gasification slag is a valuable and economic starting material for preparing Sialon powders.

The aging mechanism of SBS modified asphalt during its aging process was studied. The characterizations of base asphalt, SBS polymer and its modified asphalt were determined in different aging time by Fourier transform infrared spectrum (FTIR). FTIR shows that oxidative dehydrogenation reaction occurs in asphalt, and unsaturated carbon bond is generated under short-term thermal aging condition. Additionally, SBS polymer was aged significantly under that condition, the speed of which was faster than that of base asphalt. The aging laws of both asphalt and SBS polymer during the aging process of SBS modified asphalt were similar to their aging laws respectively. Due to the protective effect between asphalt and SBS polymer, the aging degrees of asphalt and SBS polymer were lower than those aged independently.

The results of an experimental study on investigating the properties of cementitious rendering mortars prepared with a recycled fine aggregate (RA) were presented. The RA was obtained from a recycling plant in which mixed demolition wastes were processed by mechanical crushing, sieving and sorting operations. Two series of rendering mortar mixes were prepared with a constant water/cement and a constant aggregate/cement ratios of 0.55 and 3 respectively. River sand and natural crushed rock fine were originally used in the two series separately, and they were consistently replaced by 25%, 50%, 75% and 100% by the recycled aggregate. The experimental results showed that mechanical properties, such as compressive strength, flexural strength and modulus of elasticity of the mortars prepared with the RA were lower than the mortars made with the natural aggregates. Nevertheless, the bond strength at the interface between the mortar and masonry bricks determined by the Triplet test was found to be higher for the mortars prepared with the RA.

The shrinkage of the cement paste with low water-cement ratio at different relative humidity was observed and analyzed with ESEM and deformation map technique. The crack morphology was observed with different magnification with SEM and FESEM, and the formation of the crack was observed with AFM between two C-S-H nano particles. The observation by multi technique at multi scale indicated that the shrinkage was increase with the decrease of the humidity due to the increase of the pressure of the capillary pressure, the morphology of the crack in smaller scale was similar to that in the bigger scale, the smaller crack distributed in the latticework of the bigger ones, and the crack propagated along the gap between two nano particles of C-S-H with weaker bonding.

Qingdao Jiaozhou Bay subsea tunnel is the second self-built tunnel in China with the designed service life over 100 years. The durability of lining concrete are one of an important factors to determinate the service life of tunnel. Considering the main environmental loads and mechanical loads of subsea tunnel, the durability properties of lining concrete under combined action of compressive load and carbonation has been studied through the critical compressive load test, accelerated carbonation test, natural carbonation test and capillary suction test. The tests results show that critical compressive load apparently accelerates the carbonation and deteriorates the anti-permeability of concrete. Under the combined action of critical compressive load and carbonation, the durability of lining concrete decreases. Based on the carbonization life criteria and research results, for the high-performance concrete with proposed mix ratio, the predicted service life of lining concrete for Jiaozhou bay subsea tunnel is about 80 years which fails to reach the required service life. It is necessary to adopt other measurements simultaneously to improve the durability of lining concrete.

The effect of fly ash and early strength agent on resistance of concrete to the cyclic sulfate environment was studied. Concrete specimens made with ordinary portland cement or ordinary portland cement incorporating fly ash with the replacement of 10% or 20%, or 1% early strength agent and fly ash with the replacement of 20%, were made and subjected to 250 cycles of exposure to the cyclic sulfate environment. Concrete properties including loss of mass, chloride ion diffusion coefficient, compressive strength and flexural strength were measured. Microstructure and chemical component of samples were determined by means of X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The experimental results indicated that effect of fly ash on the cyclic sulfate resistance of concretes was mostly dependent on the amount of fly ash. Early strength agent improved performances of concrete with 20% fly ash exposed to cyclic sulfate environment.

The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder (PMB) successfully. To fully evaluate and understand the rejuvenation of aged PMB, the Penetration grade tests including penetration, soften point, ductility and elastic recovery and Superpave™ PG grade tests including DSR, BBR and DDT were conducted. The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated. And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated. The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation. But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well. Therefore, compound rejuvenation of polymer modified asphalt binder is recommended.

The moisture transport in cracked cement-based materials was investigated with priority by numerical simulation. The cracked cement-basis material was treated as two components system, including the cracks and cementitious mortar. The mass balance between the water in the cracks and in the cement mortar was considered. From the modeling results, it was seen that the water or vapor filled the crack immediately when the cracked cementitious mortar was put into contact with the water or vapor. The water/vapor penetrates into the mortar from the crack surfaces, as well as the external surface exposed in the outside condition. The existence of cracks increases the penetration of water/vapor into the cementitious mortar. As the basis for studying the self-healing in cracked concrete, the simulation on moisture transport provided important information about the water distribution and movement inside the cracked concrete.

Based on statistics principle, random error and systematic error were considered and the volumetric properties of the two mixtures types, namely A and B, were statistically analyzed using different distribution methods. Seventy-two samples of mixture A and fifty-two of mixture B were fabricated using the Marshall method. The probability distributions were compared on the basis of goodness of fit. Weibull model was found to be most appropriate model for describing the asphalt mixtures volumetric properties distribution. The two-parameter Weibull distribution function applied well to model the bulk specific gravity and voids filled with asphalt data, whereas, the three-parameter Weibull distribution appeared to be more appropriate in the discussing of air voids and voids in mineral aggregate. The experimetal results is revealed that compared with the mean value, the peak value of Weibull distribution was suggested as an alternative and more powerful parameter for describing the test data distribution characteristic. The analysis of test results also revealed that there were significant differences in the volumetric properties of the two tested mixtures for the same confidence level. The confidence interval decreased with the decreasing in reliability.