The data-driving method for glass composition design has become a desirable way to create novel glass materials, thanks to the ongoing development of machine learning algorithms and the progressive collection of glass materials. In the present work, the machine learning approach based on random forest regression algorithm was used to develop prediction model between the composition and performance of glass materials which contains 56 different oxides. In addition, the interpretability was studied by SHAP analysis. The accurate prediction of linear expansion coefficient, density, and elastic modulus in high-dimensional composition space was realized. The obtained models were utilized to forecast about 1.18 million Si-Al-B-Ca-Mg-Na six-component oxide glass composition swiftly. Four preferred borosilicate glass samples were tested. The results show that linear expansion coefficient of sample ranges from 52.00×10-7℃-1 to 58.00×10-7℃-1, the density ranges from 2.34 g/cm3 to 2.39 g/cm3, and the elastic modulus ranges from 67.00 GPa to 74.00 GPa, respectively. These values are consistent with the predicted values and outperform the applicable standards.

With the rapid development of scientific and technological level, the accuracy requirements for laser inertial navigation systems are becoming increasingly high. The quaternary PSN-PNN-PZT piezoelectric ceramics with large strain were prepared by the conventional solid-state synthesis method using industrial grade raw materials. The influence of different content Sr on the dielectric and piezoelectric properties of PSN-PNN-PZT piezoelectric ceramics was discussed. It is found that when the Sr content is 1% (mole fraction) and the molar ratio of n(Zr)/n(Ti) is 43/57, the PSN-PNN-PZT composition locates at morphotropic phase boundary and the piezoelectric ceramics show excellent properties. The large strain piezoelectric ceramics can be achieved, which are as follows: relative dielectric constant εT33/ε0=4 090, electromechanical coupling coefficient kp=0.664, piezoelectric constant d33=686 pC/N, dielectric loss tan δ=0.016 5, Curie temperature Tc=213 ℃. The strain of 24 mm×5 mm×0.4 mm piezoelectric ceramic thin rings based on this material formula reaches 2.500 5 μm at 100 V driving voltage, which is 32.4% higher than that of the existing PZT-14 (P14) material. This material can be applied in high-precision laser gyro frequency stabilizers to improve the reliability of piezoelectric micro-displacement actuator。

The preparation and performance optimization of concrete materials are the basis for the structural development and application of 3D printed building. The macroscopic mechanical properties and long-term durability of 3D printed concrete materials are directly related to the microstructure of interface. The formation mechanism of interlayer interface moisture state (water film) of 3D printed concrete was clarified, the evolution law of water film with time for different printing layer thickness strips was tested, the effects of time interval, printing layer height and environmental state on the pore characteristics of interlayer interface were studied by using CT scanning technology, and the interaction mechanism among interlayer interface moisture state, pore characteristics and binding performance was revealed. The results show that the interlayer interface porosity decreases with the increase of interlayer interface water mass per unit area, and the interlayer interface moisture quality is a more direct factor affecting interlayer interface state than the printing parameters. The interlayer interface moisture state and pore characteristics directly affect macroscopic mechanical properties of 3D printed concrete materials.

In order to develop the bonding and sealing materials for high integrity container with large flowability, high strength and high durability, so as to meet the requirements of 300 years service in a variety of harsh environments during the process of low and intermediate radioactive waste disposal, ordinary Portland cement and silica fume were used as cementitious materials, and fine quartz was used as intert filer. Based on the most compact stacking theory, preliminary formulation was obtained. Micro silica powder was introduced to partially replace cement, and rheological properties, pore structure, mechanical properties and durability of sealing materials were investigated. The results show that micro silica powder improves the fluidity and rheological properties, reduces the porosity at 28 and 56 d, and improves the splitting tensile strength, shrinkage resistance, chemical attack resistance, seepage resistance and freeze-thaw resistance of sealing materials, but the effect of micro silica powder on compressive strength and static elastic modulus is not obvious. After adding 10% (mass fraction) micro silica powder into cement, the properties of sealing materials are higher than those required by the Chinese standards and satisfies the demand of 300 years of service in harsh environment.

Silicon carbide whiskers (SiCw) has many excellent properties such as high strength, high elastic modulus. SiCw was dispersed by using water reducer as dispersant in order to modify cement-based composites. Through 8-shaped method, ring tests of crack resistance, and three-point bending test with pre-cracks based on the digital image correlation method, the fracture properties of materials were measured. The pore structure was studied by mercury intrusion porosimetry and the microstructure was observed by SEM to analyze its enhancement mechanism on cement-based composites. The results show that the SiCw causes crack deflection during crack propagation. By crack path analysis, the crack path of SiCw modified cement-based composites is more tortuous and consumes more energy while crack propagation than the blank group. The incorporation of SiCw helps to improve the brittleness of cement-based composites and provides new ideas for improving the performance of cement-based composites. The SiCw bridging effect and pull-out mechanism effectively control the crack propagation, thus enhancing the crack resistance and the tensile strength of the cement-based materials. From the perspective of pore structure, there is no obvious filling effect after SiCw incorporation. The addition of SiCw increases the total porosity of cement mortar slightly, which has no adverse effect on tensile strength and fracture thoughness.

To improve the performance of ultra-fine cement grouts (UFCG), multi-walled carbon nanotubes (MWCNTs) were added into UFCG. The effects of MWCNTs on the strength and grouting properties of UFCG, as well as the bond effect after MWCNTs being added and poured into concrete gap were tested. The results show that the optimum content of MWCNTs (10~20 nm) in UFCG is 0.10% (mass fraction). At this time, compared with blank group, the 56 d flexural strength, compressive strength, and their ratio of UFCG increase by 24.3%, 23.4% and 7.1%, respectively. With the increase of MWCNTs content, the fluidity of UFCG decreases, the viscosity and grouting pressure increase. It means that the grouting property decreases gradually. When the MWCNTs content is no more than 0.10% (mass fraction), the porosity of UFCG is not significantly improved, and the grouting effect is not significantly reduced. The result of splitting tensile test shows that the bond performance of UFCG and concrete is significantly enhanced after adding MWCNTs.

In order to investigate the effect of dolomite on the sulfate resistance of cement-based materials, the cement paste specimens and cement mortar specimens mixed by 10%, 20%, 30% (mass fraction, the same as below) dolomite were soaked in 5% MgSO4 solution and 5% Na2SO4 solution at low temperature, and sulfate attack test was carried out. Changes of the macroscopic morphology of specimens were observed regularly, and the erosion products were quantitatively analyzed. Flexural strength and compressive strength of cement mortar specimens were measured for macroscopic analysis, and the effects of different types of sulfates on the formation of thaumasite were obtained. At the same time, the effect of dolomite on the products of cement cementitious system was investigated by thermodynamic simulation. The results show that when the dolomite content is 10%~20%, the formation of thaumasite is inhibited, the sulfate resistance of cement-based materials is greatly improved, and the flexural strength of cement mortar specimens is significantly improved， which is consistent with the result of thermodynamic simulation.

The surface of steel fiber was modified by silane coupling agent (SCA), and the modified fiber was characterized by scanning electron microscopy and fourier transform infrared spectroscopy. The flexural properties and single-fiber pull-out properties of two SCA (KH560 and KH550) modified steel fiber cement-based composites were studied by bending tests and single-fiber pull-out tests. The results show that KH560-modified steel fiber can improve the early flexural strength and toughness of cement-based composites, single-fiber peak bonding stress and single-fiber pull-out energy. However, in later stages, KH560 deteriorates the steel fiber-matrix interface, which has a negative effect on flexural properties and single-fiber pull-out behavior. In contrast, KH550-modified fiber shows the opposite effect to that of KH560. The modified group with volume ratio of KH550 and KH560 of 5∶5 and 7∶3 can improve the early and late bending properties of steel fiber cement-based composites, and effectively improve the bonding performance of steel fiber-matrix interface. The composite SCA improves the roughness of steel fiber surface and facilitates chemical bonding at steel fiber-SCA-matrix interface. The composite SCA effectively improves the flexural strength and toughness of steel fiber cement-based composites.

In order to study the characteristics of water migration in cement mortar after high temperature, the surface of cement mortar samples was coated with wax (leaving an upper surface) after being treated at 300, 400, 500 ℃. Then the non-waxed end of samples was placed 2 cm below the liquid surface for self-imbibition test. The water migration state and characteristics of cement mortar samples after high temperature were studied by nuclear magnetic resonance (NMR) technology T2 spectrum and NMR imaging. The results show that with the increase of treatment temperature, the proportion of gel pores and air-voids or cracks in samples increases, while the proportion of capillary pores gradually decreases, and the water absorption mass of samples decreases. The water absorption mass increases rapidly in the first 24 h, then slows down and tends to be stable. The high temperature affects the capillary water absorption. When the treatment temperature is less than or equal to 400 ℃, the high temperature could increase the capillary water absorption. When the treatment temperature is greater than 400 ℃, the capillary water absorption is weakened. By introducing the capillary absorption coefficient S to characterize the capillary water absorption, S is greater than 10 before 6 h and decreases by more than two orders of magnitude after 6 h. There is a preferential pore size for water migration. The preferential pore size for migration in capillary pores is 10~480 nm, and the preferential pore size for pores or cracks is 1 680~16 800 nm. With the increase of immersion time, water tends to transfer from large pores to smaller pores. Finally, the migration position of water can be observed in real time from outside to inside by NMR imaging, and the migration speed is positively correlated with the temperature of samples.

In order to solve negative impacts of clay minerals on actual construction, the anti-clay polycarboxylate superplasticizer(PCE) was synthesized using acrylic acid(AA), isoamyl alcohol polyoxyethylene ether(TPEG), and hydrolyzed polymaleic anhydride(HPMA) as raw materials，and its structure was characterized. The dispersibility of PCE in paste, mortar, and concrete was tested under the conditions of adding different amounts and different types of clay minerals. The adsorption capacity of different clay minerals to PCE was measured by total organic carbon (TOC) analyzer.The interlayer spacing of three clay minerals interacting with PCE was tested by XRD. The results show that the order of negative effect and adsorption amount of clay minerals for PCE is montmorillonite > kaolin > illite. PCE interacts with illite and kaolin through surface adsorption, while it interacts with montmorillonite through interlayer adsorption amount.

The clay minerals attached to aggregate have serious deterioration effects on the workability of cement-based materials, which restricts the dispersion function of polycarboxylate superplasticizer. In this paper, the influence of polyaluminum chloride on the adsorption of polycarboxylate superplasticizer about clay was studied by Zeta potential, absorbance, and X-ray diffraction methods. And then, the improvement effect of polyaluminum chloride on the workability of mortar and concrete with calcium-based bentonite was studied, and the interaction mechanism was explored. The results show that polyaluminium chloride reduces the surface adsorption of calcium-based bentonite to polycarboxylate molecule, but it cannot inhibit the intercalation adsorption. The 6% (mass fraction) polyaluminum chloride improves the workability of mortar and concrete mixed with calcium-based bentonite. This behavior partly improves the clay resistance of polycarboxylate superplasticizer, providing a new strategy for solving the use of aggregate with high clay in practical engineering.

The effects of origin and aging ways on the composition, structure and macroscopic properties of lime were studied by X-ray fluorescence analysis (XRF), X-ray diffraction analysis (XRD), thermogravimetric analysis (TG), mercury intrusion test (MIP) and field emission scanning electron microscopy (SEM). The results show that the content of Ca and Mg in lime from different origin is also different. In the process of lime aging, aging way, origin and aging time all affect the grain size and crystal morphology of calcium hydroxide, and the grain size decreases with the increase of aging time. The effect of immersion aging is better than that of sealed aging and natural aging. Lime produced by immersion aging in Nanshilou area has a smaller grain size, higher activity and higher calcium hydroxide content by immersion aging preparation. More compact microstructure can be formed after forming hardening and curing, and it has better mechanical properties. This study will guide the preparation and engineering application of lime for ancient building repair.

In order to study the effect of clay powder in manufactured sand on the properties of mortar and concrete, mortar and concrete were prepared by replacing manufactured sand with different mass ratios using montmorillonite, kaolinite and illite. The working performance, mechanical properties and durability of mortar and concrete with different types and content of clay powder were tested. And the effects of clay powder types and content on mortar hydration products and pore structure were analyzed by X-ray diffraction (XRD) and mercury pressure (MIP). The results show that the incorporation of different types and content of clay powder reduces the working performance of mortar and concrete to varying degrees. Illite and kaolinite improve the mechanical properties and durability of mortar and concrete at lower content, and have a negative impact at higher content. Montmorillonite reduces the mechanical properties and durability of mortar and concrete at lower content. The incorporation of clay powder does not significantly change the main hydration product types of mortar, and the porosity, average pore size and cumulative pore volume of mortar increase with the increase of clay powder content.

In order to make better and safer use of abundant sea sand resources and alleviate the problem of river sand supply, the effects and mechanisms of different chloride ion content in purified sea sand on the compressive strength, carbonation resistance, sulfate corrosion resistance, corrosion degree of steel bars, chloride ion penetration resistance and electrochemical properties of C40~C70 concrete were studied through large-scale experiments. The results show that when the chloride ion content is less than or equal to 0.150% (mass fraction, the same below), with the increase of chloride ion content, the compressive strength of C40~C70 concrete increases and the later compressive strength continues to increase. At the same time, the carbonation resistance and chloride ion penetration resistance of C40~C70 concrete are also improved. When the chloride ion content is less than or equal to 0.060%, the sulfate corrosion resistance of C40~C70 concrete improves. When the chloride ion content is higher than or equal to 0.150%, the sulfate erosion aggravates. When the chloride ion content is less than or equal to 0.008%, the corrosion of steel bars delays. When the chloride ion content is higher than or equal to 0.060%, the corrosion of steel bars accelerates.

Considering the important influence of compressive strength on concrete design, an ISSA-GRU prediction model combining improved sparrow search algorithm (ISSA) and gate recurrent unit (GRU) was proposed to achieve accurate prediction of compressive strength of high-performance concrete. After normalizing the collected data set, the data set was divided into training set and testing set based on spectral-physicochemical value symbiotic distance （SPXY）method, GRU was used to predict the compressive strength of high-performance concrete, and enhances optimization efficiency of GRU network parameters by introducing ISSA with dynamic inertia weight. The results show that，in the case of using same data samples, the ISSA-GRU model is compared with the long short-term memory network (LSTM), kernel extreme learning machine (KELM) and support vector regression (SVR) models. The root mean square error (RMSE) is reduced by 93%, 375%, and 335%, respectively, and the mean absolute error (MAE) is reduced by 135%, 385%, and 417%, respectively. At the same time, the influences of the amount of training set data and input variables on prediction performance of the model were studied. The results show that the proposed model is efficient in finding GRU parameters, has high prediction accuracy and good adaptability, and provides a feasible reference for the development of diverse raw materials and specific properties of concrete.

According to the service environment characteristics of bridge pier concrete in plateau area, the effect of mineral admixture on concrete performance was investigated. The Box-Behnken Design response surface method (RSM-BBD) was used to design 15 groups of tests, and the effects of fly ash, slag and silica fume content on the strength and freeze-thaw properties of concrete were studied in detail. The response surface model was built with 28 d compressive strength, mass loss rate and relative dynamic elastic modulus of concrete after 200 times freeze-thaw cycles as response values to reveal the correlation between response parameters with target response values, and the optimal ratio of bridge pier concrete under multi-target response values. The results show that, compared with the concrete of reference group, the appropriate mineral admixture is beneficial to improve the strength and enhance the freeze-thaw resistance of concrete at low temperature. The strength and freeze-thaw resistance of concrete are mainly affected by a single factor, among which slag and silica fume can improve the compressive strength, while fly ash and silica fume can enhance the freeze-thaw resistance of concrete. The interaction of various factors has different degrees of influence on the performance of concrete. The interaction between slag and silica fume content has a significant effect on 28 d compressive strength. The interaction between fly ash and silica fume content has a significant effect on mass loss rate. The interaction between fly ash and slag content has a significant effect on relative dynamic elastic modulus. Based on target response values and response optimization, the reasonable ratio of mineral admixtures under the experimental conditions is 20%, 15% and 10% (mass fraction) of fly ash, slag and silica fume, respectively.

To study the effects of eccentricity and stirrup ratios on bearing capacity and bending ductility of glass fiber composite (GFRP) bars-coral concrete columns under eccentric compression， an eccentric compression test was carried out on 5 coral concrete columns. The effect of eccentricity on bearing capacity, GFRP longitudinal bar strain, concrete strain, vertical displacement and mid-span deflection was investigated and analyzed. Based on the five eccentricities above, 15 coral concrete columns were established and studied by ANSYS. Three stirrup ratios of 0.375% (stirrup spacing of 100, 75 and 50 mm respectively, the same as below), 0.500% and 0.750% were set in each group of eccentricity. Subsequently, the calculation methods of bending ductility and sectional curvature of these specimens were put forward in this paper. The results show that the increase of eccentricty not only decreases the bearing capacity, but reduces the increment speed of GFRP longitudinal bars strain on compression side. The increase of stirrup ratios not only improves the bearing capacity but also reduces the mid-span deflection of specimens.The theoretical calculated values of bearing capacity and bending ductility are in good agreement with the ANSYS simulated results.

Based on three-point bending test, the damage characteristics of notched beams of super absorbent polymer (SAP) concrete were researched at various loading rates. The fracture damage process was monitored by employing the acoustic emission (AE) technique. Variation of peak energy and cumulative energy were calculated by using the load-crack mouth opening displacement (P-CMOD) curves, and the damage mode of AE signals released during the damage of notched beams was analyzed by RA-AF correlation analysis. The results indicates that the strength of SAP concrete increases and the proportion of tensile-type fractures significantly decreases with the increase of loading rate. With the increase of SAP content, the strength of SAP concrete decreases at an equivalent loading rate, and the proportion of tensile-type cracks increases first and then decreases. Appropriate SAP can increase the proportion of tensile-type cracks. The research results can provide reference for the practical application of SAP concrete in engineering.

By adding 0.3% (volume fraction) polyvinyl alcohol (PVA) fiber into C30 concrete, the full immersion-drying tests under the action of different concentration of solution were carried out respectively, so as to explore the performance of anti deterioration performance of PVA fiber concrete. Taking deterioration test data as original sample value, GM (1,1) model, BP neural network model and GM (1,1)-BP neural network combination model were established respectively to compare the fitting accuracy of sample data. The relative dynamic elastic modulus after 35~50 cycles was predicted, and the overall change trend was analyzed. The results show that the evaluation indexes of concrete specimens change most stably in 10 times of the reference concentration solution, indicating that the specimens with 0.3% (volume fraction) PVA have better anti deterioration performance in high concentration solution. GM (1,1) model can accurately predict the overall trend change of sample. BP neural network model is more accurate in predicting the change trend of single sample point, with the highest overall accuracy. The combination model overcomes the shortcomings of two single models and has the best prediction effect. The predicted value of combination model is consistent with the change trend of test value.

Circulating fluidized bed fly ash (CFBA) was used to replace pulverized fuel ash (PFA). The effects of different CFBA substitution amount and cement content on compressive strength and dry density of autoclaved aerated concrete (AAC) were studied. Then, chemical titration, X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to explore the characteristics of delayed formation of ettringite (AFt) in AAC. The results show that when CFBA replaces 40% (mass fraction) PFA and cement content is 20.0% (mass fraction), AAC meeting the requirements of dry density grade B05 and strength grade A3.5 is prepared. When CFBA replaces 40% PFA and 100% PFA, the AFt content in 7 d air cured sample without autoclaved treatment reaches the maximum value of 7.71% (mass fraction) and 18.60%, respectively. After AAC obtained by autoclaved treatment and then air curing for 28 d, the amount of AFt delayed in sample is less than 1.00%. After AAC prepared by autoclaved treatment, and then soaked in water for 28 d, the AFt production in sample with CFBA replacing 40% PFA is 2.57%, and the AFt production in sample with CFBA replacing 100% PFA is 4.46%. The delayed AFt formed in AAC sample with CFBA replacing 100% PFA is a typical needle-rod crystal with high aspect ratio, which has the risk of volume stability.

In order to study the effect of circulating fluidized bed (CFB) fly ash on the performance of foam concrete, two different CFB fly ash and fly ash (FA) were selected, and the compressive strength, fluidity, pore structure and water absorption of foam concrete were measured. The influences of fly ash content and type on the properties of foam concrete were studied, and the micromorphology and phase composition of foam concrete were characterized by scanning electron microscopy and X-ray diffractometer. The results show that the high sulfur calcium content and irregular particle morphology of CFB fly ash will adversely affect the working performance of foam concrete. When low sulfur calcium CFB fly ash is added, the strength of foam concrete increases with the increase of CFB fly ash content, and the compressive strength of 7 and 28 d reaches the maximum value of 1.30 and 2.25 MPa at 50% (mass fraction, the same below) content. When high sulfur calcium CFB fly ash is added, the strength of foam concrete shows a trend of increasing first and then decreasing with the increase of CFB fly ash content, and the compressive strength of 7 and 28 d reaches the maximum value at 20% and 10% content, which is 1.42 and 2.00 MPa, respectively. The ettringite and C-S-H gel generated during the hydration process of CFB fly ash can fill the pores, increase the proportion of small pores, reduce the porosity, which is beneficial to increase compressive strength and reduce water absorption of foam concrete.

In order to study the effectiveness of the mesoscopic model, a mesoscopic continuous-discontinuous coupling model of coal gangue concrete circular-columns confined by glass fiber reinforced composite (GFRP) sheet was established by three-dimensional PFC-FLAC coupling method. The validity of the model was verified by experimental data. On this basis, the effects of 0, 2 and 4 layers of GFRP sheet on the axial compression performance, failure mode and energy absorption characteristics of coal gangue concrete circular-columns were studied. The results show that the established mesoscopic model has high accuracy. The ultimate failure strength of coal gangue concrete circular-columns increases with the increase of GFRP sheet layers. The energy absorption efficiency and volume specific energy absorption also increase with the increase of GFRP layers, but the proportion of increase decreases. The ductility characteristics of stress-strain curves, peak strength, failure mode, total energy density change, energy absorption efficiency and volume specific energy absorption of coal gangue concrete circular-columns are considered comprehensively, and the increasing layers can enhance the axial compression performance of the coal gangue concrete circular-columns, taking into account the principles of economic cost and winding level.

Taking quartz powder as a reference, the effects of fly ash and ground granulated blast furnace slag powder (GGBS) on the hydration process of magnesium phosphate cement were researched by monitoring the changes of hydration heat, suspension pH value and setting time. In addition, the compressive strength of mortar and pore structure of hardened paste were determined. The results show that fly ash as well as GGBS have strong delaying effects on the hydration of magnesium phosphate cement, and the delaying effect of GGBS is stronger. Fly ash and GGBS can improve the pore structure of hardened paste, and the improving effect of GGBS is more significant. When the replacement ratio is 15% (mass fraction), the compressive strength of magnesium phosphate cement containing fly ash or GGBS is higher than that of pure magnesium phosphate cement at 2 h. The compressive strength of magnesium phosphate cement containing fly ash is equal to or higher than that of pure magnesium phosphate cement at late ages. While the compressive strength of magnesium phosphate cement containing GGBS is significantly higher than that of pure magnesium phosphate cement at late ages.

The dry shrinkage and freeze-thaw cycle tests were conducted to discover the response characteristics of steel slag mixed soil base material under environmental conditions, the dry shrinkage strain, water loss rate, dry shrinkage coefficient, freeze-thaw mass loss rate and BDR were used as indicators, respectively. It is found that the 28 d dry shrinkage coefficient and freeze-thaw mass loss rate decrease, and BDR increases first and then decreases with the increase of steel slag proportion. It exhibits peak value of 96.1% when steel slag proportion is 50% (mass fraction), indicating that the appropriate steel slag proportion could not only restrain the dry shrinkage of steel slag mixed soil, but also endow it with better frost resistance. With the increase of cement dosage, the 28 d dry shrinkage coefficient and BDR increase, and the freeze-thaw mass loss rate decreases, which indicates that the increase of cement dosage is harmful to the dry shrinkage performance of steel slag mixed soil but is beneficial to its frost resistance. It is also found that soil curing agent can improve the drying shrinkage performance and frost resistance of steel slag mixed soil. SEM investigation implied that the steel slag mixed soil with 50% steel slag proportion and 5% cement dosage exhibits a closer structure and better integrity after 8 freeze-thaw cycles. By comparing the drying shrinkage coefficient and BDR of different base materials, it is found that the dry shrinkage performance of steel slag mixed soil is inferior to that of cement stabilized macadam, but is superior to that of cement lime stabilized soil, and the frost resistance reaches or even exceeds cement stabilized macadam.

In order to save cement resources and respond to the goal of “double carbon”, the use of industrial solid waste red mud and steel slag powder combined with cement to solidified fluid soil were explored. The working performance, compressive strength, electrochemical impedance spectroscopy and microstructure of the fluidized solidified soil with different red mud and steel slag powder content were investigated. The results show that the working performance of fluidized solidified soil can be regulated by changing the red mud and steel slag powder content. The slump increases first and then decreases with the increase of red mud content, when the red mud content is 10% (mass fraction), the slump reaches the maximum value of 203.0 mm. The setting and hardening time decreases with the increase of red mud content, the initial setting time ranges from 250 to 285 min. The compressive strength of fluidized solidified soil is mainly composed of hydrate calcium silicate (C-S-H) gel and ettringite generated by hydration reaction. At the age of 28 d, the compressive strength reaches the maximum value of 4.67 MPa, when the red mud content is 20% (mass fraction). There is a synergistic effect between red mud and steel slag powder, the addition of red mud and steel slag powder increases the production of C-S-H gel, and improves the mechanical properties of fluidized solidified soil. With the increase of red mud content, the arc radius of capacitive reactance, impedance modulus and phase angle peak, pore solution resistance Re and double electric layer capacitance Q all increase first and then decrease, and they all reach the maximum value when the mass ratio of red mud, steel slag powder and cement is 2∶3∶5. The results of electrochemical impedance spectrum and its equivalent circuit fitting are consistent with the variation law of compressive strength, electrochemical impedance spectrum technology is feasible in non-destructive testing of curing effect of fluidized solidified soil.

Using Baotou steel blast furnace slag as the main raw material and a small amount of chromite, microcrystalline cast stone was prepared by one-step heat treatment method in the cooling process of high temperature slag liquid. Through melting point measurement, differential thermal analysis, X-ray diffraction, scanning electron microscope observation and physicochemical properties test, the influence law of chromite addition amount on crystallization behavior and physicochemical properties of microcrystalline cast stone ware studied. It opens up a new way for low cost and high value utilization of Baotou steel blast furnace slag. The results show that: when the raw material ratio is 95% of blast furnace slag and 5% (mass fraction) of chromite, the overall crystallization of microcrystalline cast stone, the main crystalline phase is magnesium and aluminum feldspar, the bending strength is 31.88 MPa, the density is 3.439 g·cm-3, the water absorption rate is 0.036%, the acid resistance is 0.145%, the alkali resistance is 0.033%, in line with the national standards for building materials. It can completely replace natural marble and granite as architectural decoration materials.

Pervious concrete has significant pore characteristics, which can effectively solve urban waterlogging and conserve underground water systems. In view of the low compressive strength of pervious concrete caused by large pores, mineral admixtures were used to replace part of cement as cementitious materials in order to achieve the purpose of reducing production costs and improving compressive strength. In this paper, using fly ash, slag, metakaolin and other solid wastes as admixtures,compressive strength and water permeability tests were used to analyze the effects of single, double and triple-doped mineral admixtures on the properties of pervious concrete, and explore the hydration mechanism. The results show that the mechanical properties of pervious concrete with double-doped and triple-doped admixture system are significantly better than those of single-doped admixture system. When the content of fly ash, slag and metakaolin in triple-doped system is 15% (mass fraction, the same below), 15% and 10%, respectively, the property of pervious concrete is the best,of which the compressive strength is 22.1 MPa, and the porosity and water permeability coefficient are 14.3% and 3.27 mm/s, respectively, meeting the industry standards.

Based on the liquefaction phenomenon of tailings under seismic load, this paper proposes a method to enhance the seismic liquefaction characteristics of tailings, namely basalt fiber reinforced tailings. In order to verify the anti-liquefaction effect and mechanism of fiber reinforced tailings, a series of dynamic tests were carried out on fiber reinforced tailings silt by using dynamic triaxial apparatus. The effects of fibers with different length (3， 6， 9， 12， 15， 18 mm) under the same mass fraction (0.3%) and different mass fraction (0.1%， 0.3%， 0.5%， 0.7%， 0.9%) under the same length (9 mm) on the anti-liquefaction performance of tailings were studied. The results show that fiber reinforced tailings can effectively improve the liquefaction resistance of tailings. In terms of enhancing the anti-liquefaction effect of tailings, the optimal fiber length and optimal content are 9 mm and 0.3%, respectively. Through SEM images, it is found that basalt fibers are filled in the pores and fissures of tailings particles, and they are entangled and wrapped with tailings particles. Even some of the wrapped fibers are bent and interwoven with each other to build a three-dimensional mesh “bridge” bond.

Basalt fiber (BF) was blended into phosphogypsum-based composites (PGC), and the effects of BF diameter, length and content on the durability of PGC were investigated. The results show that the BF addition can significantly reduce the corrosion ratio of PGC. With the increase of BF content, the strength of samples in wet-dry cycle and freeze-thaw cycle increases generally, and the change mechanism is basically consistent with that of the absolute dry strength. The compressive strength and flexural strength in wet-dry cycle increase by 22.3% and 100.3% compared with blank group, respectively. The compressive strength and flexural strength in freeze-thaw cycle increase by 46.5% and 124.0%, respectively. At the same time, the dry-wet cycle and freeze-thaw cycle strength coefficients of PGC increase with the increase of BF content. The dry-wet cycle compressive strength and flexural strength coefficients increase to 095 and 092, and the freeze-thaw cycle compressive strength and flexural strength coefficients increase to 071 and 062, respectively, indicating that the durability of PGC has been significantly improved. In addition, the diameter of BF has no significant effect on the durability of PGC. The results provide a reference for the study of durability of fiber modified gypsum-based composites.

Through cube compression test, splitting tensile test, and three point bending test, the effects of high replacement ratio of recycled coarse and fine aggregate, and steel fiber content on the mechanical and fracture properties of recycled concrete were investigated. The cube compressive strength, splitting tensile strength, and double K fracture toughness of the sample for 28 d were tested, and the correlation between the basic mechanical properties and fracture properties of recycled aggregate concrete was analyzed. The computational relationships between the initiation fracture toughness, unstable fracture toughness, and splitting tensile strength of steel fiber reinforced concrete with large amounts of recycled aggregate were proposed. The results show that, the compressive strength and splitting tensile strength of recycled coarse and fine aggregate with a mass substitution ratio of 50% replace natural crushed stone and river sand and 1.0% volume fraction of steel fiber reach the highest, reaching 77.12% and 93.97% of those of natural concrete, respectively. After adding 1.0% volume fraction of steel fiber, the unstable fracture toughness of the test block significantly increases, and unstable fracture toughness exceedes that of natural concrete when the recycled fine aggregate content is 50%.

The share of water-based paint in the paint market is rising rapidly year by year, but there are some problems such as the low removal rate of water-based paint and secondary pollution in the treatment of water-based paint wastewater by traditional paint mist condensate. In this paper, a two-dimensional exfoliated montmorillonite paint mist condensate was developed, which significantly improved dispersion stability and removal rate of water-based paint in water-based paint wastewater of montmorillonite paint mist condensate. Atomic force microscope (AFM), scanning electron microscope-X-ray energy spectrum (SEM-EDS) analysis, Zeta potential analyzer, Fourier transform infrared spectrometer (FTIR) and ultraviolet spectrophotometer were used to explore the influence of two-dimensional exfoliation on the montmorillonite paint mist condensate and its mechanism. The results show that the mechanism of treating water-based paint wastewater by montmorillonite paint mist condensate is mainly that hydrogen bonds are formed between hydroxyl groups in montmorillonite, O in Si—O and carboxyl groups of water-based paint, so that water-based paint is adsorbed on the surface of montmorillonite. Montmorillonite with higher peeling degree has stronger electronegativity and can maintain better dispersion stability. With the increase of peeling degree, the dispersion stability and removal rate of water-based paint of montmorillonite paint mist condensate are significantly improved. When the dosage of two-dimensional exfoliated montmorillonite is 1.125% (volume fraction) of water-based paint wastewater and the dosage of cationic polyacrylamide is 1.000% (volume fraction) of water-based paint wastewater, the removal rate of water-based paint reaches 98.770%. Compared with the commercially available montmorillonite paint mist condensate, this product has higher removal rate of water-based paint after treating water-based paint wastewater.

Anhydrous calcium sulfate whiskers (CSW) were prepared by hydrothermal method using ammonium sulfate wastewater as raw material. The influences of sodium dodecylbenzene sulfonate (SDBS) and polyethylene glycol (PEG) with varying polymerization degrees on growth behavior of CSW were researched. Additionally, the molecular dynamics simulation of SDBS adsorption on the surface of CSW using Materials Studio 2020 software was simulated and the adsorption energy of each crystal plane was calculated. The results show that all products belong to CSW of orthogonal crystal system. CSW prepared without additives has an average length of 65.27 μm and an aspect ratio of 40. However, the surface is rough and the distribution is uneven. On the other hand, the CSW prepared by adding 4% (mass fraction) SDBS has the best morphology, uniform distribution, smooth, and needle-like surface, with an average length of 136 μm and an aspect ratio of 62. SDBS promotes the axial growth of CSW in the form of spiral dislocation, so that the aspect ratio of CSW is refined.

The seed solution was synthesized at 100 ℃ using tetrapropylammonium hydroxide as template and commercial silica sol as silicon source. Meanwhile, ZSM-5 zeolites with well crystallinity were successfully synthesized by adding seed solution in the template-free system, and the synthetic conditions of ZSM-5 zeolites were explored. The synthesized zeolites samples were characterized by X-ray powder diffraction (XRD), scanning-electron microscopy (SEM), N2 adsorption-desorption, fourier transform infrared (FT-IR), X-ray fluorescence spectroscopy (XRF) and ammonium temperature-programmed desorption (NH3-TPD). The results show that ZSM-5 zeolites are synthesized by adding only 0.5% (mass fraction) seed solution in the template-free system. Meanwhile, submicron-scale ZSM-5 zeolite aggregates with the size of ~500 nm are synthesized at 170 ℃ for 8 h under optimal synthesis conditions. Furthermore, in the isomerization of trimethylbenzene, the sample with n(SiO2)/n(Al2O3) ratio of 30 has better catalytic performance. Mass conversion of 1, 2, 4-trimethylbenzene, mass yield of 1, 3, 5-trimethylbenzene and selectivity of 1, 3, 5-trimethylbenzene are 3281%, 20.81% and 63.42%, respectively.

Thermally stimulated depolarization current technique can provide information on defect types that exist in the material systems, such as space charges, dipoles, trap charges and so on. Through TSDC spectral analysis, the properties of dipoles and movable ions, as well as activation energy, relaxation time and charged particle concentration, and other microscopic parameters, can be investigated to better understand the physical nature related to defects. This paper introduces the current application status of TSDC technique in inorganic materials reported at home and abroad. The research results and recent developments of TSDC technique in linear dielectrics, nonlinear dielectrics and ceramic polymer composites are summarized, in order to reveal the inner correlation between defects and properties in inorganic materials. It is expected to expand the application of TSDC technique in inorganic materials and provide new insight for the research on the microscopic mechanism of inorganic materials.

Silica sols were prepared by the sol-gel method using ethyl orthosilicate (TEOS) as raw material and ammonia as catalyst. The effect of ammonia addition on the particle size as well as the stability of silica sols were studied through SEM-EDS, XRD, thermogravimetric analysis, laser particle size analysis, Zeta potential, and other analytical means. The results show that when the pH value is in the range of 11~12 and the molar ratio of ammonia to ethyl orthosilicate R(n(NH3·H2O)∶n(TEOS)) is in the range of 1~10, the average particle size y of silica sol is index correlated with the R value x. The fitted function is y=2.22x1.79 with a correlation coefficient of 0.96, and the particle size increases from 1017 nm (R=1) to 142.48 nm (R=10), and the half-height width of the particle size distribution increases from 9.89 nm (R=1) to 171.61 nm (R=10). The stability of the silica sol shows a downward parabolic trend with the addition of ammonia, with the gel time decreasing from 684 h (R=1) to 28 h (R=5) and then increasing to 780 h (R=10).

Chemical strengthened lithium aluminum silicon (LAS) glass undergoes heat treatment steps such as curved surface forming and ion exchange during further processing, which affects its compressive stress distribution and structural strength. In this experiment, the influence of heat treatment process at 420~640 ℃ on the properties of LAS glass was investigated and characterized by single rod static pressure test, drop resistance test and Raman spectroscopy. The results show that the mechanical properties of LAS glass can be enhanced by heat treatment at the temperature range from the strain point 60 ℃ blow to the strain point, which is characterized by the increase of density, the increase of unit exchange stress, the decrease of compressive stress depth and the increase of static compressive strength of single rod. Raman spectrum analysis shows that the structure of the glass network is changed during the heat treatment process in this temperature range. The length of the silicon oxygen and aluminum oxygen tetrahedral bonds of the six-membered rings in the glass becomes shorter, and the structure of the linked network becomes denser. However, when the heat treatment temperature exceeds the strain point, the bridging oxygen between the silico-oxygen tetrahedrons begins to break, forming a relatively loose structure, and the mechanical properties decline.

Type Ⅳ silica glass is an important special glass material, which plays an important role in optical detection, inertial navigation and other fields. Optical homogeneity is an important way to characterize the structural homogeneity of optical glass, and the optical homogeneity of type Ⅳ silica glass is closely related to structural distribution consistency of silicon-oxygen network. In this paper, the radial distribution characteristics of hydroxyl, metal impurities and oxygen defects and the radial variations of silicon-oxygen bond angle were studied by four-step optical homogeneity test, ultraviolet-visible-near-infrared spectroscopy, infrared reflection spectroscopy, etc. And the influence of each affecting factor on optical homogeneity of sample was studied by correlation analysis. The results show that the wave aberrations t0Δn, which indicates the optical homogeneity of glass, decreases first and then increases along the glass radius. The radial distribution of hydroxyl is opposite to t0Δn radial variation as a whole. The radial variations of transmittance at 200 nm and silicon-oxygen bond angle are similar to t0Δn radial variation. The influence of hydroxyl on optical homogeneity of type Ⅳ silica glass is small, and the radial variations of metal impurities, oxygen defects and silicon-oxygen bond angle are the main factors affecting the optical homogeneity of type Ⅳ silica glass.

Controlled low strength material (CLSM) is a green backfill material which can self-compacting fill narrow space, facilitate secondary excavation and maintenance, and promote the utilization of solid waste resources. It can be used in pipe gallery backfilling and abutment back filling engineering. In order to improve the application level of solid waste materials in CLSM, scientifically and reasonably guide the composition design of CLSM material, and clarify the evolution law of CLSM working performance under the influence of multiple factors, the selection status of curing materials and curing base materials of CLSM were combed, the application status of solid waste materials in CLSM were summarized, and the relevant technical specifications and test standards related to the working performance of CLSM were compared and evaluated. The evolution law of flowability, bleeding rate, setting time and drying shrinkage of CLSM under the influence of different factors was clarified. In view of the remarkable progress made in the current CLSM-related research, the further research on CLSM composition design based on comprehensive performance regulation under different application scenarios is an urgent direction to promote CLSM engineering application.

In view of the difficulty of segregation evaluation methods of the existing cement stabilized macadam to accurately evaluate the situation of mixture segregation, the segregation resistance of five kinds of cement stabilized macadam mixture with different levels was quantitatively analyzed by indoor segregation test, and the shape segregation coefficient L and sieve segregation coefficient Seg were introduced to quantitatively classify the segregation degree of cement stabilized macadam mixture. The results show that compared to 4% (all are mass fraction) cement content, the segregation resistance of mixture with 5% cement content is significantly improved, and the segregation resistance of mixture with 5% and 6% cement content is not significantly different. Therefore, 5% cement content is more recommended. When the 4.75 mm pass percentage of mixture is 35% and 40%, a strong force chain structure is formed inside the mixture to resist the discrete trend of aggregate in the falling process, and the segregation grade of the mixture with 5% and 6% cement content remains in a state of no unsegregation and minor segregation, which demonstrates excellent segregation resistance of cement stabilized macadam.

In order to study the anti-aging effect of the hindered phenolic on the crack sealant system, hindered phenol 1076, butylated hydroxytoluene (BHT) and hindered phenol 1010 were used to modify the as-prepared ordinary sealants. Under the field condition, the crack sealant systems before and after modification were aged. Then, the performance changes, viscoelastic characteristics of the crack sealant before and after aging were compared, and the structural was characterized. The results show that the crack sealant modified with hindered phenol 1076 sustains anti-aging effect within 12 h of aging time. Hindered phenol BHT effectively inhibits the formation of polar groups and the increase of sealant’s modulus within 6 h of aging time. However, after aging for long time, the anti-aging effect of hindered phenol BHT declines obviously. Hindered phenol 1010 effectively inhibits the formation of carbonyl group after aging for 12 h but exhibits insufficient anti-aging effect within 6 h aging time. The anti-aging effect of the antioxidants is affected by its molecular structure, migration and the compatibility with the crack sealant system. The high compatibility, low steric hindrance effect and low migratibility are helpful for hindered phenol to improve the anti-aging property of crack sealant stably and efficiently. Isophorone diisocyanate can effectively improve the dispersion of hindered phenol in the crack sealant, further improving the anti-aging effect of the sealant system.