Table of Content

15 May 2017, Volume 36 Issue 5

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Sulfate Corrosion Resistance of Hybrid Fiber Reinforced Concrete

HE Rui;TAN Ya-wen;LI Dan;SHENG Yan-ping

2017, 36(5):  1457-1463. 

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In order to further improve the resistance of concrete to sulfate corrosion, under the condition of optimum mix proportion, the experiment of dry and wet corrosion and long-term immersion corrosion of concrete with different fiber content was carried out.The macro test methods such as morphology damage observation, mass loss, relative dynamic elastic modulus and compressive strength were adopted, to study the corrosion resistance of hybrid fiber concrete and its corrosion mechanism by SEM microstructure test.The results show that the concrete with different fiber content has different degree of damage under sulfate corrosion;the corrosion damage under the wet and dry cycle is more obvious than the long-term soaking corrosion.In the long-term immersion corrosion time of 450 d, the concrete has a compressive strength of 60 MPa, and the fiber concrete has a compressive strength of 70 MPa.However, in the dry and wet cycle corrosion, polyethylene fiber and polypropylene crude synthetic fiber mixed with 0.8%+1.2%, the concrete also has a compressive strength of 70 MPa.Fiber can alleviate the internal structural stress of concrete, disperse porosity, channel and other defects, as well as fiber bundles between the bridge are significantly improved the resistance to sulfate corrosion of concrete.

Preparation and Properties of the Porous Cordierite Ceramic for Catalystic Denitration

HE Feng;LIU Na;XIE Jun-lin;DONG Pan-pan

2017, 36(5):  1464-1469. 

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Porous cordierite ceramic was prepared by compression molding method with raw materials meta-kaolin, Al2O3 and talc and the denitration catalyst was obtained with impregnation coating method.The porosity, bending strength, thermal expansion coefficients, SEM, BET and other testing methods were used to investigate the effect of porous cordierite ceramics including type and content of the pore-forming agent and acid treatment.The catalytic performance was investigated with different loading rates between 80 ℃ and 200 ℃.The results show the cordierite owned excellent performance with the addition of carbon at 4%.In this condition, the porosity, bending strength and thermal expansion coefficients can reach 31.12%, 21.41 MPa, 3.10×10-6/K respectively.2 h is a perfect acid treatment time that can rich surface pore structure and enlarge surface area significantly.The integral denitration catalyst is obtained with excellent performance at low temperature when the impregnation time is 4.The firmness can be 90.18% and its efficiency of denitration will be 74.5% at 140 ℃.

Particle Size of Sol-gel-silica Microspheres by Response Surface Methodology

ZHANG Jia-hao;SHI Chao;SHAO Ya-wei;WANG Yan-qiu;LIU Bin;MENG Guo-zhe

2017, 36(5):  1470-1479. 

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The particle size of silica microspheres synthesized by sol-gel method was optimized by response surface method.The effect of single factor on particle size was studied and discussed.Based on the experimental conditions selected by the single factor experiment, the experiment was designed according to the response surface method.The data were analyzed by quadratic regression and variance analysis and the insignificant terms are deleted and refitted to make the model reflect the actual situation better.Based on the fitted model, the influence of the interaction was analyzed.The suitable range of sol-gel method and the synthesis conditions of specific particle size were predicted.It is found that the error value is within 100 nm, which can provide a good reference for the later researchers.

Freeze-thaw Cycle Performance of Pervious Concrete with Different Admixtures

ZHANG Jiong;LI Li;MING Rui-ping;MA Guo-dong;CUI Xin-zhuang;CUI She-qiang;WANG Zhong-xiao

2017, 36(5):  1480-1485. 

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Freeze-thaw damage of pervious concrete has been a serious problem which discourages its application in north China.To solve this problem, a series of experiments were carried out to study the effect of admixtures on compressive strength and freeze-thaw resistance of pervious concrete.Three admixtures, fly ash, ethylene vinyl acetate (EVA) latex and polyethylene fiber with different replacement of cement were used in this study, and physical properties such as permeability and compressive strength were tested.The freeze-thaw cycle tests were conducted base on fast freeze-thaw test.Mass loss and dynamic modulus were chosen for evaluation index.The results indicate that positive effects are found on freeze-thaw resistance for pervious concrete specimens with the addition of admixtures, but the degree and mechanism of effects are different for different admixtures.

Compressive Strength Growth Model of Recycled Concrete Powder Mortar

LI Qin;ZHANG Chun-hong

2017, 36(5):  1486-1491. 

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The research was carried from the strength law of the water cement ratio law of cement base material: the ratio of the strength is equal to the water cement ratio of cement base material.The relation between the recycled powder mortar strength and cement dosage and curing age were experimentally established, on which cement and the diy curing agent LQ1 and LQ2 content were respectively researched in the recycled powder mortar.And the relation functions are got to describe the relationships.Then random experiments were adopted to inspect and correct relation validation curing agent LQ1, LQ2 solidified mortar.As a result, the effective prediction models of the recycled powder mortar strength increasing by LQ1, LQ2 cured are got.

Effect of Recycled Aggregates and Rubber Particles on the Properties of Pervious Concrete

XIE Wei;FAN Cheng-cheng;CHEN Ai-jiu;WANG Jing;GUO Xiang-cheng;GUO Wen-cheng;CAI Xiao-long;QIAO Guo-yong

2017, 36(5):  1492-1498. 

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Based on the influence factors of recycled aggregates and rubber particles on the basic properties of C20 pervious concrete, and then studied the influence made by recycled aggregates and rubber particles by measuring the porosity, permeability coefficient, compressive strength at 28 d, tensile splitting strength, elastic modulus of pervious concrete.Meanwhile, the test established the relationship model between the porosity and permeability coefficient, tensile splitting strength and compressive strength at 28 d, elastic modulus and compressive strength at 28 d using the fitting regression and comprehensive comparative method.

Heat Resistance of Foam Cement Fluid for Sealing High Temperature Fracture

2017, 36(5):  1499-1504. 

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The fractures with high temperature formed by heat damage of coal and rock are the main causes to the evolution and spread of the coal fire.The foam cement fluid is a new type material for preventing and controlling the coal and rock fractures with high temperature.The heat resistant property of foam fluid is the important technical parameters.Based on homemade testing system for foam fluid heat insulation performance, the thermal insulation property of foam fluid with different bracket height (2 cm, 7 cm, 12 cm, 17 cm, 22 cm) and injection thickness (20 mm, 40 mm, 60 mm, 80 mm) were tested.It is concluded that with the increase of test time, the cold surface temperature of all the foam fluids increase from 20 mm to 80 mm, however, the slope of temperature rise curve is bigger within the test time of 0-90 s.The distribution of heat insulation temperature is in a curved surface as a whole.Then the relations of thermal insulation temperature, injection thickness and hot surface temperature were fitted.Under the condition of heating, the morphology change of bubble liquid film shows that the foam fluid is unstable at 200 ℃.The effects that heating on drainage rate of liquid film were studied from three aspects including surface tension, viscosity of liquid film substrate and free water content.

Effect of Mineral Admixture on the Mechanical Properties of the RAC Activity

ZHANG Ming-ming;WANG She-liang;ZHANG Shi-min;ZHANG Bo

2017, 36(5):  1505-1511. 

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In order to study the mineral admixture on the properties of the RAC interface improvements, the 174 groups of 522 active mineral enhanced RAC mechanics performance test, analyzed the mineral admixture under different content and volume rate on mechanical properties of RAC and changed rule of the influence of the deformation performance.Research results show that the fly ash (FA) on the early compressive strength of RAC cube is larger, with the increase of the content of the cube, the cube compressive strength show different degrees of reduction.With the increase of water reducing agent (PS) and silica fume (SF), the decline increases.But the axial compressive strength, splitting tensile strength and flexural strength, enhancement effect is more obvious.Along with the change of FA,PS and SF levels, the peak strain decreases.However, the elastic modulus increases with the increase of FA and PS.

Experimental Study on Desulfurization Performance of Bayer Red Mud

ZUO Xiao-lin;LI Bin;HU Xue-wei;HU Yuan-wei;ZHANG Bao-hua;NING Ping

2017, 36(5):  1512-1517. 

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The desulfurization effect and mechanism of treatment of low concentration SO2 by red mud slurry were studied by means of a laboratory-scale bubbling reactor, XRD and so on.The results show that the red mud liquid can contain sulfur 362.7 mg/g within the National Discharge Standard when the solid-liquid ratio is 1∶20.and red mud can purify SO2 under acidic conditions with the red mud pH of reaction termination dropping to 1.58.The solid matter in slurry desulfurization process has played a greater role in desulfurization the desulfurization,and the mechanism of red mud could be divided into basic physical desulfurization phase and iron ion catalytic oxidation desulfurization phase.When the red mud for pH ≤4, the dissolution of iron ion by mud slurry in acidic conditions has promote the absorption of SO2, and the effect of promoting is catalytic oxidation.Meanwhile, the final product by the reaction of SO2 and red mud mainly is calcium sulfate and sodium alum.

Preparation of Soda Residue-Fly Ash-Based Grouting Surry and Its Influencing Factors

LIU Yu-fei;LIU Chun-yuan;ZUO Li-ming;PANG Yun-ze;ZHAO Xian-hui

2017, 36(5):  1518-1523. 

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To explore the way of rational utilization of soda residue,soda residue and fly ash were mixed according to certain ratio.And sodium silicate was mixed to prepare a kind of grouting slurry, used in curtain grouting engineering of mine.Nine groups of orthogonal test and the scope of soda residue sieving test were designed to analyses influencing factors.Results show that the concentration of sodium silicate has the most prominent influence on compressive strength, fluidity and final setting time, and the ratio of soda residue and fly ash has the most prominent influence on the stone rate within the scope of selected factor levels.The compressive strength is basically equal when soda residue is sieved less than 2 mm or 1 mm.The compressive strength is enhanced about 51% when soda residue is sieved less than 0.5 mm.The compressive strength is enhanced about five times when soda residue is sieved less then 0.25 mm.

Influence of Dolomite on Grain Growth and Performance of Proppant Prepared by Flint Clay

WU Ya-qiao;WANG Kai-yue;TIAN Yu-ming;LIANG Li-ping;HAO Jian-ying;ZHOU Yi;LI Guo-min;ZOU Xin-wei

2017, 36(5):  1524-1529. 

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Fracturing propping agents, which the grain diameter was 425-850 μm and could be able to work under clossing pressure 35 MPa, were prepared by sintering process with flint clay as a new material and dolomite as adjuvant material.The effects of dolomite addition contenton the grain growth and performance of propping agent prepared by flint clay were investigated deeply.The morphology structure and phase analysis of fracturing proppants were investigated by SEM and XRD.The volume/apparent density and breakage radio of different sample were tested many times.The results reveal that the addition of dolomite in ceramic proppant is helpful to boost mullite and can decrease volume/apparent density but the breakage radio is still below 9%.

Properties of SiO2 Antireflective Thin Film Prepared by Two Different Acid-base Composite Catalyzed

LYU Ting-ting;LIU Xing-sheng;HUANG Guo-lin;WANG Le-le;ZHANG De-fu

2017, 36(5):  1530-1535. 

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Two different methods of acid-base composite catalyzed were introduced, the transmittance, surface morphology and hardness of the antireflection coating were compared.The first method is adding HCl to prepare the film, compared with the film prepared by acid catalysis, the transmittance is improved, but the film surface is not uniform, which affects the light transmittance.The second method is the drop of acid sol preparation film, its high transmittance, large film hardness, and the surface of the film is even.The structure and surface morphology of the prepared films were characterized by IR, XRD and SEM.The results show that the films obtained by dropping acid sol are more stable and have the best transmittance and strength.

Surface Modification of Bamboo Flour for Polypropylene Based Composites

WANG Jian;DONG Jie;ZHU Bao-dong;ZHANG Jian-wei

2017, 36(5):  1536-1541. 

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The bamboo flour (BF)were treated with different modifiers, and bamboo flour/polypropylene(BF/PP)composites were prepared via melt extrusion process.The micro-structure and properties of BF were analyzed by TG/DTA, FTIR, XRD and AFM.The results show that surface treatment improves the heat resistance and specific surface area of BF, and some looser fiber bundles are formed as well.The SEM images of the fractured surface of BF/PP composites indicate that treatment of BF with KH-550 efficiently improves the interfacial adhesion between BF and PP resins that leads to the enhancement of impact strength of the composite increased by 83% compared with that of pure PP.

Effects of Gypsum with Same Content of P2O5 on Hydration Mechanism of Supersulphated Cement

YU Bao-ying;ZHAO Ri-xu;YANG Wen;WU Xiong

2017, 36(5):  1542-1547. 

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The effects of phosphogypsum, anhydrite and dihydrate gypsum with same content of P2O5 on hydration mechanism of supersulphated cement(SSC) were investigated, the P2O5 of anhydrite and dihydrate gypsum were incorporated by solubility and analytical pure P2O5.The compressive strength and pore solution pH value in various age of three series of SSC specimens were tested.And the differences of early hydration exothermic process were compared.The hydration products and microstructure were analyzed by XRD and SEM.Results show that compressive strength and pore solution pH value in various age of anhydrite and dihydrate gypsum incorporating with analytical pure P2O5 based SSC specimens are close together.Comparing with phosphogypsum based SSC, anhydrite and dihydrate gypsum incorporating with analytical pure P2O5 decrease the pore solution pH value in various age of SSC.And they slow down the early strength development of SSC, but obviously promote the long-term strength development of SSC.The exothermic analysis show that anhydrite and dihydrate gypsum incorporating with analytical pure P2O5 quicken the appearance of the second exothermic peak of SSC, and shorten the setting time of SSC.XRD and SEM analysis show that anhydrite and dihydrate gypsum incorporating with analytical pure P2O5 have a better activation effect than phosphogypsum on SSC, SSC paste with anhydrite and dihydrate gypsum incorporating with analytical pure P2O5 can produce more C-S-H and ettringite with higher density in late stage.

Effect and Mechanism of Amorphous C12A7 on Cement Early Setting and Hardening

WANG Yi-ren;WANG Dong-min;ZHANG Jiang-tao;LI Wen-ping;ZHAO Ji-hui

2017, 36(5):  1548-1555. 

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Since amorphous C12A7 has higher, metastable state chemical energy, it has a faster rate of hydration.The setting and hardening of OPC can be accelerated just by the existence of small amounts of C12A7.The effect of amorphous C12A7 mineral on OPC properties were studied.The effects of 0-2.0 ratio of C12A7/SO3 on OPC macroscopic properties including setting time, fluidity and early compressive strength were discussed.At the same time, the optimal C12A7/SO3 ratio carried out preferably by gray related degree method, and then its microscopic mechanism was analyzed by hydration heat, XRD, SEM.The results show that: adding amorphous C12A7 can accelerate OPC coagulated and reduce its fluidity.The effect of different ratio of C12A7/SO3 on OPC mortar early strength is different respectively, which can significantly optimized OPC earlier performance when C12A7/SO3 is 0.4.C12A7 can accelerate the hydrolysis of C3S, C2S in OPC.Reaction of hydration products including ettringite, C-S-H gel and calcium hydroxide cemente together, which play an important role in early hardening of OPC.

Dispersion of Yunnan Xishuangbanna Halloysite

ZHENG Jia-min;GUAN Jun-fang;LI Xiao-fan

2017, 36(5):  1556-1561. 

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The halloysite from Xishuangbanna in Yunnan Province was studied in this paper.By measuring the slurry viscosity, the impact of stirring intens, solid content and pH value on the dispersion of halloysite in water without dispersant was determined.Moreover, the influences on the dispersion of halloysite in water with three various dispersants were discussed.The result showed that all of the three kinds of dispersants had good dispersing ability to halloysite.The capability of dispersants to the viscosity decreases successively: sodium polyacrylate, sodium hexametaphosphate, Sodium pyrophosphate.The appropriate pH value of sodium polyacrylate was greater than 7, sodium hexametaphosphate greater than 6.2, and Sodium pyrophosphate greater than 8.2.

Preparation of Porous Ceramic Filter for Gas Filtration at High Temperature

LI Wei-liang;LYU Xiang-nan;ZHANG Hua;JIN Jiang

2017, 36(5):  1562-1566. 

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Filtering ceramic for high temperature exhaust gas was prepared by the half dry pressing molding using alumina fiber and glass powder as raw material and activated carbon as pore-forming agent.The effects of the glass powder content, pore-forming agent content and sintering temperature on the filtration resistance, bending strength and apparent porosity were studied.The raw material formula was optimized and optimum firing temperature was selected.The optimal formula is determined as 70wt% alumina fiber and 30wt% glass powder with addition of 25% pore-forming agent and 8wt% carboxymethyl cellulose.The suitable firing temperature is 1100 ℃.The porous ceramic filter prepared by optimum parameters exhibits the flexural strength of 8.9 MPa, filtration resistance of 95 Pa and apparent porosity rate of 59%.

Effect of ZnO on the Mineral Composition of Portland Cement Clinker

HUANG Yang-yang;QI Yan-yong;DENG Lei

2017, 36(5):  1567-1572. 

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Blank raw meal mixed with different 0.1%, 0.3%, 0.5%, 1.0%, 1.5% of ZnO respectively and sintered at 1300 ℃, 1350 ℃, 1400 ℃, 1450 ℃ to make clinkers.These obtained clinkers were characterized by glycerin-ethanol method, X-ray diffraction with the Rietveld method, and petrographic analysis.The results show that better burnability of cement raw meal doped with defined content of ZnO is observed;obviously, the absorption of f-CaO at low temperature is higher than that of industrial raw meal without mixing with ZnO.With the incremental dosage of ZnO in mineral compositions at different sintered temperature, the content of alumino phase is reduced;the dosage of ferrite phase is increased, the content of C3S (tricalcium silicate) is gradually increased.When the dosage of ZnO is 1.5% at 1450 ℃ the phase of C3S is transformed from M3 to M1.It can be seen from petrographic of sample clinkers after sintered at 1450 ℃ that with the contents of ZnO in raw meals adjust the crystal appearance to attain good microstructure of clinker.

Rheological Property of SiC Slurry

QU Ling;HUANG Qing;ZHANG Cong;YUAN Wen-jie

2017, 36(5):  1573-1576. 

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In order to prepare the SiC slurry for porous ceramics, the variation of the shear stresses and viscosities of SiC slurries with different mass fraction (40%-60%) were investigated.The results show that the isoelectric point of the slurry is about 3.6, and zeta potential value decreases with the increase of pH value, the dispersing effect of the slurry in the alkaline condition is better.The correlation coefficients are both above 0.98 by fitting the shear stresses of SiC slurries based on Casson equation.The limit viscosities and yield stresses increase with the increase of the mass fraction.When the shear rate reaches 100 s-1, viscosities of slurries with the mass fraction ranging from 40% to 55% are below 1 Pa·s.The viscosity of the slurry with the mass fraction of 60% is 2.1 Pa·s.

Experimental Study on Preparation of Fly Ash Ceramsite

LI Liang

2017, 36(5):  1577-1581. 

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Fly ash is the main solid waste discharged from coal fired power plant,and the fly ash is mainly used for concrete additive, and the added value is low.In order to improve the utilization value of fly ash, the research on the preparation of lightweight high strength ceramsite.At 1100 ℃, Lytag sintering new phase anorthite, at 1200 ℃, Shi Yingxiang dissolves into the sintering phase, Lytag sintering new phase augite, suitable calcination temperature control at 1100-1200 ℃ range.When the calcination temperature is increased to 1200 ℃, the cylinder pressure intensity reaches about 6.3 MPa, the volume density reaches about 1.6 g/cm3.When the P value is low, the sintering temperature of fly ash ceramsite is reduced, the ceramsite is easy to burn, when the P value is more than 10, the sintering temperature of fly ash ceramsite is too high, and the fly ash ceramsite is not easy to expand.

Reaction Mechanism of Rubber AsphaltBased on Deck Pavement Material

GAO Jing-jing;FAN Xing-hua

2017, 36(5):  1582-1589. 

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The interaction effects of CRM binders as a function of various reaction parameters were investigated.Dynamic shear rheometer (DSR) and gel permeation chromatography (GPC) were used in the study.CRM binders were produced using seven blending time, three blending temperatures, and four rubber contents.The results show that the interaction time and interaction temperature for CRM binders have significant effect on the binder properties.The longer time and higher temperature for interaction of CRM binders resulted in an increase in the high failure temperature and the viscosity.Different blending treatments have little change of the binder properties.The CRM percentage influence is statistically significant on the viscosity and G*/sinδ values.Also, the asphalt binder with higher CRM percentage shows a higher large molecular size (LMS) value, and the increase in CRM percentage is considered to result in the additional loss of the low molecular weight in the asphalt binder to the CRM.

Research Progress on Modification and Applications in the Material Fields of Calcium Sulfate Whisker

LI Mao-gang;YE Kai;LUO Kang-bi;LI Hu-ping;SU Yi;LI Guo-bin;MEI Yi

2017, 36(5):  1590-1593. 

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The calcium sulfate whisker, as a kind of inorganic powder material, is a high added value product of gypsum with the characteristics of excellent mechanics capability, environmental friendliness and low price.In this paper, the current study condition on surface modification of calcium sulfate whisker was introduced, and the applications of calcium sulfate whisker in the material fields such as polymer composites, catalyst, papermaking, asphalt, building cement, recycled aggregates concrete as well as friction material were also summarized.

Review on Improving the Transmittance of Photovoltaic Glass

GENG Tie;HU Jin-zhong;WEI Chuan-le;SHENG Jie;QIN Li-xiang

2017, 36(5):  1594-1598. 

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Energy shortage has become a major obstacle to the development of the world economy, the development of new energy has been widely agreed.As a kind of non pollution and renewable energy, solar energy has attracted more and more attention.The transmittance of solar photovoltaic glass plays an important role in the use of solar energy, so how to improve the transmittance of photovoltaic cells has become a major research topic in the photovoltaic industry.As an important part of the photovoltaic cell package, photovoltaic glass is a kind of glass product which is directly applied to the solar photovoltaic power generation component, and has the function of transferring and controlling the light, or exporting the current.The transmittance of photovoltaic glass is an important factor which affects the conversion efficiency of solar photovoltaic cells.However, it is affected by many factors, such as the content of metal in the glass, the pattern of the rolled glass and the preparation method of the glass surface film.This article introduces the factors that influence the light transmittance of photovoltaic glass and summarizes the methods of improving light transmittance and the study of these methods in detail, which provides the direction for the next stage of research.

Literature Review of Extracting Lithium from Lepidolite

LI Gen;YANG Jie;YANG Jing

2017, 36(5):  1599-1604. 

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As the lightest metal, lithium has a range of attributes that makes this metal become an irreplaceable candidate in series of fields.Extracting Lithium is becoming more and more considerable to meet the large amount of the global market''s demand.Lepidolite, one of the most important lithium resources, plays an important role in the industry of extracting lithium and producing lithium products through an efficient and effective way.Three latest methods of extracting lepidolite with different additives: acid, alkaline, and saline reagents are reviewed in this paper.At the same time, the advantages and disadvantages of each method are reviewed in details.The reaction temperature can be decreased via acid method while more alkaline matter is needed to neutralize the remaining acid and Al3+ is removed at the same time;The alkali method is more economic and environmental friendly, but the waste residue is hard to recycle completely;Different effects can be achieved via salt method by using different saline materials but it is also difficult to separate lithium due to the production of double salt.Using proper method in a particular circumstance can take the advantages of different methods.

Research Progress on the Microorganism Self-healing Materials in Concrete

WANG Xue;ZHAI Dian-dian;GUO Yuan-chen;SUN Yan

2017, 36(5):  1605-1608. 

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With the development of the use of a biological healing cracks technique, to study building the microorganism healing agent into concrete to carry the point of concrete healing positively is of great practical significance.This paper reviewed some research achievements and progress of typical building the microorganism healing agent into concrete to inducing generating mineral salt healing cracks technique, discussed the existing problems and engineering application research prospect of healing cracks technique.Finally the main problems to solve built-in microbial self-healing material repair technology were pointed out.The review shows that: the self-healing materials and technology are still in the research stage of the lab, so it is really used less in the engineering, so it is necessary to seek other low-cost and low-requirement microbial carriers.

Research Progress of Noble Metal and SiO2 Core-Shell Nanomaterials

ZHENG Xing-fang;CHEN Jing-wei;QIN Hao-dong;XIE Song-chen

2017, 36(5):  1609-1615. 

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The research progress and applications of several kinds of noble metals such as gold, silver, platinum, palladium and rhodium as core or shell from the aspect of monometallic, bimetallic or multimetal core-shell system were summarized.The synthesis of silica core-shell structures were enjoying ever-increasing research interests for their important properties and diverse applications, such as catalytic, optics, diagnosis, photothermal therapy, and so forth.The development directions in the future were also pointed out.

Research Progress of Template Effect on the Preparation of Mesoporous Silica

SONG Fang-xiang;LI Yan

2017, 36(5):  1616-1622. 

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Since the concept of template method was proposed, the template has been gotten rapid development in the process of synthesis of mesoporous silica.But the effect of the different template properties on the morphology, the pore size and the structure of mesoporous materials has not been sufficient summarized and used.Thus, it''s very important to provide an important reference about how to choose the suitable template to synthesis ideal mesoporous silica.Combining with the status at home and abroad in related research, the different preparation methods of mesoporous silica about how to choose template matching up the corresponding solvent system were reviewed, and the development of template and the application of the mesoporous silica were discussed.

Bonding Technique of Ceramics to Metals

XIAO Jie;ZHANG Zhen-zhen;SHEN Wei;ZHANG Rui-yong;REN Wei

2017, 36(5):  1623-1627. 

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Special ceramics, as a kind of structural meterial, have the characteristics of corrosion resistance, high hardness and high temperature resistance.The critical factor that lets special ceramics can fully display material function is the bonding technique of ceramics to metals.The characteristice of the bonding of ceramics to metals from atomic structure and physical matches and chemical compatibilities were analyzed.A number of available bonding processes were introduced in this review, including brazing, solid-phase diffusioning, transient liquid phase bonding, reaction forming and self-propagating high temperature synthesis, and the emphases were placed on their principles, characteristics, limitations, latest progress and application in engineering.Then on this basis, the progress of the bonding technique of ceramics to metals were reviewed and the possible development in the future was predicated.

Performance of Tire Rubber Ash Modified Asphalt

XUE Zhe;QIAO Yun-yan;SONG Li-fang;XIA Hui-yun;GAO Li-ning;CHEN Hua-xin

2017, 36(5):  1628-1633. 

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In order to analyze the performance of tire rubber ash(TRA)modified asphalt, the TRA was prepared by high temperature thermal decomposition and two kinds of matrix asphalt with different ash content(0%-5.0%) were used to prepare the TRA modified asphalt in this experiment.The three index of asphalt,dynamic shear rheometer (DSR), penetration index, viscosity, elastic recovery, thin film oven test (TFOT) and standard test method for separation were carried out to study the high temperature characteristics, low temperature performance, temperature sensitivity, viscosity temperature properties, elastic recovery, aging properties and storage stability of TRA modified asphalt.And scanning electron microscopy and fluorescence microscopy were applied to analyze the microstructure of TRA and the modification effect of the modified asphalt.The results show that the high temperature performance of asphalt with TRA can be significantly improved, which can also reduce the temperature sensitivity and improve the viscosity temperature performance;when the content of TRA is lower than 3.0%, the elastic recovery of asphalt is improved significantly, and the TRA modified asphalt has no significant effect on the low temperature performance, aging properties and storage stability.Therefore, the advisable addition of TRA is 3.0%.Meanwhile, the microscopic test show that the TRA particles are irregular honeycomb structure with sticky pores, which can adsorb asphalt and evenly distribute in the asphalt.

Mechanical Properties of Portland Cement-Copper Slag Compound Cementitious Material

DU Hai-yun;MA Qian-min;GUO Rong-xin;YAN Feng;LIN Zhi-wei;HE Ke-cheng;HUANG Li-ping

2017, 36(5):  1634-1638. 

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Portland cement-copper slag compound cementitious material was prepared by replacing Portland cement (PC) by copper slag at the levels of 5%, 10% and 15%.Water required for normal consistency, setting time, compressive strength of paste specimens, flexural and compressive strengths of mortar specimens of the PC-copper slag compound system were studied.XRD,TG/DSC and SEM-EDS were also used to analyze the hydration products and microstructure of the PC-copper slag system.The results show that the use of copper slag increase the water required for normal consistency and setting time of PC.The flexural and compressive strength of the material are also generally increased after adding copper slag.In addition to the generation of Fe(OH)3/Fe(OH)2 gel, the main hydration product of Portland cement-copper slag compound cementitious material is similar to that of PC.Compared to PC, Portland cement-copper slag compound cementitious material the microstructure of the latter became denser.

Experimental Study on Mechanics and Permeability Characteristics of Soil-cement under the Influence of Water Reducer

CHEN Di;WANG Jiang-ying;ZHANG Gui-jin;FU Xiao-shu

2017, 36(5):  1639-1645. 

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In order to have a more comprehensive study about the mechanic and permeability of the soil-cement under the influence of the additives, there was a series of tests based on the orthogonal design method with a overall consideration of the influence of moisture content, cement content, water reducing agent content, fly ash content and other factors.Then according to the test, the unconfined compressive strength and permeability coefficient were obtained at the age of 3 d, 7 d and 28 d respectively, and the influence law of various factors on test were mastered and the relationship between them was simulated by SPSS software.The test results show that the order about the three factors against the unconfined compressive strength and permeability coefficient are moisture content, cement content, water reducing agent content,fly ash content.With the increase of moisture content, the cement-soil compressive strength decreases gradually and the permeability coefficient constantly increasing while the impact trend of cement content on the contrary.With the increase of water reducing agent of the sample, the strength curves were under the opening parabolas while the permeability coefficient curves were "V" shape change.In the practical engineering need according to the corresponding engineering goal and combined with field test to determine the best mix.In the cement-soil mixed a moderate amount of fly ash had no obvious effect on the strength.But it can reduce the permeability of the soil-cement especially in short ages.

Preparation and Performance of 800 Density Grades Muck-ceramsite

GAO Rui-xiao;RONG Hui;WANG Hai-liang;SONG Wei-jun;QI Zhan-guo;LI Xiang-hai;DI Zhi-kun;ZHANG Lei

2017, 36(5):  1646-1650. 

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In order to further promote the utilization of municipal wastes, this paper developed a new type of ceramic powder with different density (10-15 mm, 15-25 mm).The effects of raw material formula and firing process on the properties of the ceramic particles were investigated.The microstructure of the ceramiste particles was analyzed by the ultra-depth optical microscope and scanning electron microscope.The results show that: When the mass ratio of fly ash to fly ash is 75∶25, the preheating temperature is 500 ℃, the preheating time is 20 min, the calcination time is 15 min and the calcination temperature is 1190 ℃.10-15 mm, 15-25 mm);Macroscopic properties: 15-25 mm particle size of the dregs of ceramic, cylinder pressure intensity of 4.6 MPa, bulk density 729 kg/m3, the apparent density 1329 kg/m3, 1 h water absorption rate of 1.7%, loss on ignition of 1.4%;10-15 mm particle size of the clay ceramic, cylinder pressure of 5.2 MPa, bulk density 760 kg/m3, apparent density 1483 kg/m3, (1.6%) and loss on ignition (1.4%).The microstructures of slag soils under different grain sizes were relatively loose.The internal structure of the small particle size ceramic is more loose than the large particle size, pore size is larger.

Preparation and Characterization of Montmorillonite Intercalated with Cationic Konjac Glucomannan

PENG Qi;ZHAO Dong-yang;HOU Meng-juan

2017, 36(5):  1651-1655. 

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Quaternized KGM (CMKGM) was used to modify montmorillonite (MMT) to prepare organic montmorillonite (CMKGM-MMT).The structure of modified montmorillonite was characterized by infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).The results show that quaternized KGM indeed intercalate into the layers of montmorillonite and form intercalated organic montmorillonite with the highest organic modification when the amount of CMKGM is equivalent to 1.0 CEC of MMT(the mass ratio between CMKGM and MMT is 0.9) under the condition of 60 ℃ at pH=4.6.Then the in vitro cytotoxicity and the drug loading property of the complexes were investigated.

Preparation of Refractory Material Based on Fly Ash

LI Jian-duo;MA Li-ping;LIU Hong-pan;WANG Rong-mou;CUI Xiao-jing

2017, 36(5):  1656-1660. 

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Fly ash based refractory materials with varied alumina content (by controlling the raw materials with different ratios) at different sintering temperature were prepared using fly ash as the main raw material and coal gangue and industrial alumina as the auxiliary materials.The structural performance of the samples was tested;the microstructure was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques.The results show that the compactness, mechanical properties, refractoriness as well as crystalline structure of the prepared refractory material are affected by both sintering temperature and alumina content.Desirable performance of bulk density 2.47 g/cm3, compressive strength 41 MPa, refractoriness 1450 ℃, and mullite and corundum as crystalline state are observed for the sample prepared at sintering temperature of 1350 ℃ and alumina content of 45%.The application of fly ash in refractory material preparation is meaningful in producing high-value added products with it.

Mechanical Properties and Hydration Products of Molybdenum Tailings Based Mortars with Super Plasticizer

CUI Xiao-wei;DI Yan-qing;NAN Ning;LIU Xuan;ZHOU Chun-sheng

2017, 36(5):  1661-1666. 

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A cementitious material was prepared with blended powders including molybdenum tailings, slag, clinker and gypsum.The effect of different types and dosage of super plasticizer on strengths and hydration products of molybdenum-tailing-based mortars was studied.The results indicate that the strength of mortars with the same fluidity is improved when super plasticizer is present in samples.The biggest improvement is PC super plasticizer, next one is FDN and the last one is UNF-5.When the dosage of PC super plasticizer is 0.4%, the compressive strength of molybdenum-tailing-based mortars is high up to 48.8 MPa at 28 d.The ground molybdenum tailings have a certain reactivity in the studied system.The hydration products of cementitious materials prepared with molybdenum tailings are mainly ettringite and C-S-H gel.

Performance Influence on Different Component Formulas of Intumescent Flame Retardants

ZHAO Jiang-ping;WU Dan;WANG Ya-chao

2017, 36(5):  1667-1672. 

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Ammonium polyphosphate, pentaerythritol, urea and polyester resin were used as the intumescent flame retardants agent of acid source, carbon source, gas source and film former.Exploring the influence of each component on the flame retardant performance in primary and secondary order based on orthogonal experiment, the small chamber combustion and limit oxygen index test, measure the effect of the intumescent flame retardant under different formulas.The results show m(ammonium polyphosphate)>m(polyester resin)>m(urea)>m(pentaerythritol),which is 9# formula A3B3C2D1, samples treated by this formula, the oxygen index obviously rise to 38%.At the same time, the combustion process was analyzed through TG and SEM analysis, and the mechanism of the intumescent flame retardant was explained.

Grouting Performance of Ordinary Cement and Superfine Cement and Comparison of Grouting Effect in Loess

ZHOU Ming-ru;PENG Xin-xin;SU Bo-tao;FAN Le-tao

2017, 36(5):  1673-1678. 

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Through the analysis of water separating rate, viscosity, stone body strength, durability and other tests on the two kinds of grouting materials of Portland cement and superfine cement, the experimental results show that the superfine cement has better stability and lower viscosity when the water cement ratio is greater than 0.8.The strength of the stone body is higher and the density of the stone has a compact structure and good durability.In the simulated grouting test of loess, the effect of grouting is summarized.The two kinds of grouting materials are similar to splitting soil in shape, to verify compliance with the laws of mechanics.Through soil mechanics experiment, the superfine cement squeeze better density of soil than Portland cement.It''s obvious that the shear strength of the soil is improved, and the compression ratio is lower than that of the Portland cement grouting soil.The results show that the superfine cement is more suitable for the prospect of grouting loess.

Preparation and Dielectric Properties of CeO2-doped Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 Ceramics

MA Wu-xiang;DU Hui-ling;HAO Xing-chen

2017, 36(5):  1679-1685. 

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In order to further explore the effect of synthesis process on structure and dielectric properties of the sodium bismuth titanate lead-free materials, thus, taking glycine as fuel, cerium-doped Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 (BNKT) ceramics were prepared by the solid-combustion composite method.X-ray diffraction (XRD) data shows that the calcined temperature, combining the combustion method in solid phase synthesis process, declined by 150 ℃ than that of conventional solid state method and CeO2 diffused into the lattice of BNKT ceramics, as well as the pure perovskite phase was formed while the amount of CeO2 was 0%-0.3%.SEM images indicate that the doping of CeO2 made grain crystal size uniform and restrained crystal grain growth.The temperature dependence of the dielectric constant and dissipation factor shows that the dielectric constant εr, depolarization temperature Td and the inversion temperature Tm of the antiferroelectric to ferroelectric phase decreased with addition of CeO2, and also the dielectric peak was weakened gradually and the dielectric loss tanδ is below 0.3% between room temperature and 300 ℃.Furthermore, combining microstructural vacancy mechanism with ferroelectric domain wall movement, the law of function is discussed and analyzed.

Pore Structure and Carbonation Fractal Characteristics of Waste Fiber Recycled Concrete

ZHOU Jing-hai;KANG Tian-bei;WANG Feng-chi

2017, 36(5):  1686-1692. 

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The design variables of the experiment were water cement ratio, recycled aggregate replacement ratio, waste fiber length and volume content.The fractal characteristics of pore structure and carbonation performance of waste fiber recycled concrete were investigated by mercury injection test and rapid carbonation test.The results indicate that waste fiber recycled concrete pore structure has a prominent fractal characteristic, the addition of waste fiber can prevent the formation of harmful pore structure, and improve the waste fiber recycled concrete pore structure inside.The waste fiber can improve the carbonation resistance of recycled concrete and the optimal volume content is 0.12%, the smaller fractal dimension of the carbide boundary contour, the greater carbonation depth.There is a correlation between the depth of carbonation and pore volume fractal dimension of recycled concrete waste fiber.As the pore volume fractal dimension decreases and carbonation depth increases, it is feasible to evaluate different design variables of waste fiber recycled concrete carbonation depth according to the pore volume fractal dimension.

Optimizations of Thermal and Mechanical Properties of Silica Aerogel Composite

LIANG Yu-ying;WU Hui-jun;HUANG Ren-da;YANG Jian-ming

2017, 36(5):  1693-1699. 

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As a novel type of nano porous materials,silica aerogel has exhibited extensive application prospects in thermal,optical and electrical and other industrial fields owing to its super-low thermal conductivity.However,its thermal insulation performance in high temperature and mechanical behavior are poor.Commonly they could be improved by adding additives of opacifiers and fibers into aerogel matrix to form three-component aerogel composite.In the progress of improving,component contents significantly influences the thermal and mechanical properties.Therefore this study is aiming to investigate the effect of the component contents on thermal conductivities and mechanical properties based on theoretical models.The ternary orthogonal design method was used to optimize component contents,and thereby to provide guidance engineering area of component contents for satisfying the engineering requirements of thermal and mechanical properties simultaneously.

Experimental Study on Chloride Diffusion under the Effect of Flexural Tensile Load and Carbonization Coupling

CHENG Yang;SUN Jia-ying;ZHENG Ming

2017, 36(5):  1700-1705. 

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In order to solve the transmit problem of chloride ion in concrete under the composite effect of flexural tensile load and carbonization in the salt fog area, experiments were designed to study the impact of flexural tensile load and carbonization on the chloride diffusion,respectively.Moreover,since flexural tensile load can influence the carbonization process,which further impacts the chloride ion diffusion,the experiment of load''s impact on the carbonation depth was also designed for the research.With Fick''s Second Law as the benchmark model, a new model of chloride ion diffusion under the composite effect of flexural tensile load and carbonization has been constructed based on the above experiment data as well as existing studies.This model have some positive sense when to predict the flexural member service life in the salt fog area.Experiment outcomes are in line with the results calculated based on the theoretical model with a minor error of under 5%,which further illustrates the validity of step-by-step model construction.

Triethanolamine Salinized by Monoprotic Organic Acids Cement Grinding Aids

ZHANG Jian-li;ZHANG Chang-sen;FENG Zhen-zhe;ZHU Bao-gui;LI Yang

2017, 36(5):  1706-1712. 

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In order to reduce the cost of using triethanolamine and improve its grinding and strengthening effect, DOGA series cement grinding aids were synthesized by salinizing triethanolamine with monobasic organic acid.The effects of DOGA series cement grinding aids on cement properties were studied by analyzing the specific surface area,sieve residue,particle size distribution,TG-DSC and compressive strength of cement hardened paste.The results show that DOGA series cement grinding aids improve the grinding and strengthening effect, a reference sample is made with triethanolamine,and DOGA3 has the best grinding and strengthening effect.When the added amount of DOGA3 is 0.05%, 45 μm sieve residue decreased by 21.1%, specific surface area increased by 21 m2/kg,3-32 μm increased by 2.14%, 3 d and 28 d compressive strength increased by 2.1 MPa and 4.4 MPa, respectively.

Preparation and Effect of Coal-gangue Admixture on Alkali-aggregate Reaction of Concrete

ZHOU Mei;SHEN Meng-yang;WU Jing-hao;GAO Shuo;SUN Xiao-hong;LIU Xin;NIU Meng-en;ZHANG Jia-qi

2017, 36(5):  1713-1717. 

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The effects of calcination temperature, constant temperature time and cooling mode on the activity of unburned coal-gangue were studied by strength evaluation method, and the coal-gangue admixture was prepared and compared with fly ash and slag on performance.On this basis, the influence of fineness and content of coal-gangue admixture on mortar consistency and alkali-aggregate reaction was studied by its mortar fluidity and accelerated mortar bar test.The results show that coal-gangue powder with mechanical and thermal activation has the effect on micro-aggregate and activity, which can improve the consistency of the mixture and inhibit the expansion of the concrete, and the inhibitory effect of fineness is more obvious.The work-ability of concrete with the local coal-gangue admixture is improved and the inhibition of alkali-aggregate reaction gets the best effect, when the local coal-gangue calcined at 750 ℃ for 3 h, the fineness is 1150 m2/kg and the content is control in 5%.

Influence of Biomass Ash on the Compressive Strength of Hardened Cement Paste

LIU Yong;FENG Jing-jing;YU Lei;LIU Yang;YANG Guang-shuai;WANG Shun

2017, 36(5):  1718-1722. 

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The difference between biomass ash and fly ash on the particle size distribution, particle morphology, chemical compositions and activity index was studied.Cement mortar tests adding different biomass ash contents were conducted to evaluate the compressive strength of hardened cement paste.The results show that the particle shape of biomass ash is irregular, the average particle size and particle size distribution range is larger.It has the slender fibrous particles, and the active components of Al2O3 are less than a third of the ordinary fly ash.The pozzolanic activity of biomass ash is lower than fly ash.Under the same content, the compressive strength of biomass ash-cement complex mortar is less than fly ash-cement complex mortar at all ages, the more dosage, the greater the strength decreased degree compared with the pure cement group.The microstructure of adding biomass ash of hardened cement paste is more loose and porous than the sample of containing fly ash, especially the existence of its peculiar slender fibrous particles.

Effect of Steel Slag on the Mechanical Properties and Durability of Concrete

DING Tian-ting;LI Qi-hua;CHEN Shu-dong

2017, 36(5):  1723-1727. 

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The effect of different content of steel slag on the compressive strength and flexural strength of concrete was studied based on the micro aggregate and active effect of steel slag.The carburization resistance and freeze-thaw resistance of steel slag concrete were investigated by carbonization test and frost resistance test.The pore structure of steel slag concrete was investigated by X-CT.The results show that the compressive strength and flexural strength of concrete with content 10% steel slag is the highest, and the compressive strength and flexural strength of content 30% steel slag is the least.The carbonation depth of concrete with 30% steel slag has reached 12.5 mm when carbonized to 56 d.The relative dynamic elastic modulus of concrete with content 30% steel slag is reduced to 88.7% after 180 d of freeze-thaw cycles.

Experimental Study on Dynamic Parameters of Modified Aeolian Sand with Lime-Fly Ash at Negative Temperature

ZHANG Xiang-dong;HU Xiao-fei

2017, 36(5):  1728-1734. 

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In order to study the dynamic characteristics of modified aeolian sand under low temperature, the modified Hardin hyperbola model was used.And this paper was based on the dynamic triaxial test of frozen soil, the dynamic mechanical parameters of lime-fly ash aeolian sand with different experimental conditions under negative temperature were studied.The results show that the dynamic shear modulus of modified aeolian sand increases first and then decreases with the increase of the ash mixing ratio, and the improvement effect is best when the ash content is 30%-40%.Under the same mixing ratio, the dynamic shear modulus of frozen soil increases with the increase of confining pressure and frequency, and decreases with the increase of freezing and thawing cycles and temperature.The maximum dynamic shear modulus of the aeolian sandy soil under negative temperature was regressed by regression analysis.The linear equations of maximum dynamic shear modulus and confining pressure, frequency and temperature are obtained.The results can provide a scientific basis for solving practical engineering problems, and have certain social and economic benefits.

Friction Stir Welding of Packaging Container Made of SiCp/Al Compositeswith Low Volume Fraction

GAO Zeng;CHENG Dong-feng;WANG Peng;NIU Ji-tai

2017, 36(5):  1735-1739. 

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SiC particle reinforced aluminum metal matrix composites (SiCp/Al MMCs) has excellent properties, which is very promising in many fields.However, the poor weldability is the bottleneck problem for its wide application.Using friction stir welding (FSW), the packaging container made of SiCp/Al MMCs with low volume fraction was welded successfully in this paper.In this experiment, FSW-tool was a cone shaped wear resistant WC-Co tool with shoulder diameter of 10 mm, base cone diameter of 5 mm, cone tip diameter of 3 mm and cone height of 2.5 mm.Welded joint with good quality at both surface and internal could be obtained under the optimal process parameters: pressing force 2 kN (force controlled), tool tilt angle of 3°, spindle speed of 1500 RPM, transitional speed 120 mm/min and plunge depth of 2.55 mm.After FSW processing,SiC size in stir zone became smaller and its distribution in this area was more homogeneous.Moreover, the common defect in FSW joint such as hole, groove were free from in the stir zone.A large number of distorted structures in thermal-mechanical affected zone can be found.This is mainly due to the elongation of base metal structure and then followed by plastic flow.The highest average hardness value in base metal is 61.9 HV3.The average hardness in stir zone is 58.3 HV3.The lowest average hardness value in thermal-mechanical affected zone is 55.4 HV3.

Preparation and Properties of Nickel Slag Based Foam Glass

FENG Zhen-zhe;WU Qi-sheng;ZHANG Chang-sen;ZHANG Jian-li;ZHU Bao-gui;LI Yang

2017, 36(5):  1740-1745. 

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Foam glasses were prepared through the mold filling method using nickel slag and waste glass as the main raw material and Na2CO3 as foaming agent.The effects of nickel slag content, foaming agent content, foaming temperature and sintering time length on the structure and mechanical properties of the foam glass were investigated.The experimental results show that a decrease in volume density and an increase in average pore size of foam glasses with a decrease in the content of nickel slags, an increase in Na2CO3 content or an increase in sintering temperature;Composition and crystalline phase type of foam glass were barely affected by change of nickel slag content.The foam glasses exhibited excellent comprehensive properties such as a porosity of 85.14%, an apparent density of 0.3715 g/cm3, a bending strength of 2.062 MPa, and an average pore size of 3.13 mm when using 20% nickel slags and 80% waste glass as main raw materials and 5%-7% Na2CO3 as gas blowing agent at 870 ℃ for 60 min.

Determination of SO3 in the Cement Products by the Handheld Energy Dispersive X-ray Fluorescence Spectroscopy

WANG Jin-zhuan;ZHOU Jun-gui;WU Hai-juan;LIANG Zhi;HUANG Zhen;XIA Qian-feng;WANG Bing

2017, 36(5):  1746-1749. 

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The performance of cement is closely related to the content of SO3 in the cement products.So, the determination of SO3 is particularly important.The handheld energy dispersive X-ray fluorescence spectroscopy(EDXRF) was applied to determination of SO3 in the cement samples, the test conditions of SO3 were optimized, and the calibration curve was built.The result shows that linear relationships within values of fluorescence intensity and mass fraction of SO3 were found in the same range within 0.31%-3.16% in the standard samples of eight different kinds of Portland cement, and the correlation coefficient was greater than 0.99.The proposed calibration curve was used in testing the content of SO3 in the ordinary and composite Portland cement samples, giving test results of EDXRF inconsistency with that of the standard method.

Experimental Study on Performance of Eco-porous Concrete

QUAN Hong-zhu;SHEN Yang;ZHOU Guang-xing;PANG Zeng-ming;YANG Ya-nan

2017, 36(5):  1750-1754. 

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To find out the influence rule of mixing proportions on performance of eco-porous concrete, eco-porous concrete with different water-binder ratio and design porosity were produced and tested, and the mechanical properties were tested.Planting test was implemented to find the suitable one from 6 tested species.In conclusion, eco-porous concrete has lower strength in early age and higher target porosity.Compressive strength decreases with the design porosity.Strength and water-binder ratio prove to have weaker relationship for low density eco-concrete.Tested porosity increases with water-binder ration.All tested grass species grew normally in eco-porous concrete except Bermuda, Red Fescue and Agrostis tenuis, and Tall Fescue is best fit for eco-porous concrete.

Oxidation Resistance of MgAlON Composites

GUO Yan-qin;ZHANG Hai-yan

2017, 36(5):  1755-1759. 

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Experimental material are fused magnesia-alumina spinel, high purity fused magnesite, light burned bauxite in dengfeng and a small amount of sintering aids.Mixed raw materials evenly, pressed into strips, put the samples in the high temperature nitriding furnace.Selected two series of test antioxidation experiment samples, one series were powder samples, the other series were block samples.Measured the oxidation weight gain rate, TG-DTA curves, the apparent characteristics of the oxidized samples and the physical properties of the samples before and after oxidation.The results show that prepared by the same process conditions the oxidation resistance of MgAlON composite spinel composite is better than that of MgAlON combined with MgO composite.With the same aggregate, the oxidation resistance of the composite materials, bauxite based MgAlON composite is better than alumina based MgAlON composite, after isothermal oxidation, the mechanical properties at room temperature of MgAlON composites are not significantly decreased.

High-temperature Damage of Recycled Aggregate Concrete

ZHANG Wang-chun;WANG Jian-ping

2017, 36(5):  1760-1765. 

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The effect of RA(Recycled Aggregate) replacement ratio on the properties of RAC(Recycled Aggregate Concrete) was studied, including skin morphology, compressive strength and mass pore structure.The results show that there is a thick distribution of cracks or even aggregate spalling, when it is exposed to high-temperature, due to the texture of RA worse than NA, which stems from construction waste.It is observed that both the residual compressive strength and mass of the concrete are significantly remained, after exposure to 400 ℃ within the replacement ratio of 40% RA.However, the elevated temperature exceeds 600 ℃ is helpful in increasing predominately porosity and reducing the relative content of the micropore.

Preperation of Composite Slag Sulphoaluminate Cement Clinker from Electrolytic Manganese-Magnesium

ZHAO Shi-zhen;HAN Feng-lan;WANG Ya-guang

2017, 36(5):  1766-1772. 

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The chemical and mineral composition, physical and chemical properties of electrolytic manganese slag and magnesium slag were first analyzed by chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TG-DSC), respectively.Based on the analysis results, the formulas of sulphoalu minate cement clinker were rational designed using the two types of slag as part of raw materials.Then the effect of sintering temperature on the properties of the clinker was investigated.After adding gypsum into the clinker, the early strength, rapid hardening sulphoalu minate cement was formed.During the heat of hydration, the effect of gypsum content on the compressive and flexural strength of the cement were examined, and the optimum gypsum dosage can be determined.The experimental results show that the electrolytic manganese slag and magnesium slag can be used as valuable raw material for preparation of sulphoalu minate cement clinker.With the two slags of 21% and 21%, respectively, the composition of sintered clinker are mainly C2S and C4A3S-after being treated at 1260 ℃ for 30 min.The optimal mechanically properties of the prepared cement are achieved with 28 d flexural strength of 5.1 MPa and compressive strength of 31.2 MPa when 15% gypsum is added in the clinker.The impermeability grade reaches P6, and the clinker and hydration product can solidify the heavy metal effectively, which can not be leached easily.

Development and Application of High Strength Iron Runner

YANG Qiang;LI De-min;JIANG Le;WANG Zi-jun;ZUO Xiao-yang

2017, 36(5):  1773-1776. 

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The lower high temperature performance of Al2O3-SiC-C castables for blast furnace trough is mainly related to the additions of cement and microsilica powder.The effect of microsilica powder and cement content on the strength of the castables was investigated using brown corundum, silicon carbide as main raw materials.The results show that using high alumina 80 cement instead of the original 70 cement and reducing the addition amount,could improve the hot modulus of rupture significantly without decreasing the coldstrength due to the formation of the well-developedmullite crystal.The technology was applied to a blast furnace of 1080 m3 capacity.The iron influx was increased by 38 thousand tons and a good effect was achieved.

Mechanical Properties of RPC Containing Basalt Fiber

JU Yan-zhong;FAN Yun-ting;WANG De-hong;BAI Jun-feng;WEI Chun-ming

2017, 36(5):  1777-1782. 

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In order to research the effect of basalt fiber in reactive powder concrete, the splitting tensile strength test and the cube compressive strength test of basalt fiber reinforced reactive powder concrete with the parameters like the content of the fiber, the length of fiber, the water-binder ratio of reactive powder concrete and the age of the concrete were conducted.The results show that for the reactive powder concrete mixed with basalt fiber whose length is 12 mm, the best water-binder ratio is 0.22 and the best volume content is 0.10%, and the splitting tensile strength improves 38.53% compared to the reactive powder concrete without fiber.For the reactive powder concrete mixed with basalt fiber whose length is 6 mm, the best volume content is 0.05%, and the splitting tensile strength improves 27.16% compared to the reactive powder concrete without fiber.

Maturity of Early Strength of Concrete Slab

WANG Tie;WANG Xian-li

2017, 36(5):  1783-1789. 

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The 35 cm thick chunks of concrete slab was designed and tested on two different conservation of the environment, and the temperature and humidity within the concrete curing version were measured.In addition, the different shapes of concrete the inner member porosity humidity prediction mode were established, to explore the interior version with the cylinder test humidity of differences, to find differences in the relationship between the humidity and the compressive strength of the test, in order to establish a more generalized theory of maturity.

Experimental Study on Influences of Sulfate-resistant and Corrosion-inhibitingAdmixtures on the Performance of Concrete

CHEN Bei;LI Xiang;ZHANG Xing-shi

2017, 36(5):  1790-1795. 

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Different percentages of sulfate-resistant and corrosion-inhibiting admixtures take the place of Portland cement equivalently to compound concrete and study the influence of concrete compression strength, sulfate attack coefficient, chloride penetration coefficient, electric quantity and other index and observe morphology of cement hydration product of concrete 3 d, 7 d, 28 d by SEM.The results show that after infusion of sulfate-resistant and corrosion-inhibiting admixtures, working performance, later mechanics performance, sulfate corrosion resistance performance, chloride penetration performance, and chlorine salt corrosion resistance performance are superior to normal concrete obviously;infusion of sulfate-resistant and corrosion-inhibiting admixtures can consume C3A and Ca(OH)2 produced by cement hydration and generate ettringite and C-S-H gel and produce micro-expansion effect, which makes the structure more compact and improves the performance of sulfate and chlorine salt corrosion resistance.

Characteristics of Hydration Products and Pore Structure of Low Clinker Slag Cement Based on Different Size Distribution

WEI Ying

2017, 36(5):  1796-1800. 

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Low clinker slag cement (LSC) is a hydraulic cementitious material which consist mainly of granulated blastfurnace slag, calcium sulphateand sometimes contain a little additional constituents and low amount of cement clinker.The purpose of this paper was investigating the influence of cement fineness on the hydration process and microstructural, mechanical and physical properties of LSC paste.The compressive strength, heat of hydration and electrical resistivity, hydration product and pore structure, were studied on the LSC pastes with specific surface area of 358 m2/kg, 450 m2/kg and 516 m2/kg, respectively.The results show that the compressive strength of LSC paste can be improved by increasing the cement fineness from 358 m2/kg to 450 m2/kg.But the strength can not be obviously improved when the cement fineness was further increased from 450 m2/kg to 516 m2/kg.The main hydration products are ettringite and hydrated calcium silicate.Both of heat release rate and electrical resistivity were accelerated when the cement fineness was increased.This indicates that the hydration rate of LSC paste was improved with the increase of cement fineness.The volume fraction of gel pore was increased with the increase of cement fineness for the hardened LSC pastes.

Influence of Different Silicon Source and Phosphoric Source on the Structure and Morphology of Small Gain SAPO-34 Molecular Sieves

GUO Hong;ZHAO Zeng-dian;GAO Xiao-liang;LI Wen-xiu;LIANG Rong-hai

2017, 36(5):  1801-1805. 

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The small gain SAPO-34 molecular sieves were prepared by hydrothermal synthesis method.The effects of different silicon source (silica sol, SiO2 nano powder, ethyl silicate) and phosphoric source (Phosphoric acid, poly phosphoric acid)on SAPO-34 formation were investigated.The results indicate that performance of nano-sized SiO2 powder is better than TEOS (tetraethoxysilane) and silica sol, the product prepared by nano-sized SiO2 powder has the high degree of crystallinity, the standard cubic structure with crystals size of about 300 nm under the condition of the initial gel mole ratio of 1.0 Al2O3∶2.0 P2O5∶0.6 SiO2∶4.0 TEAOH∶105.0 H2O with the crystallization temperature of 180 ℃ and the crystallization time of 48 h;when the poly phosphoric acid instead of phosphoric acid as the phosphoric source, the cubic crystals structure changed to flaky morphology and the crystals size increased to about 500 nm.

Effect of Magnetic Field Treatment on Viscosity and Surface Tension of PFS Solution

LIU Dan-ni;YAN Ke-jun

2017, 36(5):  1806-1810. 

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In order to enhance the PFS (PFS) solution solubility, improve the effect of coagulation water treatment in PFS solution under different magnetic parameters of viscosity and surface tension were determined by experiment.The memory effect of PFS variation of solution viscosity and surface tension and magnetic field on PFS solution of different magnetic parameter was studied.The experimental results show that the viscosity and surface tension of PFS solution decrease with the increase of magnetic field intensity and magnetization time, and the effect of magnetic field on solution has a certain memory effect, about 10 h.In the alternating magnetic field, reduce the entropy of PFS solution, increase the hydrogen bonding interaction after magnetization liquid more ordered.