土木中外文翻译

On TheApplication of High-Performanee ConcreteSummary The high-performa nee con crete is a main direct ion of the tech ni cal developme nt of recentconcrete, the foreign scholar has called that the concrete in 21st century. Norway carried on research to this at first in 1986, n amed formally from America n Nati onal Stan dard, tech no logical research in stitute (NIST)and a seminar hosted together of American Concrete Institute (ACI) in 1990. Conference stipulate high- performa nee con crete to have whom some performa nee require homoge nize the con crete, must adopt thestrict con struct ion craft, adopt high-quality material formulate, easy to water smash, ema nate, mecha nics performanee steady, early intensity high, with performanee such as toughness and volume stability durable concrete, especially suitable for the skyscraper, bridge and open to the building structure of the harsh environment.Key words con crete; performa nce;e ngin eeri ng;applicatio n1.In troducti onRece nt high-performa nee con crete is the main directi on of the developme nt of con crete tech no logy, foreig n scholars have called the 21st een tury con crete. Norway in 1986, this was the first study in 1990 by the Natio nal In stitute of Sta ndardsa nd Tech no logy (NIST) and the American Concrete Institute (ACI) at a seminar co-hosted a formal naming. The General Assembly for high-performanee concrete is a certain performanee requirements of the uniform quality of con crete, it must adopt a strict con struct ion tech no logy, using high-quality materials, preparation, ease of pouring pound, non-segregation, mechanical properties and stability, high early strength with toughness and size stability durability performanee of concrete, especially for high-rise buildings, bridges, and exposure to harsh environments in architectural structures. As an integrated high-performanee concretewith excellent technical characteristics of materials at home and abroad has aroused world wide attention with the engineering and concern. 10 years, the world, many countries have invested a great deal of man power, finan cial and material resources to con duct the research and developme nt applicati ons, to en able high-performa ncec on crete tech no logy has made great progress in the selection of raw materials, mix design, physical and mechanical properties of , durability, workability, structure and performa nee as well as applicati on of tech no logy have made both theoretical basis an dits practical value of scie ntific and tech no logical achieveme nts.In 1993, the technical committee under American Concrete Institute proposed a new high- performa nceconcrete was defined: Meet project special various performanceof requirement, but in cludi ng easy to water, smash in stead of ema nat ing, high Ion g-term mecha nics performa nce,high early in ten sity, high and tough an d ten sile and high volume stability, or the service life in the harsh environment is for a long time, and homogenizing good concrete. In recent years, American Concrete Institute provides more concise definition on a piece of characters again: "The high-performanee concrete is that one kind can accord with special performanceand synthesize the concretewith the homogeneity requirement,the concretecan get with regular con crete comp onen t material and com mon mixing, habit method smashed and maintained to water often. "High-performanee concrete, it is used for signifying the concrete with high work degree, high strength andhigh durability beginning. This kind of concretemust be designedand possessechigh volume stability.For reduce con crete shri nk and do fracture produced to con tract with temperature,must limit the grout content in the concrete mixture. The high-performanee concrete amount of total grout limited of design method of match ratio that Mehta and Actcin put forward is 1/3 of the concrete volume; Allow some silicate cementspend volcanic ash or have glue person who congeal to mix, shut material replace. AcTcin has been prophesied: Mix slay, fly ash, silica flour, inferior clay, the rice husks dust and three yuan of the lime stone powder and mix cement besidescan make the preparation of the high-performanee concrete more economic ing, still can give play to exceedinga pile of function of them, improve its property while mixing an dharde ningn ewly.2.High performanee concrete in modern engineeringHigh performa neee on crete tech no logy is successfully used in many parts of the world of offshore structures and grew up across the bridge eon struct ion, Lan gley, who described growing up across a few bridges in Canadawith the workability.They are used in the girder, mound departmentand moundbase,it is 450 Kg/m3 that silica flour mix cement consumption, water 153L/ m3, guide angry pharmaceutical 160mL/ m3 and high-efficient water-reducing agent 3L/ m3. Its slump is probably in 200mm; Includes 6.1% of toleranee; 1d, 3d, 28d compression strength are 35, 52 and 82 MPa respectively; The foundation and other big mixed cement eonsumption of pieces of eoncrete are 307 Kg/m3, fly ash 133 Kg/m3, water eonsumption is close, but guide the angry pharmaceuticaland mixing amount of high-efficient water-reduci ng age nt to reduceby a large margi n, make an appo in tme nt in 185mm in slump; In eludes 7% of tolera nee; 1d, 3d, 28d and 90d compressio nstre ngth are 10, 20, 50 and 76 MPa respectively. And water permeability of U.S.A. and chlorine ion fast to permeate standard method experimental result indicate according to Canada: Both part of eoncretes prese nt very low permeability. To high-performa nee eon crete eon struct ion of structure, n eed, put emphasis on, stre ngthe non-the-spot laboratorytest and in spectionof quality very much.Another area of development of high performanee eoncrete is a high performanee lightweight eoncrete,as opposed tosteel,ordinary eoncretestrength/ weight ratio is very low, mixed with high-strength concretesuperplasticizer is significantly enhancedthe ratio; with a large number of tiny holes lightweight aggregateto replace part of the normal aggregate, will be able to further improve this ratio. As the aggregatequality of different density of 2000 Kg/m3, compressive strength at 70 ~ 80 MPa high-performanee lightweight concrete in a nu mber of coun tries have already commercialized and used in comp onent product ion. In Australia, Canada, Japan, Norway and the United States, high-performanee lightweight concretehas been used in fixed and floating drilling platform; becauseof mud and water, the in terface betwee n the aggregateb ond stre ngth, it can be impermeable, so the erosi on of the en vir onmen table is very durable.-Doped silica powder 10 ~ 15% or even higher superplasticizer prepared mixture of cement concrete,with excellent adhesion, so the spray applied to the wet spraying the structural repair of concrete, whichis one of the areas of high performanee concrete applicati ons.2.1High-performanee concretein high-rise building application s. High- performa ncec oncrete(> 40MPa) over the first 30-story high-rise build ings used for reinforced concrete structures, because such buildings in the lower third of the columns, using ordinary con crete whe n the great cross-sect ion. In additi on to sav ings in material costs, as compared with the steel structure, speeding up the adoption of concrete structures is an important feature, since the United States in Chicago in 1965 with 50 MPa concretepouring Lake Point Tower some of the pillars has been everywhere in North America and other countries using high-performanee concrete to build high-rise building. Chicago 79-story Water Tower Place building columns using 60MPa eoncrete; Toronto's Scotia PlazaBuilding and Seattle's Two union Square Building 2 Buildings then 90 and 120MPa respectively intensity of high-performanceconcretepillars.Application examples: a. high-performanceconcrete application of C80 high-strength and high-performanceconcretein Shenyang FangyuanBuilding, Onishi Electric Park, and many other high-rise building in the application of eoncretefilled steel tubular columns.b.Shanghai Researchin the field of high performanceconcrete in a large number of promising results obtained, of which representative results are: China's tallest building - 88 C40 floor Jinmao Tower once pumped to 382.5m; Tomorrow Square slag pumping C80 eon crete; in Shan ghaieducati onTV stati on based on complex buildi ng masse on crete, ceme nt consumption accountedfor only 46% of the total cementitious materials, preparation of the full amount of c on creteslurry, eon cretework, cohesive nessa nd resista nee to segregati onare very excelle nt performa nce,stre ngth ofC40 high-performa ncec on crete.2.2High-performanee pavement concretea.High-performanee pavement concrete significanee of the studyWith the increasing traffic and transport requirementsto develop the "long-life low- maintenan ceroad,"With high-performa nee paveme ntcon crete, to improve the flexural stre ngth and durability of concreteis the currenttrend of development of concretepavement.b.Overseas developme ntsHeld in 1997 at the XVI International Conferenceon Concrete Pavement,pavement desig n proposed notonly to raise the average i nten sity of dema nd, but also make the durability requireme nts.Made in the direct ion of future developme ntof ultra-high ten sile strength up to 17MPa strength concrete, for paving continuous concrete pavement. Improve the concrete pavement surface compactness and impermeability are very important, and this is through high-performanee concreteto achieve.c.High-performanee pavement eoncrete strengthHigh-performanee eoncrete pavement important feature is a high flexural strength. Using high-performancepavementconcretecan significantly improve the bearing capacity of pavement, extend service life, or thinning the thickness of pavement to reduce the project cost.d.High-performanee durability of concrete pavementHigh-performa nee eon crete paveme ntma in feature is a sufficie nt durability, resista nt to climatic and environmental effects of Iong-term damage to ensure that the design of pavementandwithin the eoncretecan work properly.e.High deformation characteristics of eoncrete pavement(1)Shri nkageRoad panel surface area of great evaporati on, shri nkage may be caused by Tao panel surfaceof shrinkage cracks,the needto increaseconservation.(2)The flexural modulus of elasticityHigh-performancepavementconcreteflexural elastic modulus E, by measurement,one for 4.305104Mpa, 2 grade 4.845104Mpa, 3 grade 4.605104Mpa. Intensity of three high- performa nee pavement eoncrete mix, the aggregate amount of less coarse aggregate maximum particle diameteris smaller.f.The application ofApplicati on of high-performa ncepaveme ntcon creteyield sig nifica nt ben efits:(1)increasepavement strength;(2)extend the pavementservice life;(3)reducing the project cost;g.Applicati ons(1) in the U.S. about 70% of the road pavementusing high-performanceconcrete: one in North Dakota, 1988 and 1989 in the summer, with 20000m3 of concrete paving thickness of 200 mm of the surface, its water-cementratio of 0.43, cement consumption 100 Kg/m3, fly ash 220 Kg/m3; the road Texas dem on strati on project has successfully adopted this new material.(2) The Qin ghai-Tibet railway con struct ion project fully promote the use ofh.Con clusi onThree intensity levels of high-performance pavement concreteis extremely good quality, cost of materials basically does not in crease or in creased margi nally, for the differe nt requirements of the project choose to use, the construction of low-maintenance Iong-life paveme nt, road, its social, econo mic ben efits are eno rmous, and worth promot ing and continued research to promote the country's airports cement concrete pavementconstruction and road paveme ntengin eeri ng is en teri ng a new stage of developme nt to meet the grow ing demandfor aviation and transportationneeds.2.3Marine Concrete Structures - Durability of hydraulic structures to enhance port study and propose tech ni cal and econo mic rati on al, easy to promote the use of a new marine engin eeri ng high-performa nce con creteSpan bridges, undersea tunnels and offshore oil platforms, is an instance of this applicati on.Such as: a, Shantou, Hong Kong outside the Deepwater Channel Regulation Project; b Lingdingyang Pearl River Estuary DeepwaterChannel Regulation Project;c,Qin gdao, Nin gbo Beil un and other ports that can berth 200,000-t on class built tan kers an dore shipsdeep-waterberths2.4Free Vibration of Self-compacting ConcreteDue to vibrati on-free self-compacti ng con crete has a very good work,maki ng the con crete filling, compactness,uniformity has been significantly improved, becoming a new concrete tech no logy, progressis listed asa family of high performa ncec on crete.Vibrati on-free self-compact ing con creteis the first study from Japa no ver the last decade to develop and put into a moder n con crete e ngin eeri ng tech no logy. Since vibratio n-free selfcompact ing concrete in engineering applications can be made to improve concrete quality, improve con cretec on structi on operatio ns, to support the con struct ion no ise and improve labor productivity, speedup the con struct ion cost reducti on and other tech nical and econo mic effect, in recent years have given the world great pay attention to. Japan is expectedby 2003 there will be 1 / 2 works with the free vibration ofconcreteself-compacting concretepouring.As the namesuggests, vibration-free self-compacting concrete is poured concrete, when self-gravity alone without any external force tamping to achieve self-compacting, selfleveling of a concrete. Vibration-free Self-compacting concrete should have three characteristics:⑴ Mobility;(2)Good stability - does notdisintegrate;(3)Reinforcement and templates in any gap, with a good through capacity, does not produceblock ing.Accord ing to the requireme ntsof these three characteristics, vibrati on-free preparati on of self-compactingconcrete principles and methodssectionare asfollows:Fresh concretephase is a particle suspendedsolids, the continuous medium is a cement paste, which is liquid and Concrete Aggregates, comparedwith solid-phase. All the particles in suspension, mobility and particle balancebetweensegregationis necessary. Free vibration of fresh self-compacting concrete in the absence of external force to be real concrete formwork to give full fill all the gaps and achieve the compact, more importantly, to both good fluidity and stability.In order to obtain high mobility, we must first reduce the friction between the particles. Incorporation of superplasticizer to reduce the surface tension of particles of course is necessary, but vibration-free performance requirements of self-compacting of view, alone doped superplasticizer was also difficult to achieve, needs to mixed with a certain amount of ultra-fine material.To obtain good stability, so that materials are not disintegrate, the liquid must have the appropriate rheology, can not produce bleed ing and preve nt particle segregati on. To achieve this request, also be mixed with an appropriate amount of particle size <0.25mm fine filler and in somecasesmixed with viscosity modify ing age nt (tackifier).In order to be able to flow through the reinforcement of concreteand templatesin the gap without creat ing any obstruct ion, in additi on to the desig n of engin eeri ng structures be selected according to the appropriate particle size and morphology of aggregates, the liquid volume is the amount of its rheological properties important parameters. The rheological properties is based on the Bingham rheological model used to evaluate the viscometer, and should havea low yield stress andplastic viscosity appropriate.By rheological point of view, vibration-free matrix of self-compacting concrete is a free flow ofultra-fine paste, the paste is made of cement andcomposedof fine material, the liquid surro unding thesolid particles with the thick ness of the serosal layer in creases with the in crease, while the serosal layer thick ness of solid particles in the paste has beefilled before the gap betweenthe formation, therefore, the thickness of the slurry affects the shapesby solid particles. For the paste, apart from the requirements of high liquidity, the need of sufficient high viscosity, must be a high-viscosity Newtonian fluid, in order to prevent segregati on.Vibrati on-free self-compact ingcon cretepreparati on processas show n.Ceme ntUltra-fine admixture of water superplasticizerJ J JThe free flow of slurry of fine aggregateJJThe free flow of mortar of coarseaggregateJJSelf-compact ing Con creteVibration-free self-compacting concrete mix design, first make sure the gap under the aggregateliquid volume of content needed. The composition of the liquid cement, water, additives, and <0.25mm ultra-fine material. Super fine materials and the total aggregate volume ratio (S / A) is free of vibration of self-compacting concrete mix design in an important parameter.Zhen-ming, the mobility of self-compacting concretewill be with the S / A in creased with the in crease, while the elastic modulus of no sig nifica ntimpact. Basically, according to the required water-cement ratio to determine the compressive strength of concrete. Vibration-free self-compacting concrete due to the rheological behavior of volume and compositi on of the material has a very close relati on ship, therefore, vibratio n-free selfcompact ingconcrete mix design is recommendedratherthan weight ratio of the volume ratio.3.High-performanee concrete in terms of performanee on the remaining problems and to improve the wayPreparati onof high-performa ncec on crete is characterized by low water-ceme ntratio, and mixed with a sufficient number of fine mineral admixtures and superplasticizer, so concrete has excelle nt tech ni cal characteristics of an in tegrated, but this also producedtwo worthy of attention Performancedeficiencies: (1) self-desiccation causedby autogenousshrinkage; (2) brittle.ConclusionResearch and development of high performanee concrete application of traditional concrete major breakthrough in technical performanee, energy conservation, quality, engin eeri ng econo mic, en vir onmen tal and labor protect ion and other aspects of great importanee. It is expected that high performance concrete in engineering applications will rapidly expa nd,a nd achievegreater, more tech nical and econo mic ben efits.浅析高性能混凝土的应用摘要：高性能混凝土是近期混凝土技术发展的主要方向，国外学者曾称之为21世纪混 凝 土。