【正文】 quirement, but including easy to water, smash instead of emanating, high longterm mechanics performance, high early intensity, high and tough and tensile 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 濰坊學(xué)院本科畢業(yè)設(shè)計外文文獻及譯文 2 on a piece of characters again: The highperformance concrete is that one kind can accord with special performance and synthesize the concrete with the homogeneity requirement, the concrete can get with regular concrete ponent material and mon mixing, habit method smashed and maintained to water often. Highperformance concrete, it is used for signifying the concrete with high work degree, high strength and high durability beginning. This kind of concrete must be designed and possessed high volume stability. For reduce concrete shrink and do fracture produced to contract with temperature, must limit the grout content in the concrete mixture. The highperformance 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。 Includes % of tolerance。 The foundation and other big mixed cement consumption of pieces of concrete are 307 Kg/m3, fly ash 133 Kg/m3, water consumption is close, but guide the angry pharmaceutical and mixing amount of highefficient waterreducing agent to reduce by a large margin, make an appointment in 185mm in slump。 1d, 3d, 28d and 90d pression strength are 10, 20, 50 and 76 MPa respectively. And water permeability of . and chlorine ion fast to permeate standard method experimental result indicate according to Canada: Both part of concretes present very low permeability. To highperformance concrete construction of structure, need, put emphasis on, strengthen onthespot laboratory test and inspection of quality very much. Another area of development of high performance concrete is a high performance lightweight concrete, as opposed to steel, ordinary concrete strength / weight ratio is very low, 濰坊學(xué)院本科畢業(yè)設(shè)計外文文獻及譯文 3 mixed with highstrength concrete superplasticizer is significantly enhanced the ratio。 because of mud and water, the interface between the aggregate bond strength, it can be impermeable, so the erosion of the environment able 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, which is one of the areas of high performance concrete applications . Highperformance concrete in highrise building applications. Highperformance concrete ( 40MPa) over the first 30story highrise buildings used for reinforced concrete structures, because such buildings in the lower third of the columns, using ordinary concrete when the great crosssection. In addition to savings in material costs, as pared 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 concrete pouring Lake Point Tower some of the pillars has been everywhere in North America and other countries using highperformance concrete to build highrise building. Chicago 79story Water Tower Place building columns using 60MPa concrete。s Scotia Plaza Building and Seattle39。s tallest building 88 C40 floor Jinmao Tower once pumped to 。 in Shanghai education TV station based on plex building mass concrete, cement consumption accounted for only 46% of the total cementitious materials, preparation of the full amount of concrete slurry, concrete work, cohesiveness and resistance to segregation are very excellent performance, strength of C40 highperformance concrete. 濰坊學(xué)院本科畢業(yè)設(shè)計外文文獻及譯文 4 Highperformance pavement concrete a. Highperformance pavement concrete significance of the study With the increasing traffic and transport requirements to develop the longlife lowmaintenance road, With highperformance pavement concrete, to improve the flexural strength and durability of concrete is the current trend of development of concrete pavement. b. Overseas developments Held in 1997 at the XVI International Conference on Concrete Pavement, pavement design proposed not only to raise the average intensity of demand, but also make the durability requirements. Made in the direction of future development of ultrahigh tensile strength up to 17MPa strength concrete, for paving continuous concrete pavement. Improve the concrete pavement surface pactness and impermeability are very important, and this is through highperformance concrete to achieve. c. Highperformance pavement concrete strength Highperformance concrete pavement important feature is a high flexural strength. Using highperformance paveme