自密實(shí)混凝土的發(fā)展、應(yīng)用與調(diào)查土木工程專業(yè)畢業(yè)設(shè)計(jì)外文翻譯-中英文對(duì)照(存儲(chǔ)版)
【正文】 by Ozawa and Maekawa at the University of Tokyo [1]. 濟(jì)南大學(xué)畢業(yè)設(shè)計(jì)外文資料翻譯 2 The prototype of selfpacting concrete was first pleted in 1988 using materials already on the market. The prototype performed satisfactorily with regard to drying and hardening shrinkage, heat of hydration, denseness after hardening, and other properties. This concrete was named “High Performance Concrete.” and was defined as follows at the three stages of concrete: (1) fresh: selfpactable (2) early age: avoidance of initial defects (3) hardened: protection against external factors At almost the same time, “High Performance Concrete” was defined as a concrete with high durability due to low watercement ratio by Professor Aitcin. Since then, the term high performance concrete has been used around the world to refer to high durability concrete. Therefore, Okamura has changed the term for the proposed concrete to “SelfCompacting High Performance Concrete.” 2. APPLICATIONS OF SELFCOMPACTING CONCRETE Since the development of the prototype of selfpacting concrete in 1988, the use of self pacting concrete in actual structures has gradually increased. The main reasons for the employment of selfpacting concrete can be summarized as follows: (1) to shorten construction period (2) to assure paction in the structure:especially in confined zones where vibrating paction is difficult (3) to eliminate noise due to vibration: effective especially at concrete products plants That means the current condition of selfpacting concrete is a “special concrete” rather than standard concrete. Currently, the percentage of selfpacting concrete in annual product of readymixed concrete in Japan is around % (Fig. 1) [2]. 濟(jì)南大學(xué)畢業(yè)設(shè)計(jì)外文資料翻譯 3 A typical application example of Selfpacting concrete is the two anchorages of AkashiKaikyo (Straits) Bridge opened in April 1998, a suspension bridge with the longest span in the world (1,991 meters) [3] (Fig. 2). The volume of the cast concrete in the two anchorages amounted to 290,000 m3. A new construction system, whichmakes full use of the performance of selfpacting concrete, was introduced for concrete was mixed at the batcher plant beside the site, and was the pumped out of theplant. It was transported 200 meters through pipes to the casting site, where the pipes were arranged in rows 3 to 5 meters apart. The concrete was cast from gate valves located at 5meter intervals along the pipes. These valves were automatically controlled so that a surface level of the cast concrete could be maintained. In the final analysis, the use of selfpacting concrete shortened the anchorage construction period by 20%, from to 2 years. 濟(jì)南大學(xué)畢業(yè)設(shè)計(jì)外文資料翻譯 4 Selfpacting concrete was used for the wall of a large LNG tank belonging to the Osaka Gas Company, whose concrete casting was pleted in June 1998 [3]. The volume of the selfpacting concrete used in the tank amounted to 12,000 m3. The adoption of selfpacting concrete means that (1) the number of lots decreases from 14 to 10, as the height of one lot of concrete casting was increased. (2) the number of concrete workers was reduced from 150 to 50. (3) the construction period of the structure decreased from 22 months to18 months. Selfpacting concrete is often employed in concrete products to eliminate the noise of vibration [3]. This improves the working env
畢業(yè)設(shè)計(jì)相關(guān)推薦
鄂ICP備17016276號(hào)-1