自密實混凝土的發(fā)展、應(yīng)用與調(diào)查 土木工程專業(yè)畢業(yè)設(shè)計外文翻譯-中英文對照.doc

濟(jì)南大學(xué)畢業(yè)設(shè)計外文資料翻譯畢業(yè)設(shè)計外文資料翻譯題 目 自密實混凝土的發(fā)展、應(yīng)用與調(diào)查學(xué) 院 土木建筑學(xué)院 專 業(yè) 土木工程 班 級 學(xué) 生 學(xué) 號 指導(dǎo)教師 二一 年 月 日- 15 -Journal of Advanced Concrete Technology Vol. 1, No. 1, 5-15, April 2003 / CoSELF-COMPACTINGCONCRETEDEVELOPMENT,APPLICATIONSANDINVESTIGATIONSMasahiro OUCHIAssistant Professor, Dr. Eng.Kochi University of TechnologyTosa-yamada, Kochi, 782-8502 JAPANm-ouchiinfra.kochi-tech.ac.jpJournal of Advanced Concrete Technology Vol. 1, No. 1, 5-15, April 2003 / CoSELF-COMPACTINGCONCRETEDEVELOPMENT,APPLICATIONSANDINVESTIGATIONSMasahiro OUCHIAssistant Professor, Dr. Eng.Kochi University of TechnologyTosa-yamada, Kochi, 782-8502 JAPANm-ouchiinfra.kochi-tech.ac.jpABSTRACTSince the development of self-compacting concrete in 1988, the concrete has been used in practical structures in Japan. Investigations have been carried out from the viewpoint of making it a standard concrete. Recommendations and manuals for self-compacting concrete were also established.Key words: self-compacting concrete, development, application,Investigation1. DEVELOPMENT OF SELF-COMPACTING CONCRETEFor several years beginning in 1983, the problem of the durability of concrete structures was amajor topic of interest in Japan. To make durable concrete structures, sufficient compaction byskilled workers is required. However, the gradual reduction in the number of skilled workers inJapans construction industry has led to a similar reduction in the quality of construction work.One solution for the achievement of durable concrete structures independent of the quality ofconstruction work is the employment of self-compacting concrete, which can be compacted intoevery corner of a formwork, purely by means of its own weight and without the need forvibrating compaction. The necessity of this type of concrete was proposed by Okamura in 1986.Studies to develop self-compacting concrete, including a fundamental study on the workabilityof concrete, were carried out by Ozawa and Maekawa at the University of Tokyo 1.The prototype of self-compacting concrete was first completed in 1988 using materials alreadyon the market. The prototype performed satisfactorily with regard to drying and hardeningshrinkage, heat of hydration, denseness after hardening, and other properties. This concrete wasnamed “High Performance Concrete.” and was defined as follows at the three stages of concrete:(1) fresh: self-compactable(2) early age: avoidance of initial defects(3) hardened: protection against external factorsAt almost the same time, “High Performance Concrete” was defined as a concrete with highdurability due to low water-cement ratio by Professor Aitcin. Since then, the term highperformance concrete has been used around the world to refer to high durability concrete.Therefore, Okamura has changed the term for the proposed concrete to “Self-Compacting HighPerformance Concrete.”2. APPLICATIONS OF SELF-COMPACTING CONCRETESince the development of the prototype of self-compacting concrete in 1988, the use of self-compacting concrete in actual structures has gradually increased. The main reasons for theemployment of self-compacting concrete can be summarized as follows:(1) to shorten construction period(2) to assure compaction in the structure:especially in confined zones where vibratingcompaction is difficult(3) to eliminate noise due to vibration: effective especially at concrete products plantsThat means the current condition of self-compacting concrete is a “special concrete” rather than standard concrete. Currently, the percentage of self-compacting concrete in annual product of ready-mixed concrete in Japan is around 0.1% (Fig. 1) 2.A typical application example of Self-compacting concrete is the two anchorages of Akashi-Kaikyo (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 self-compacting concrete, was introduced for this.The concrete was mixed at the batcher plantbeside the site, and was the pumped out of theplant. It was transported 200 meters throughpipes 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 self-compacting concrete shortened the anchorage construction period by 20%, from 2.5 to 2 years. Self-compacting concrete was used for the wall of a large LNG tank belonging to the Osaka GasCompany, whose concrete casting was completed in June 1998 3. The volume of the self-compacting concrete used in the tank amounted to 12,000 m3. The adoption of self-compacting concrete means that (1) the number of lots decreases from 14 to 10, as the height of one lot of concrete castingwas 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.Self-compacting concrete is often employed in concrete products to eliminate the noise ofvibration 3. This improves the working environment at plants and makes it possible for concrete product plants to be located in the urban area. The annual production of concreteproducts using self-compacting concrete exceeded 200,000 tons in 1996 2.3. INVESTIGATIONS ON SELF-COMPACTING CONCRETEVarious investigations have been carried out in order to make self-compacting concrete astandard one. The items to be solved are summarized as follows:(1) self-compactability testing method(2) mix-design method including evaluation method for materials(3) construction method including acceptance test at jobsite(4) new construction system to make full use of the performance of SCCThe investigations were carried out at each university, large construction company and material maker.Committee activities were also carried out. As the result, Architectural Institute of Japan and Japan Society of Civil Engineers established “Recommendations for Mix Design and Construction Practice of Highly Fluidity Concrete” in 1997 and “Recommendation for Construction of Self-Compacting Concrete” in 1998 respectively. The national ready-mixed concrete industry association, Japan, established “Manual for Manufacturing of Self-Compacting Concrete” in 1998 3.3.1 Self-compactability testing methodThere are two purposes for self-compactability testing methods. One is to judge whether theconcrete is self-compacatable or not, and the other is to evaluate deformability or viscosity forestimating proper mix-proportioning if the concrete does not have sufficient self-compactability.Of the many testing methods proposed for evaluating self-compactability, the U-type test proposed by the Taisei group is, at this stage,the most appropriate (Fig. 3) 4. In this test,the degree of compactability can be indicated by the height that the concrete reaches afterflowing through an obstacle. Concrete with the filling height of over 300 mm can be judged as self-compacting.A modification method for mix-proportion incase of insufficient self-compactability was also proposed, in which flow and funnel tests are used for estimating proper water-powder ratio and superplasticizer dosage by evaluating the deformability and viscosity of mortar in concrete 3.3.2 Mix-design methodSelf-compactability can be largely affected by the characteristics of materials and the mix-proportion. A rational mix-design method for self-compacting concrete using a variety ofmaterials is necessary. Okamura and Ozawa have proposed a simple mix-proportioning systemassuming general supply from ready-mixed concrete plants 4. The coarse and fine aggregatecontents are fixed so that self-compactability can be achieved easily by adjusting the water-powder ratio and superplasticizer dosage only.3.3 Evaluation method for materialsInvestigations on establishing evaluation method of materials, especially powder materials andsuperplasticizer have been carried out from the viewpoint of establishing a rational mix-proportioning method, that is, especially adjusting method for water-powder ratio andsuperplasticizer dosage, and of developing suitable material for self-compacting concrete.Ouchi et. al proposed evaluation method for the effect of superplasticizer and water independentof each other on the flowability of mortar by using flow and funnel tests 3.Some general construction companies employ a segregation-inhibiting agent so that the self-compactablity can be kept constant independent of the variation of unit water content, especiallydue to the variation of surface water content in the sand. There are various agents proposed andavailable in Japan. The evaluation method for the effect was also proposed 3.3.4 Acceptance test at jobsiteSince the degree of compaction in a structure mainly depends on the self-compactability of concrete and poor self-compactability cannot be compensated by the construction work, self-compactability must be checked for the whole amount of concrete just before casting at the jobsite.However, conventional testing methods for self-compactability require sampling and this can be extremely laborious if the self-compactability acceptance test is to be carried out for the whole amount of the concrete. A suitable acceptance test method for self-compactability has been developed by Ouchi et. al 3:(1) The testing apparatus is installed between agitator truck and pump at the job site. Thewhole amount of the concrete is poured into the apparatus.(2) If the concrete flows through the apparatus, the concrete is considered as self-compactable for the structure. If the concrete is stopped by the apparatus, the concrete isconsidered as having insufficient self-compactability and mix-proportion has to be adjusted.This apparatus was successfully used at the construction site of the Osaka Gas LNG tank, andsaved a considerable amount of acceptance test work (Fig. 4) 3.3.5 New structural design and construction systemsBy employing self-compacting concrete, the cost of vibrating compaction can be saved and thecompaction of the concrete in the structure can be assured. However, the total cost for theconstruction cannot always be reduced, except in large scale constructions. This is because theconventional construction system is strongly based on the necessity of the vibrating compactionof concrete. Self-compacting concrete can greatly improve construction systems previouslybased on conventional concrete requiring vibrating compaction. This sort of compaction, whichcan easily cause segregation, has been an obstacle to the rationalization of construction work.Once this obstacle has been eliminated, concrete construction can be rationalized and a newconstruction system, including formwork, reinforcement, support and structural design, can bedeveloped (Fig. 5).One example of this is the so-called sandwich-structure, where concrete is filled into a steelshell. This sort of structure has already been completed in Kobe, which could not have beenachieved without the development of self-compacting concrete (Fig. 6)3.4. CONCLUSIONSIt is considered that the main obstacles for making self-compacting concrete widely used havebeen solved. The next task in Japan is to distribute the technique for manufacturing andconstruction of self-compacting concrete rapidly. In addition, new structural design andconstruction systems making full performance of self-compacting concrete should beintroduced.REFERENCES1 Ozawa K, et. al. Development of high performance concrete based on the durability designof concrete structures: Proceedings of the second East-Asia and Pacific Conference onStructural Engineering and Construction (EASEC-2), Vol. 1, pp. 445-450, January 1989.2 Kodama, Y. Current condition of self-compacting concrete (written in Japanese), CementShimbun, No. 2304, Dec 1997.3 Ozawa K (editor), et. al. Proceedings of the International Workshop on Self-CompactingConcrete (CD-ROM), Kochi, Japan, March 1999, including state-of-the art report on self-compactability evaluation, materials & design, construction, manufacturing & concreteproducts and summary of recommendations & manuals for self-compacting concrete in Japan.Also available from Concrete Engineering Series, No. 30, Japan Society of Civil Engineers,March 1999. http:/www.infra.kochi-tech.ac.jp/scc-net/4 Hayakawa M, et. al. Development & application of super workable concrete, RILEMInternational Workshop on Special Concretes: Workability and Mixing, Paisley, 1993.5 Okamura H, et. al. Mix-design for self-compacting concrete, Concrete Library of JSCE, No.25, pp.107-120, June 1995.Civil Engineers London 1999 Session pp. 53 - 54.自密實混凝土的發(fā)展、應(yīng)用與調(diào)查正弘藕池高知大學(xué)摘要 自1988年以來，自密實混凝土在日本獲得了很快發(fā)展，并已經(jīng)廣泛應(yīng)用于實際結(jié)構(gòu)中。為了制定自密實混凝土制作方面的標(biāo)準(zhǔn)而進(jìn)行了調(diào)查。自密實混凝土的使用建議和手冊也已經(jīng)建立。關(guān)鍵詞 自密實混凝土、開發(fā)、應(yīng)用、調(diào)查.自密實混凝土的發(fā)展從1983年開始的幾年中，混凝土的耐久性問題在日本是一個重要的課題。為了使混凝土結(jié)構(gòu)充分壓實需要大量的技術(shù)工人。然而，技術(shù)工人的數(shù)量在逐漸減少，從而導(dǎo)致了日本建筑行業(yè)的工程質(zhì)量相應(yīng)的下降。為了解決這一問題，岡村寧次在1986年提出了一個解決方案，采用自密實混凝土這一技術(shù)。該技術(shù)是僅依靠混凝土的自重是混凝土壓縮成型而不需要振動壓實。為了發(fā)展自密實混凝土這一技術(shù)，東京大學(xué)的小澤一郎和前川進(jìn)行了一個可行性的基本研究。自密實混凝土與1988年首次應(yīng)用于實際建設(shè)中。并且，自密實混凝土干燥后的收縮率、水硬性和密實度及其他屬性等指標(biāo)都令人滿意。因此，這種混凝土也被稱為“高性能混凝土”，并具有一下三個特點（1）新特性：自密實性（2）早期齡期：沒有初始缺陷（3）硬化：不受外部因素干擾幾乎在同一時間，?？松淌诎选案咝阅芑炷痢倍x為一種水灰比很低而耐久性很好的混凝土。從那時起，高性能混凝土在世界各地廣泛應(yīng)用，特指這種高耐久性混凝土。因此，岡村改變了最初的名稱，而改稱這個課題為“自密實高性能混凝土”。2.自密實混凝土的應(yīng)用由于自密實混凝土自1988年以來的發(fā)展，自密實混凝土在實際結(jié)構(gòu)中的使用已經(jīng)逐漸發(fā)展。自密實混凝土的大力發(fā)展原因可以概括如下：（1）縮短了施工工期（2）可以保證結(jié)構(gòu)的密實性。尤其是在不便于采用振動施工操作的密閉區(qū)域。（3）不會產(chǎn)生振動噪音，尤其是在混凝土制品廠效果明顯。這意味著自密實混凝的目前狀況是一種“特殊混凝土”,而不是普通意義上的混凝土。目前，在日本自密實混凝土占每年準(zhǔn)備預(yù)攪拌混凝土的0.1%左右。（如圖1）。圖1.日本每年生產(chǎn)的自密實混凝土總量1997年日本預(yù)拌混凝土總量是167,6201,000一個關(guān)于自密實混凝土應(yīng)用的典型實例是建成于1988年4月具有兩個泊位的明石海峽大橋。它是世界上跨度最大的大橋（1991米）。大橋的兩個錨地耗費的混凝土量達(dá)290,000立方米。為了應(yīng)用自密實混凝土而建立了一個新的系統(tǒng)?；炷猎诨炷凉S攪拌并在現(xiàn)場泵送?；炷帘撑帕谐砷g距3到5米的管道泵送到200米以外的澆筑現(xiàn)場。混凝土被從間隔5米的管道向外澆筑。這種泵送管道的閥門可以自動控制，使混凝土的表面可以維持平整。后來的分析表明使用自密實混凝土使錨地的施工工期縮短了20%，從2.5年縮短到2年。（圖2）圖2明石海峽大橋的4A錨地自密實混凝土首次應(yīng)用于墻體工程是在屬于大阪煤氣公司的一個大型液化天燃?xì)鈨Υ婀奚?，該工程澆筑完成?998年6月。這個罐體耗用的自密實混凝土量達(dá)12000立方米。自密實混凝土的應(yīng)用意味著：（1）混凝土攪拌站的數(shù)量隨著澆筑高度的增加從14個減少到10個。（2）攪拌混凝土工人的數(shù)量由150個減少到50個。（3）結(jié)構(gòu)的建設(shè)工期從22個月下降到18個月?；炷林破反蠖嗖捎米悦軐嵓夹g(shù)以減少振動噪音。這也提高了混凝土制品廠的工作環(huán)境，并使混凝土制品廠在市區(qū)生產(chǎn)成為了可能。在1996年自密實混凝土的使用量超過了20萬噸。3.自密實混凝土的調(diào)查為了制定自密實混凝土的標(biāo)準(zhǔn)一，已經(jīng)進(jìn)行了廣泛的調(diào)查。要解決的項目概括如下:（1）自密實試驗方法（2）組合設(shè)計方法，包括材料的評價方法（3）施工方法，包括在現(xiàn)場的驗收試驗（4）充分利用自密實混凝土的新的建筑體系這項調(diào)查在每所大學(xué)、大型建筑公司和材料制造商進(jìn)行，委員會也進(jìn)行了活動。作為結(jié)果，日本建筑學(xué)會和土木工程師學(xué)會分別于1997年推出了“高流動性混凝土配合比設(shè)計和施工的建