BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:Research in Japan on Ultra High Performance Fibre Reinforced Cemen t-based Composites: Two contributions DTSTART:20171006T121500 DTEND:20171006T131500 DTSTAMP:20261006T132222Z UID:cdfac64d75c86faf9252ce8d672feb54af98690e3777e1639bdfa897 CATEGORIES:Conferences - Seminars DESCRIPTION:Yuji Watanabe\, Senior Research Engineer\, KAJIMA Corporation\ , Tokyo\, Japan\,\n\nDr Tohru Makita\, Structural Engineer\, NEXCO Central \, Nagoya\, Japan  \nApplication of UHPFRC with ettringite generation sys tem for precast member and development of cast-in- situ method presented b y Yuji Watanabe\nUltra High Performance Fibre Reinforced cement-based Comp osites (UHPFRC)\, which typically has a compressive strength of at least 1 50 MPa and tensile strength of at least 5 MPa\, brings a great deal of fle xibility and additional value to design and construction\, including reduc tion in weight and increase of long term durability of members\, through s uch excellent material characteristics as high strength\, high toughness a nd high durability. Especially\, “AFt-UHPFRC\,” an ettringite -generat ing type UHPFRC\, is developed by using Japanese materials and original te chnology. UHPFRC has been used mainly for precast products manufactured in factories equipped with heat curing facilities in order to utilize its hi gh performance. Recently\, mass manufacturing and curing method of precast members assuming the large-scale application   have been established in Japan. However\, depending on the scale of construction and the condition s\, a cast-in-situ method may be more reasonable.\nIn this seminar\, the o bjectives and design by using precast UHPFRC to prestressed concrete bridg e will be introduced with some applications. And reports the results of ex periments and construction aiming at establishing a cast-in-situ method fo r the first time in Japan.\n\nBio : Yuji Watanabe is senior research engin eer of KAJIMA Corporation. He belongs to concrete and construction materia ls group in Kajima Technical Research Institute (KaTRI) since 2006.  He i s one of the development members of AFt-UHPFRC (Japanese version of Ultra High Performance Fibre Reinforced cement-based Composites). And he was res ponsible for the mass production of UHPFRC slab for construction of Tokyo international airport in 2009. He is now engaged in research and developme nt for construction and repair by using high performance concrete.\n\nExpr essway renewal project and upgrading of existing bridge decks using UHPFRC presented by Tohru Makita\nCentral Nippon Expressway Company Limited (NEX CO Central) operates and manages about 2\,000 km expressways in the centra l part of Japan\, 40 % of which have been placed in service for more than 40 years and average in-service period of the expressways is now about 30 years. Recent years have seen growing number of damaged and deteriorated b ridges in the NEXCO Central’s expressways and the number of damaged and deteriorated bridges will get larger in the coming decades. In view of the situation\, extensive renewal project of the expressways was launched in 2015\, in which replacement and upgrading of bridge decks are mainly condu cted.\nIn the expressway renewal project\, upgrading of concrete bridge de cks is planned to be performed by removing about 10cm deep deteriorated to p surface of concrete deck and refilling it with fibre reinforced concrete (FRC) made of normal strength concrete and 1.3 vol.-% of steel fibres wit h length of 30 mm and diameter of 0.5 mm. However\, in order to improve th e load bearing capacity of bridge decks to satisfy the requirements for in creased traffic load\, it is often required to increase the deck thickness . By using Ultra High Performance Fibre Reinforced cement-based Composites (UHPFRC) instead of the FRC\, increase of the deck thickness is avoided d ue to its high tensile and compressive strength. Moreover\, it is not nece ssary to apply waterproofing membrane on top surface of bridge decks becau se UHPFRC has extremely low permeability and functions as protective layer .\nKajima Corporation and NEXCO Central have started a collaborative resea rch project to develop an upgrading method of existing bridge decks using cast-in-situ UHPFRC in 2016. In this presentation\, results obtained from the first stage of the research are explained briefly. The UHPFRC mix used in the research is characterised by its matrix densified by ettringite (A Ft) formation\; thus\, it is called “AFt-UHPFRC”. The AFt-UHPFRC was o riginally developed for fabrication of precast members with thermal curing and hasn’t been applied to existing structures by in-situ casting. In o rder to understand properties of the AFt-UHPFRC\, direct tensile tests and UHPFRC – concrete interfacial bond tests were conducted. The test resul ts were analysed and the necessity to modify the AFt-UHPFRC mix compositio n to be suitable for upgrading of existing concrete bridge decks was ident ified.\n\nBio :  Tohru Makita is structural engineer of NEXCO Central sin ce 2002. He obtained his Bachelor’s and Master’s degree in Civil Engin eering at Kyoto University and Doctor’s degree in Structural Engineering at EPFL. He is currently engaged in management of design\, construction a nd seismic retrofitting of bridges and development and implementation of n ew technologies related to bridges. LOCATION:GC C3 30 https://plan.epfl.ch/?room=GCC330 STATUS:CONFIRMED END:VEVENT END:VCALENDAR