BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:A few topics related to long-term time-dependent deformations of c
 oncrete - Dr Matthieu Vandamme\, École Nationale des Ponts et Chaussées
DTSTART:20180316T150000Z
DTEND:20180316T160000Z
UID:TALK103051@talks.cam.ac.uk
CONTACT:Karen Mitchell
DESCRIPTION:Concrete is the most widely manufactured material in the world
 . But concrete creeps (i.e.\, slowly deforms over time under the action of
  a mechanical load)\, at a rate which can lead to excessive deformations o
 r excessive relaxations of prestress\, and hence be detrimental to the lif
 espan of civil engineering infrastructures. In this presentation\, we will
  cover a few topics related to long-term time-dependent deformations of co
 ncrete.\nFirst\, we will show how small-scale measurements\, namely micro-
 indentations performed on cement paste\, make it possible to estimate in m
 inutes a long-term creep kinetics of concrete which is usually measured in
  months with regular macroscopic experiments.\nThen\, the case of the long
 -term mechanical behavior of the containment buildings of French nuclear p
 ower plants will be addressed. Those buildings are biaxially prestressed c
 oncrete structures. Due to the biaxiality\, a prediction of the evolution 
 over time of such prestress requires a knowledge of the full 3-dimensional
  viscous behavior of concrete. From an exhaustive analysis of tests availa
 ble in the literature\, we will show that considering the viscoelastic Poi
 sson's ratio of concrete to be constant over time is a good approximation.
 \nFinally\, we will focus on the case of concrete samples that are sealed 
 (i.e.\, exchange no water with the surroundings) and not loaded mechanical
 ly. Such samples deform over time\, the deformation being called autogenou
 s shrinkage. From an exhaustive analysis of tests available in the literat
 ure\, we will show that the long-term kinetics of autogenous shrinkage can
  be the manifestation of the creep of the concrete solid skeleton under th
 e action of capillary forces due to self-desiccation.\n\nMatthieu Vandamme
  is a Civil Engineer who has been working since 2008 at Laboratoire Navier
  (ENPC\, CNRS\, IFSTTAR) at École Nationale des Ponts et Chaussées. He i
 s interested in materials relevant for Civil and Environmental Engineering
  (i.e.\, concrete\, clay-based materials\, rocks\,…). More precisely\, h
 is main focus lies in the mechanics and physics of porous solids.\nHe rece
 ived his PhD from the Civil and Environmental Engineering department at MI
 T (Cambridge\, MA) in 2008\, for a study of the creep properties of cement
 itious materials by nanoindentation. He is also engineer from Ecole Polyte
 chnique (France) and from École Nationale des Ponts et Chaussées (France
 )\, and received an M.S. in solid mechanics from École Nationale des Pont
 s et Chaussées in 2002.\nMatthieu Vandamme is a French Government By-Fell
 ow at Churchill College and a visitor at the Department of Engineering\, U
 niversity of Cambridge.\n\n\n
LOCATION: Cambridge University Engineering Department\, LT6
END:VEVENT
END:VCALENDAR