EFFECTS OF DELAYED ETTRINGITE FORMATION COMBINED WITH ALKALI AGGREGATE REACTION ON THE HYDROUS TRANSFER PROCESS IN CONCRETE

Author(s): Renaud-Pierre Martin, Romain Lapeyrère and François Toutlemonde
Paper category: Proceedings
Book title: Proceedings of CONSEC13 Seventh International Conference on Concrete under Severe Conditions - Environment and Loading Volume I
Editor(s): Z.J. Li, W. Sun, C.W. Miao, K.Sakai, O.E. Gjørv, N.Banthia
ISBN: 978-2-35158-124-7
e-ISBN: 978-2-35158-134-6
Publisher: RILEM Publications SARL
Publication year: 2013
Pages: 813-823
Total Pages: 961
Language : English

Abstract: Delayed Ettringite Formation (DEF) and Alkali Aggregate Reaction (AAR) are both internal swelling processes that can affect concrete. They induce expansion, cracking and decrease of the mechanical properties and thus problems in terms of serviceability and safety for the corresponding structures. In the field, they are known to act frequently coupled. To deal with the affected structures, numerical tools are necessary to re-assess and predict their mechanical state. This implies to finely understand the mechanisms and to quantify the couplings between expansions and exposure parameters such as moisture which is one of the most influent. Thus, numerical tools often use a calculation of the hydrous state of the structure as an input data for the mechanical predictive calculations. Expansions may open cracks and are believed to modify the moisture transfer in the materials. Thus, computations of the hydrous state should be coupled to the mechanical calculations to take into account the evolution of the moisture transport. This paper provides preliminary experimental data to quantify the effect of expansion on the evolution of the moisture content and check if it should be implemented in the numerical tools. Tests were performed on specimens affected by DEF coupled with AAR or not and exposed to moisture gradients. Expansions, global and local water content and porosity were measured and then compared to predictive analyses with different assumptions.

Online publication : 2013
Publication type : full_text
Public price (Euros) : 0.00