EARLY AGE SHRINKAGE OF NATURAL AND RECYCLED AGGREGATE CONCRETE

Author(s): Andrzej A. Ajdukiewicz and Alina T. Kliszczewicz
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: 565-576
Total Pages: 961
Language : English

Abstract: For long time the structural influence of the phenomenon of early shrinkage of concrete has been either not recognised or neglected. Since introduction into practice high classes of concrete the early shrinkage together with thermal effects of cement hydration have become the reason of early cracks. In severe conditions it caused rapid decrease of durability of concrete structures. The Standards still indicate the age of concrete at the start of shrinkage measurement as 24 hours. Sometimes, when rapid cements are used, in the first 24 hours even 2/3 of total shrinkage may occur. The paper presents main results of short-term and long-term tests of shrinkage. Different mixtures with various kinds of components were taken into consideration. Particularly, the tests were focused on mixtures with natural aggregates (NAC) and recycled aggregates (RAC) in the range of concrete strength 30 MPa to 110 MPa. Special devices were prepared to allow the early shrinkage measurements immediately after placing concrete in forms. The significant differences in the development of shrinkage were obtained in various mixtures. Some additional observations were recorded for recycled aggregate concretes where ‘internal curing’ caused by water presence in the initially saturated coarse aggregate influenced the properties of concrete.

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