Review Self-compacting concrete of medium characteristic strength Iliana Rodríguez Viacava a,⇑ , Antonio Aguado de Cea b , Gemma Rodríguez de Sensale a a Instituto de la Construcción, Facultad de Arquitectura, Universidad de la República, C/Hugo Prato 2314, 11200 Montevideo, Uruguay b Escola Tècnica Superior d’Enginyers de Camins, Canals i Ports, Universitat Politècnica de Catalunya, C/Jordi Girona Salgado 1-3, Mod. C1, 08034 Barcelona, Spain article info Article history: Received 26 July 2011 Received in revised form 22 December 2011 Accepted 23 December 2011 Available online 18 January 2012 Keywords: Mix design Self-compacting concrete Medium strength Mechanical properties Durability abstract The wide use of self-compacting concrete (SCC) in the precast industry versus its moderate use in the ready-mixed concrete industry, has led to the development of products within the upper-middle perfor- mance range, leaving gaps unfilled in some applications where low or medium strength is required. The aim of this paper is to demonstrate, theoretically and practically, the feasibility of developing SCC in the range of medium strength. In this study, cement kiln dust (CKD) was used as a local filler, and six mix- tures with different percentages of cement replacement by CKD were investigated. Properties at fresh and hardened state were studied. The use of high percentages of CKD and different combinations of water/ fines ratio allows economizing on the use of the admixture and the amount of cement required, obtaining SCC of medium strength and lower production costs. Ó 2012 Elsevier Ltd. All rights reserved. Contents 1. Introduction ......................................................................................................... 776 2. Conceptual approach .................................................................................................. 777 3. Experimental program ................................................................................................. 778 3.1. Materials ...................................................................................................... 778 3.2. Methodology, mix design and trials ................................................................................. 779 4. Analysis of results and discussion ........................................................................................ 779 4.1. Results in fresh state ............................................................................................. 779 4.2. Results in hardened state ......................................................................................... 780 4.3. Discussion ..................................................................................................... 780 5. Conclusions .......................................................................................................... 781 Acknowledgements ................................................................................................... 781 References .......................................................................................................... 781 1. Introduction Worldwide, the use of self-compacting concrete (SCC) has gained wide acceptance in the precast industry, which has many advantages such as: reduces the total time of construction and the costs, improves work conditions by eliminating vibration, makes easier to achieve a better final product (finish and durabil- ity), allows the use of complex molds and parts with congested reinforcements [1–3]. However, the situation is very different in the case of the ready- mixed concrete industry, as evidenced by the ERMCO statistics [4]. The low use of SCC in European countries, Russia and the United States, ranges from 0.8% to 1.5%. The current use of SCC in buildings made ‘‘in situ’’ is mainly reduced to processes of some complexity: filling parts of special geometry or congested reinforcements, areas of difficult access for vibrators, repairing of existing structures, underground tunnels. Usually, SCC mixtures have high contents of fines in order to obtain the required rheological properties to achieve self- compactability, which usually results in mixtures with high content of Portland cement, and consequently, high values of initial and final strength, much higher than those strictly required 0950-0618/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.conbuildmat.2011.12.070 ⇑ Corresponding author. Tel.: +598 2 401 42 50. E-mail address: rodriguez.iliana@gmail.com (I. Rodríguez Viacava). Construction and Building Materials 30 (2012) 776–782 Contents lists available at SciVerse ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat