ORIGINAL ARTICLE Properties of self-compacting mortars with binary and ternary cementitious blends of fly ash and metakaolin Erhan Gu ¨ neyisi Mehmet Gesog ˘lu Received: 5 April 2007 / Accepted: 17 December 2007 / Published online: 3 January 2008 Ó RILEM 2007 Abstract The link between flow properties and the formulation is actually one of the key-issues for the design of self-compacting concretes (SCC). As an integral part of a SCC, self-compacting mortars (SCMs) may serve as a basis for the design of concrete since the measurement of the rheological properties of SCCs is often impractical due to the need for complex equipment. This paper discusses the properties of SCMs with mineral admixtures. Portland cement (PC), metakaolin (MK), and fly ash (FA) were used in binary (two-component) and ternary (three-component) cementititios blends. Within the frame work of this experimental study, a total of 16 SCMs were prepared having a constant water-binder (w/b) ratio of 0.40 and total cementi- tious materials content of 550 kg/m 3 . Then, the fresh properties of the mortars were tested for mini-slump flow diameter, mini-V-funnel flow time, setting time, and viscosity. Moreover, development in the com- pressive strength and ultrasonic pulse velocity (UPV) of the hardened mortars were determined at 1, 3, 7, 14, and 28 days. Test results have shown that using of FA and MK in the ternary blends improved the fresh properties and rheology of the mixtures when com- pared to those containing binary blends of FA or MK. Keywords Fly ash Á Fresh properties Á Metakaolin Á Self-compacting mortar Á Setting time Á Viscosity 1 Introduction Self-compacting concrete (SCC) is considered as a concrete which can be placed and compacted under its own weight without any vibration effort, assuring complete filling of formworks even when access is hindered by narrow gaps between reinforcement bars. In order to achieve such behavior, the fresh concrete must show both high fluidity and good cohesiveness [1]. Although SCC can be used on most construction sites, its rheological characterization must be improved to better control its placement. Moreover, the fresh SCC must be stable to ensure the homoge- neity of the mechanical strength of the structure. The stability of SCC can be enhanced by incor- porating fine materials such as limestone powder, fly ash (FA), and ground granulated blast furnace slag since an increase in cement content leads to a significant rise in material cost and often has other negative effects on concrete properties (e.g. increased thermal stress and shrinkage, etc.) [2–6]. The use of such powder may provide greater cohesiveness by improving the grain-size distribution and particle packing [7]. Alternatively, a viscosity modifying admixture (VMA) along with a superplasticizer (SP) E. Gu ¨neyisi (&) Á M. Gesog ˘lu Department of Civil Engineering, Gaziantep University, 27310 Gaziantep, Turkey e-mail: [email protected] Materials and Structures (2008) 41:1519–1531 DOI 10.1617/s11527-007-9345-7
Properties of self-compacting mortars with binary and ternary cementitious blends of fly ash and metakaolin
Jul 01, 2023
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