Glass frit for concrete structures: a new, alternative cementitious material Said Laldji and Arezki Tagnit-Hamou Abstract: With today’s requirements for high-performance concrete, mix proportions containing cementitious materials as partial replacement of, or in addition to, Portland cement, are being used more frequently. The most commonly used cementitious materials nowadays are fly ash, silica fume, and ground, granulated blast-furnace slag. However, alternative supplementary cementitious materials can successfully be used as long as they meet the acceptance criteria stated in various specifications. This paper provides data on properties of structural concrete containing glass frit. The performance of this type of concrete is highlighted by its rheological and mechanical behaviour, as well as its durability. Later-age compressive, splitting tensile, and flexural strengths are well above estimated values, and in many cases, are higher than those obtained with the control concrete. Durability aspects and characteristics expressed by drying shrinkage, surface scaling, and chloride-ion permeability have shown that concrete incorporating glass frit has a very good potential for long-term resistance. Key words: glass frit, cementitious material, workability, mechanical properties, durability. Résumé : Les exigences actuelles sur la qualité des bétons à hautes performances (BHP) rendent l'utilisation des ajouts cimentaires en remplacement partiel ou en addition au ciment portland de plus en plus fréquente. Les matériaux cimen- taires les plus couramment utilisés sont les cendres volantes, les fumées de silice et le laitier broyé de haut fourneau. Cependant, d’autres ajouts cimentaires alternatifs peuvent être utilisés avec succès s’ils rencontrent les critères d’acceptation énoncés dans les spécifications. Cet article présente des données sur les propriétés du béton structural contenant de la fritte de verre. La performance de ce genre de béton est remarquablement mise en évidence par son comportement rhéologique et mécanique ainsi que par sa durabilité. Les résistances en compression, à la traction par fendage et en flexion pour le béton durci sont bien au delà des valeurs estimées et, dans plusieurs cas, supérieures à celles obtenues dans le béton témoin. La durabilité exprimée par le retrait endogène et de séchage, l’écaillage de la surface et la perméabilité aux ions chlore ont montré un très bon potentiel de résistance à long terme. Mots-clés : fritte de verre, ajouts cimentaire, ouvrabilité, propriétés mécaniques, durabilité. [Traduit par la Rédaction] Laldji and Tagnit-Hamou 802 Introduction The use of by-products in the cement industry has three objectives: environmental, economic, and technological. Never- theless, their incorporation in concrete must meet certain criteria stipulated in different standards. The use of cement- itious materials in concrete, either in addition to or in partial replacement of the cement, improves its properties in com- parison with those of concrete produced using plain Portland cement. In recent years, the use of cementitious materials has attracted a lot of interest. Using suitable quantities of such materials not only improves some properties of fresh and hardened concrete, but also has environmental benefits if the materials can be obtained locally. The unavailability of materials such as blast furnace slag, fly ash, and silica fume in many places increases production costs because of ship- ping over long distances, which also causes additional envi- ronmental pollution. This paper provides data on the properties of structural concrete containing glass frit. Research significance Aluminum production in various parts of the world gener- ates a considerable amount of waste, in particular spent pot liners (SPLs), which contain leachable cyanides and fluo- rides, a serious environmental problem. Canada’s primary aluminum production reached 2.59 × 10 6 t in 2004 (AAC), making it the world’s third largest aluminum producer. Every 100 t of primary aluminum gen- erates up to 2 t of SPLs, from which up to 3 t of glass frit can be produced. Glass frit is an engineered material made from recycled SPLs as the major raw material. Concrete made with ground glass frit as cement replacement has shown better rheological and mechanical behaviour than Portland cement concrete (Tagnit-Hamou and Laldji 2004). Along with a laboratory investigation (Laldji and Tagnit-Hamou 2003), field pilot projects were undertaken to 793 Can. J. Civ. Eng. 34: 793–802 (2007) doi:10.1139/L06-168 © 2007 NRC Canada Received 9 May 2005. Revision accepted 5 December 2006. Published on the NRC Research Press Web site at cjce.nrc.ca on 27 July 2007. S. Laldji 1 and A. Tagnit-Hamou. Department of Civil Engineering, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada. Written discussion of this article is welcomed and will be received by the Editor until 30 November 2007. 1 Corresponding author (e-mail: said.laldji@usherbrooke.ca).