CSIR-Central Building Research Institute

Cork granules are produced as by-products and waste by the cork processing industries that make ‘bottle stoppers’ as a main product. These granules are of low density and could be used as lightweight aggregates for making concrete. This paper describes an investigation carried out to assess the compatibility of cork granules with cement for the manufacture of lightweight cementitious composites. Five different grades of cork granules varying in terms of size and density were investigated. The effects of extractives, particle size and density of the cork granules were studied. The results indicate that these parameters affect cement hydration in a complex way. At lower concentrations of cork (10%), only the extractives have an influence on hydration behaviour. At higher cork concentrations (20% and 30%), however, particle size and density also affect the compatibility. Nevertheless, cork granules are found to be compatible with cement. Korkgranulat entsteht in der korkverarbeitenden Industrie als Neben- und Abfallprodukt bei der Herstellung von Flaschenkorken. Korkgranulat hat eine geringe Dichte und könnte als Leichtzuschlagstoff für die Herstellung von Beton verwendet werden. In diesem Artikel werden die Ergebnisse einer Untersuchung zur Beurteilung der Kompatibilität von Korkgranulat und Zement zur Herstellung von zementgebundenen Verbundwerkstoffen vorgestellt. Unter Verwendung von fünf Korkgranulatarten unterschiedlicher Grösse und Dichte wurde die Wirkung von Extraktstoffen, der Partikelgrösse und der Dichte untersucht. Es zeigte sich, dass sich diese Parameter in komplexer Weise auf die Zementhydration auswirken. Bei geringem Korkanteil (10%) wirken sich nur die Extraktstoffe auf das Hydrationsverhalten aus. Bei höheren Korkanteilen (20 und 30%) beeinflussen jedoch auch die Partikelgrösse und die Dichte die Kompatibilität. Insgesamt gesehen erwies sich Korkgranulat als mit Zement kompatibel.

Various species of wood in the form of chips, particles or fibres are added to cement to make composite materials for building applications. Most wood species are reported to retard the setting of cement and weaken its strength. Cork, which is the bark of Quercus suber trees, is not currently used for making such composites. It differs from other wood species in many aspects. A preliminary study conducted to assess the compatibility of cork with cement found that it is compatible with cement. This paper discusses the difference between the properties of cork and other woods and the advantages these properties bring to cementitious composites. Some physical and mechanical properties of cork cement composite materials are also presented.

Various lignocellulosic materials are available locally from the agro- forestry industries in many parts of the world. Using these materials in a cementitious matrix, composites with a range of properties can be formed. These composites have divers applications in building construction. However, the presence of the extractives in the lignocellulosic materials and their mixing difficulty with cement limit their use. This paper discuss these problems for making cement-bonded products. The properties of the resultant composites and their advantages and limitations are also presented.