Shotcrete is one of the most important material for tunnel lining and surface finish of land slopes. Compared to normal concrete, the properties of shotcrete changes remarkably by the skill of the workers at the site, such as “nozzle man”. One of the main causes of the change is the “rebound” of materials. To utilize shotcrete as a material for permanent structural lining of tunnels, not only strength properties but also durability aspects of the material must be clarified and the technique to produce high quality shotcrete must be developped. This paper overviews the properties of shotcrete mainly used for tunnel lining through research works done in recent years.

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The share of cement concrete pavement in Japan has been decreasing since 1960s and maintaining about 6% for these years. Cement concrete pavement, however, has been reconsidered because of its high durability and harmonization with environment. This paper discusses the prospect of cement concrete pavement in Japan and outlines technology required in future.

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JIS A 6201 : Fly ash for use in concrete was revised in Feb. 1999. The activity for the revision has been done for three years in order to accelerate the utilization of fly ash in cement-concrete field. A special feature of JIS A 6201-1999 is shown as follows, four kinds of fly ashes; high quality, normal quality corresponding to the old specification, low qualities with high loss on ignition and low blaine value, are specified in the new JIS. This paper describes the background of the revision and the bases of the new specification.

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Cement made with urban refuse incinerator ash as raw materials is effective to save energy and resources and to reduce the discharge of CO₂ gas. However, such type of cement may contain a relatively high chloride content. Recently a manufacturing technology to reduce chloride content in this type of cement has been developed. In this paper, the feature of this type of cement is discussed. On the other hand, fresh and hardened proper-ties as well as durability of concrete made with this type of cement are reported. Test results show that properties of concrete made with this type of cement are similar to those of concrete made with ordinary portland cement.

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