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Shikoku Electric Power Co., Inc. has developed the technology to manufacture a brand name "Finash" about 12 years ago, by sorting and classifying coal ash generated in coal fired power plants. "Finash" is highly functional fly ash (HFA) is produced by removing irregular coarse particles. It is important for the production of HFA to minimize the variation in quality of coal ash with sophisticated classification technique and extracting good-quality spherical fine particles. It is now widely utilized as concrete admixture for general civil engineering structures and buildings in Japan. When highly functional fly ash (HFA) is used as shotcrete admixture to substitute for fine aggregate of 100kg/m³, the shotcrete has the advantages of decreasing the amount of dust and rebound during spraying operation, improving the hardened properties of concrete, etc. Therefore, it has been applied in many tunnel construction projects. This paper discusses about the various characteristics such as construction placement, strength, neutralization and dry shrinkage of shotcrete using highly functional fly ash (HFA), using the results that is obtained from spray test in an actual road tunnel.

This paper takes drilling in construction building from a research objective. It covers the research done for the dust concentration distribution under the conditions of different wind velocity, different diameter, different rotation speed and different air pressure by using Fluent. At the same time, the sensitivity of four factors and the relations among the factors were analyzed. Study shows that in the process of diffusion, the concentration of dust first drops slowly, then sharply and last, gradually drops to zero. The biggest factor is the wind velocity, followed by rotation speed. When the wind velocity is controlled in 2.4m/s, increasing the wind velocity can effectively reduce the dust concentration, if the rotation speed is smaller, the concentration of dust is smaller. Combined with this case, the paper puts forward the optimal wind velocity is 2.4 m/s, the optimal rotation speed is 15 m/s.