日本語フィールド
著者：Aso, K., Usui, H., Sindete, M. J., Some, D. D., Afif, F. M. and Hino, T.題名：Strength development characteristics of improved soil with different water-cement ratios and mixing times in Hasuike clay発表情報：Proceeding of the 21st Southeast Asian Geotechnical Conference and 4th AGSSEA Conference (SEAGC-AGSSEA 2023)キーワード：Soft ground, Unconfined compressive strength, W/C ratio, Mixing time概要：抄録：The deep mixing method is commonly employed in lowland areas of Saga Prefecture. In these applications, the watercement ratio (W/C) is typically set at 1.0. However, engineers often exhibit psychological and experiential factors that influence this decisionmaking process. Concerns such as resistance to adding more water when improving soft ground and apprehension regarding vertical and horizontal displacement during column construction due to insufficient mixing may play a role. This study aims to investigate the strength development characteristics of improved soil by examining different W/C ratios from a mixing time perspective through laboratory tests. The test specimens utilized the upper member of the Hasuike layer. In the laboratory tests, the cement-based binder (C) with a dosage of 110 kg/m3 was employed, and two different mixing times (t) of 3 and 5 minutes were considered. The preparation of specimens adhered to the specifications outlined in JGS 0821-2020. After 28 days of curing, unconfined compression tests (UCT) were conducted, this experiment was repeated twice. As a result, at t=3 min, there is a difference in the experimental results for any W/C, but at t=5 min, no difference can be seen. Stirring for t=5 min improves mixing and clarifies differences due to W/C. For a W/C ratio of 0.5, a higher coefficient of variation (CV) and lower qu values were observed from t=1 min to 5 min, indicating the poorest mixing condition compared to the other W/C ratios. However, after t=10 min, the mixing condition improved. When considering a W/C ratio of 1.0, the CV decreased from t=1 min to 5 min, while qu increased, demonstrating an enhanced mixing state after t=5 min. In the case of a W/C ratio of 1.5, qu increased and CV decreased after t=5min of mixing, indicating a better mixing state compared to the ratios of 0.5 and 1.0.英語フィールド
Author：Aso, K., Usui, H., Sindete, M. J., Some, D. D., Afif, F. M. and Hino, T.Title：Strength development characteristics of improved soil with different water-cement ratios and mixing times in Hasuike clayAnnouncement information:Proceeding of the 21st Southeast Asian Geotechnical Conference and 4th AGSSEA Conference (SEAGC-AGSSEA 2023)Keyword：Soft ground, Unconfined compressive strength, W/C ratio, Mixing timeAn abstract：The deep mixing method is commonly employed in lowland areas of Saga Prefecture. In these applications, the watercement ratio (W/C) is typically set at 1.0. However, engineers often exhibit psychological and experiential factors that influence this decisionmaking process. Concerns such as resistance to adding more water when improving soft ground and apprehension regarding vertical and horizontal displacement during column construction due to insufficient mixing may play a role. This study aims to investigate the strength development characteristics of improved soil by examining different W/C ratios from a mixing time perspective through laboratory tests. The test specimens utilized the upper member of the Hasuike layer. In the laboratory tests, the cement-based binder (C) with a dosage of 110 kg/m3 was employed, and two different mixing times (t) of 3 and 5 minutes were considered. The preparation of specimens adhered to the specifications outlined in JGS 0821-2020. After 28 days of curing, unconfined compression tests (UCT) were conducted, this experiment was repeated twice. As a result, at t=3 min, there is a difference in the experimental results for any W/C, but at t=5 min, no difference can be seen. Stirring for t=5 min improves mixing and clarifies differences due to W/C. For a W/C ratio of 0.5, a higher coefficient of variation (CV) and lower qu values were observed from t=1 min to 5 min, indicating the poorest mixing condition compared to the other W/C ratios. However, after t=10 min, the mixing condition improved. When considering a W/C ratio of 1.0, the CV decreased from t=1 min to 5 min, while qu increased, demonstrating an enhanced mixing state after t=5 min. In the case of a W/C ratio of 1.5, qu increased and CV decreased after t=5min of mixing, indicating a better mixing state compared to the ratios of 0.5 and 1.0.