Studies on Lightweight High-Strength Shotcrete
With small deadweight, light-weight shotcrete can avoid the shotcrete lining from falling off, which benefits the bolt-shotcrete support of the roadway better under same bond strength. Light-weight shotcrete can be made by using clay ceramsite, polystyrene particles and fly-ash ceramsite to replace some gravel and sand. The experiments show that the characteristic of fly-ash ceramsite shotcrete is superior to that of clay shotcrete, while by replacing part of gravel and sand with polystyrene particles and fly-ash ceramsite, light-weight high strength shotcrete will have excellent combination properties.
Investigations on the Performance of Shotcrete Using Artificial Lightweight Shale Ceramsite as Coarse Aggregate
In this study, a type of artificial lightweight shale ceramsite (ALSC) was used as the coarse lightweight aggregate for shotcrete (LAS), of which the mechanical properties, chloride penetration ion resistance, and rebound behavior were investigated. Based on the experimental results on compressive, tensile, and bond strength, LAS meet the strength requirements, and the replacement rate of fly ash (FA) and silica fume (SF) are suggested to be kept at ~15% and 10%, respectively, to result in the best mechanical properties of LAS. Adding FA and SF to the mixture significantly improved the chloride ion penetration resistance (CPR) of LAS because of morphology effects and secondary hydration of FA and SF that lead to a denser microstructure of the mixture. The electric flux and chloride ion migration coefficient (DRCM) of LAS decreased by 56% and 67%, respectively, with FA increasing from 0 to 10%. The electric flux and DRCM further decreased by 71% (153C) and 66% (3.24 m2/s), respectively, with FA increasing from 10 to 20%. As 5–10% SF was further added, the electric flux and DRCM of LAS decreased to extremely low levels; for instance, with FA = 10% and SF = 10%, DRCM = 1.61 m2/s, and the electric flux was too small and could be ignored. The contact stresses between aggregate and shotcrete mixtures were measured to investigate the rebound trend of ALSC in shotcrete. According to the analyses of the theoretical model of the rebound behavior of aggregate in shotcrete proposed by Armelin and Banthia, because of the reduced contact stresses between ALSC and mortar and the smaller density of LAS compared with normal-weight aggregate, the rebound rate of ALSC was about half of that of normal-weight aggregate in the shooting process of the shotcrete.
Letting Women in? Gender Mainstreaming in Regional Policies
Gender mainstreaming has over the last ten years become the dominant strategy of integrating gender issues in public policy. This article presents regional policy as a broad and increasingly important policy field to study, and analyses gender mainstreaming in this policy field in the Norwegian and the Swedish contexts. How do problem representations surrounding “gender equality” and “gender mainstreaming” produce meanings of gender as well as construct possibilities for change? The article shows that, despite some differences between the two countries, gender mainstreaming in regional policy can to a large extent be read as meaning “women”. Women are in this context given a narrow subject position and are constructed as lacking what it takes to produce sustainable regional growth. The concluding discussion highlights the relations between the implementation of gender mainstreaming and neo‐liberal political trends.