Will Blended-Cement Systems with Similar Chloride Penetration Potentials Resist Similarly to Corrosion?

The capacity of concrete to prevent chloride ions penetration represents a key durability factor for steelreinforced structures exposed to de-icing salts and/or marine environments. Although blended-cement systems are commonly characterized with accelerated chloride penetration tests developed for Portlandcement concrete (e.g. the ASTM C1202 method), their microstructures and pore solutions are very different. This study aims to illustrate how the full potential of blended-cement systems to resist chloride ingress (and thus, chloride-induced corrosion) may not be justly disclosed by these accelerated tests using electrical current, even when tested after three months of curing. A Portland-cement-only mortar and five binary blended-cement mortars containing typical dosages of fly ash, slag, metakaolin, glass powder or rice husk ash were characterized using the ASTM C1202 chloride penetration test, bulk resistivity measurements and pore solution resistivity measurements. The results showed similar very low chloride penetration potential after three months for the investigated systems (except for the slag system which showed a low potential). The microstructure was densified with time particularly for systems with fly ash or glass powder, as shown by comparing bulk resistivity measurements after three months and one year of curing. However, measurements of the pore solution resistivity suggested a reinterpretation of the observed trends and the glass powder showed unique features for long-term resistance to chloride-induced corrosion. Finally, this work illustrates the importance of understanding the effects of supplementary cementitious materials on both the microstructure and the pore solution, while motivating further work on complementary aspects such as chloride migration coefficients, chloride binding, porosity distribution, or interfacial transition zone

Variation in the use of recombinant activated factor VII in critical bleeding

Background: Recombinant activated factor VII (rFVIIa) is being increasingly used as a treatment option in settings of uncontrolled bleeding. Despite this, national practice guidelines are lacking, resulting in widespread practice variation between providers. This investigation aimed to describe the differences in use of rFVIIa across Australian and New Zealand hospitals. Methods: Data were extracted from the Haemostasis Registry that collects both contemporaneous and retrospective cases of off-licence (i.e. in nonhaemophilia patients) rFVIIa use in participating institutions. Hospitals were classified according to geographical location and service provision. Results: 2075 cases from 87 hospitals were recorded on the Haemostasis Registry. Across all hospital categories, over 41% of cases received rFVIIa in relation to cardiac surgery. Case complexity varied between providers, with large urban centres treating more severely ill patients. This was reflected in significant differences in the use of blood components and products before rFVIIa administration. Despite differences in patient complexity and use of blood products between hospital categories, response to treatment and patient outcomes remained similar across providers, with survival rates ranging from 68.29% to 70.41%. Conclusion: This is the largest study of off-licence use of rFVIIa. There is significant regional variation in the administration of rFVIIa in Australian and New Zealand hospitals, with little documentation of adherence to guidelines. National consensus guidelines based on available evidence should be developed and promulgated to ensure optimal outcomes.C. D. Willis, P. A. Cameron and L. Phillip