Mechanical properties and durability of alkali-activated steel slag-blastfurnace slag cement

Alkali-activated cement(AAC)is either clinker-less or free,and it is also environmentally friendly due to its low carbon footprint and wide range sources.Industrial wastes,like steel slag and blastfurnace slag,usually have latent hydraulic reactivity,and can be used as precursors of AAC.Both clinkerless and clinker-free AAC were prepared from the mixture of steel slag and blastfurnace slag by using water glass as an activator,and four different recipes which satisfied the strength requirement of 42.5R Portland cement were obtained.Each recipe of AAC exhibited better resistance to sulfate attack and frost attack than Portland cement.AAC showed huge drying shrinkage,but it was equivalent to that of Portland cement as steel slag content increased to 40%.The AAC also had quite low risk of alkali-aggregate reaction.Microstructure analysis showed that the major products were calcium silicate hydrate(C–S–H),calcium aluminosilicate hydrate(C–A–S–H)and zeolite-like phases.Ettringite was also detected in the binder when gypsum was contained in the precursors.

Evaluation of the Effects of Standard Rescue Procedure on Severe Trauma Treatment in China

Background：This study aimed to evaluate the effects of standard rescue procedure （SRP） in improving severe trauma treatments in China.Methods：This study was conducted in 12 hospitals located in geographically and industrially different cities in China.A standard procedure on severe trauma rescue was established as a general rule for staff training and patient treatment.A regional network （system） efficiently integrating prehospital rescue,emergency room treatments,and hospital specialist treatments was built under the rule for information sharing and improving severe trauma treatments.Treatment outcomes were compared between before and I year after the implementation of the SRP.Results：The outcomes of a total of 74,615 and 12,051 trauma cases were collected from 12 hospitals before and after the implementation of the SRP.Implementation of the SRP led to efficient cooperation and information sharing of different treatment services.The emergency response time,prehospital transit time,emergency rescue time,consultation call time,and mortality rate of patients were 24.24 ± 4.32 min,45.69 ± 3.89 min,6.38 ± 1.05 min,17.53 ± 0.72 min,and 33.82% ± 3.87% （n =441）,respectively,before the implementation of the standardization and significantly reduced to 10.11 ± 3.21 min,22.39 ± 4.32 min,3.26 ± 0.89 min,3.45 ± 0.45 min,and 20.49% ± 3.11%,separately （n =495,P 〈 0.05） after that.Conclusions：Staff training and SRP can significantly improve the efficiency of severe trauma treatments in China.