Search

By reutilizing industrial byproducts, inorganic cementitious alkali-activated materials (AAMs) contribute to reduced energy consumption and carbon dioxide (CO2) emissions. In this study, coal gangue (CG) blended with ground granulated blast furnace slag (GGBFS) was used to prepare AAMs. The research focused on analyzing the effects of the GGBFS content and alkali activator (i.e., Na2O mass ratio and alkali modulus [SiO2/Na2O]) on the mechanical properties and microstructures of the AAMs. Through a series of spectroscopic and microscopic tests, the results showed that the GGBFS content had a significant influence on AAM compressive strength and paste fluidity; the optimal replacement of CG by GGBFS was 40–50%, and the optimal Na2O mass ratio and alkali modulus were 7% and 1.3, respectively. AAMs with a 50% GGBFS content exhibited a compact microstructure with a 28 d compressive strength of 54.59 MPa. Increasing the Na2O mass ratio from 6% to 8% promoted the hardening process and facilitated the formation of AAM gels; however, a 9% Na2O mass ratio inhibited the condensation of SiO4 and AlO4 ions, which decreased the compressive strength. Increasing the alkali modulus facilitated geopolymerization, which increased the compressive strength. Microscopic analysis showed that pore size and volume increased due to lower Na2O concentrations or alkali modulus. The results provide an experimental and theoretical basis for the large-scale utilization of AAMs in construction. [ABSTRACT FROM AUTHOR]

This critical textual analysis examines the symbolic annihilation of race and racisms by the use of hashtags, such as #BBQBecky and #CornerstoreCaroline, in news coverage of White people in the United States who called or threatened to call 911 to report everyday behavior of Black individuals in 2018. This study argues that the use of humorous and virtual hashtags to represent the callers contributed to overall coverage of racially charged incidents in ways that reduced the events' seriousness in terms of social policing of Black individuals. Collectively, this coverage formed a type of symbolic annihilation of racist interpretations of callers' acts and Black resistance and meanings embedded within the hashtags themselves. [ABSTRACT FROM AUTHOR]