Enhancing the properties of carbonation cured gamma dicalcium silicates (γ-C₂S) using biomimetic molecules

Abstract

This study investigates the effectiveness of three different organic molecules to enhance the properties of carbonated gamma dicalcium silicate (γ-C₂S) based cementitious system. These molecules are addressed as biomimetic molecules due to their ability to mimic the biomineralization process. Low dosages (2.5% and 5%) of L-aspartic acid (LAsp), L-glutamic acid (LGlu) and polyacrylic acid (PAA) were incorporated to the γ-C₂S paste. The effects of these molecules on the microstructure, CO₂ sequestration capacity and strengths of the CO₂-activated γ-C₂S pastes were monitored. To understand the effectiveness of molecules at different temperature, the compressive and flexural strengths of γ-C₂S pastes carbonated at 25 °C and 50 °C were evaluated. It was observed that all the molecules enhanced the strength of the composites by altering the CaCO₃ formation and subsequent densification of the matrix. However, the effectiveness of the molecules varies depending on the temperature. Specifically, LGlu and LAsp were found to be the most and the least, respectively, effective molecule at high temperature (50 °C) carbonation curing condition; whereas, PAA remained nearly equally effective at both temperatures.

Keywords:

• Carbonation
• gamma dicalcium silicates
• biomimetic molecules
• microstructure
• nano-mechanical performance
• mechanical strength

Acknowledgments

Funding for this research was provided by the US National Science Foundation (NSF # ECI -2028462). All opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the funding agencies.

Disclosure statement

The authors report there are no competing interests to declare.