Effects of amino acids on the multiscale properties of carbonated wollastonite composites

This article presents an insight into the effects of amino acids on the moisture susceptibility, nanomechanical properties, and fracture properties of carbonated wollastonite composites. Paste samples containing various concentrations of amino acids were subjected to a CO₂-rich environment. The addition of amino acids resulted in the formation of amorphous calcium carbonate (ACC), vaterite, and aragonite, instead of calcite, in the carbonated composites. Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and nanoindentation were performed for microstructural analysis. Inductively coupled plasma-optical emission spectrometry (ICP-OES) was performed to determine the leaching of Ca²⁺ and Si²⁺ ions from carbonated wollastonite composites. It was observed that the chain lengths of the amino acids have an influence on the formation of crystal phases. For determining fracture properties, the Jenq-Shah model was performed using a notched beam. It was observed that amino acids reduced carbonation reaction and improved fracture properties by 156 %. The formation of metastable CaCO₃ enhanced the nanomechanical properties of this carbonated system.