Exploring Tea Polyphenols as a Performance Enhancer for Cement Mortars

Abstract

This study draws inspiration from the chelating abilities of dopamine and tannic acids with Ca2+ in cement-based materials and explores the potential of green tea water (GTW) with tea polyphenols (TP) as the major soluble substance as a natural source of polyphenols available in people’s daily lives. Hydration kinetics analysis reveals that GTW has both retarding and accelerating effects on cement hydration, with the latter being more prominent at lower concentrations. Properly adding GTW to cement can increase the compressive strengths of mortars by up to 16.7% at 3d, 12.2% at 7d, and 18.2% at 28d compared to the blank mortar. The microstructure of the optimal mortar shows grape-cluster-like nanoparticles that originate from the TP∼Ca intermediates that act as seeds for more hydration products. This effect is confirmed by using analytically pure TP to analyze its influence on the compressive strength of mortar.