A bio-inspired, plant-derived admixture for metakaolin blended cement mortars

Partially replacing ordinary Portland cement (OPC) with metakaolin (MK) can refine the pore structure, improve mechanical properties, and enhance durability of concretes. However, MK tends to agglomerate due its high surface area concentration hydroxyl groups. To overcome this problem, study exploits a plant-derived polyphenol, tannic acid (TA), as an eco-friendly admixture disperse MK. Due similar chemical functional groups adhesive protein in mussel byssus, TA adhere various surfaces like mussel’s protein. An experimental program was carried out characterize treated investigate effects proposed method on properties paste mortar. After mixing MK, be adsorbed particles, achieving deflocculation dispersion mineral grains by electrostatic repulsion forces steric effect, significantly improving workability Pore structure analysis suggests that densifies hydration products, revealed much-reduced gel interhydrate pores. The nanoindentation results indicated all low-density calcium hydrate silicate (CSH) converted density dispersion, leading drastic improvement compressive strength produced mortars. As result, 28 days mortar prepared dispersed enhanced up 97 % compared one without substitution, which exhibits great potential reducing carbon footprint cement-based construction materials.