Pectin Added Cement Pastes

The use of materials derived from plants waste has emerged as a promising alternative for the sustainable development of the cement industry. In this context, pectin has stood out as a potential additive, as it is one of the main components in cell structure, making it a very abundant material that can be extracted without environmental damage. This study evaluated the rheological effect of different concentrations of citric pectin (0.5%, 1%, 2%, and 3% w/w) on the behavior of Portland cement pastes. The additive modified the classic cement hydration pathways by changing the viscosity and the yield stress of the pectin added paste. The flow tests have shown an improvement in the paste workability, while oscillatory tests showed an increase in the storage modulus and a consequent decrease in the initial setting time, as compared to the pristine cement paste. The evaluation of obtained results indicates that this change is associated with the polymer structure and its gelation in an alkaline medium without polymer hydrolysis. Associated to these rheological/structural changes, the low cost of pectin highlights its potential as an effective and eco-friendly additive.