The effect of sugar on the microstructure of cement paste and its action/mechanism in cement set retardation

Sugar is a good cement set retarder and improves the strength when used in a controlled manner. Strength depends upon the basic skeleton developed by cement pastes. The development of this basic skeleton depends upon a number of factors, including the addition of admixtures. This paper presents how microstructures are modified/amended when sugar is incorporated in cement-paste as a retarding admixture. For this purpose, slides of cement pastes containing different sugar-contents were prepared and monitored with a microscope and photographed. This study supports the mechanism of adsorption of sugar on the hydration products and poisoning their growth, which is essential for continued hydration of cement after the end of induction period. Sugar makes the network of fibrils denser and hence increases the strength. (author)