Scientific rationale and guidelines to use cane sugar as a performance enhancer in lime mortars

The lack of guidelines and scientific knowledge on heritage materials has often led to aggravating damage in heritage structures. Developing a compatible repair binder for heritage preservation requires addressing several factors. Cane sugar is a widely used performance enhancer in lime mortars; however, there are no guidelines or data available on the dosage, form and application of the material. The work is an effort to engineer and document the techniques of adding cane sugar in appropriate quantities while monitoring its influence on further carbonation. The science governing the action of cane sugar in fermented and non-fermented form is elucidated in the current study. The addition of 1% non-fermented cane sugar led to a retention time greater than 6 h, while with fermented dosage, the retention time is reduced to 3 h. Fermented cane sugar addition supported early age compressive strength, while the non-fermented form supported slow carbonation with enhanced later age strength. However, the rate of carbonation/strength gain is higher in non-fermented cane sugar added mortars. The study classifies cane sugar as an effective water reducer, retainer, plasticiser and a reaction regulator; and proposes its application methods and influence in lime binders, which will enable attaining control and precision on formulating lime binders.