Effects of sucrose on fresh-state and setting properties of air lime

The use of sustainable additives such as sucrose for improving the properties of lime-based materials can contribute to a wider use of such low-carbon binders with applications in both civil engineering and conservation of the built heritage. Various sucrose-modified lime pastes were prepared, and their microstructure, fresh and hardened properties, and carbonation rate were assessed with an array of analytical techniques. It was found that sucrose acts as a water-reducing agent with relevant effects on both, fresh and hardened properties of pastes while allowing carbonation to occur homogeneously across the whole sample without the formation of carbonation rims. Such effects were enhanced when sucrose was added to the mixture after the slaking as pastes show higher mechanical strength and carbonate at a slower rate. When sucrose was added before the slaking, pastes show high elasticity, low mechanical strength, and carbonate faster due to their fine microstructure.