A review on investigations of novel nano-silica based mortar for the repairing of heritage buildings.

The common building material utilized throughout the ancient world was lime. However, the development of cement quelled its prominence. Although cement was proven to have numerous uses in the construction business, it was determined to be harmful when used as a repair material, especially for historic buildings. The main cause is that the strength and service life related properties of cement are incompatible with the substrate (ancient lime) and masonry units. Nano-silica (NS) is a well-known mineral admixture hence it is taken for analysis. The characterization of NS in lime mortar is studied. From the different historic sites, the mortar's physical properties are determined. After adding 2% NS, in the fly ash concrete the setting time reduced to 90 minutes and predominant, it is reasonable to take for granted that the carbonation reaction plays a key role in the mortar's strength. In this study identified as calcite is primarily composed of fly ash were less resistant to salt crystallization than mortars made of lime that had been substituted with GGBS. When NS was added to cement paste it increases flexural and compressive strength. In place of fly ash, GGBS produced a larger rate of decrease in the water absorption coefficient through capillarity, which is comparable to porosity. These mortars were capable of being used as restoration materials for historic buildings since they closely resembled physical characteristics of ancient mortars. [ABSTRACT FROM AUTHOR]