Validation of alternative methodologies by using capillarity in the determination of porosity parameters of cement-lime mortars

The capillary mechanisms in mortars were investigated in this study by using different cement-lime mortar compositions commonly used in coatings and repair mortars. Two types of natural sand (maximum diameter of 1.2 and 2.4 mm) were used in water absorption by capillarity, water absorption by immersion and boiling, and mercury intrusion porosimetry tests. The results obtained were validated by Darcy's Law for water flow in a porous medium. Findings from this study showed that mixed-binder mortars of 1:1:6 and 1:2:9 (cement: lime: sand), and cement mortars 1:3 (cement: sand) exhibited a direct relationship with the results obtained by Darcy's law. Hence, such a method can be used in determining the percentile of capillary pores in mortars. Results from this study also showed that lime mortars with a composition of 1:3 (lime: sand) do not comply with Darcy's law due to the intrinsic properties of the binder, such as hygroscopicity.

Automated summary

This study investigated the capillary mechanisms in mortars and the porosity rate by using different cement-lime mortar compositions. The results showed a direct relationship between certain compositions and Darcy's law, which can be used to determine the percentile of capillary pores in mortars. Lime mortars, however, did not comply with Darcy's law due to their intrinsic properties.