What factor affects the adhesion of mortar to surfaces, specifically not applying to the curing of cement?

The adhesion of mortar to surfaces is significantly impacted by porosity because it directly affects how well the mortar can bond with the substrate. A porous surface allows for better penetration of the mortar, enabling it to form a stronger mechanical bond as it fills the voids within the material. When mortar is applied to a porous substrate, it can create interlocking points that enhance the adhesion.

In contrast, surfaces that are too dense or non-porous may not allow the mortar to grip effectively, which can lead to inadequate bonding and potential failures. Understanding the porosity of materials helps builders choose the right type of mortar and surface preparation techniques to ensure a solid connection.

While temperature, humidity, and color can influence other factors in the application and performance of mortar, they do not directly pertain to the ability of the mortar to bond with the substrate like porosity does. Temperature and humidity can affect the curing process, and color does not play a role in adhesion but rather in aesthetics.