Influence of the Mineralogical and Mortar Components on the Adherence of Some “Granites”

Abstract

Rock plate setting can be performed with metal inserts or by mortar adhesion. For mortar setting, the adhesion bond strength values, as a rule, should be above 1 MPa. In the present work, tests with eight types of “granite” tiles were performed to compare the adherence of five types of mortars. The rocks chosen were: Red Brasilia (syenogranite), Black Indian (migmatite), Green Labrador (charnockite), Black Sao Gabriel (hypersthene diorite), Rose Jacaranda (nebulitic migmatite syenogranite), Fantastic Blue (biotite monzogranite megaporphyritic serial gneissified), Grey Swallow (monzogranite) and Yellow Ornamental (garnet porphyroblastic gneiss), which do not have similar petrographic and sawability characteristics, thereby resulting in different initial roughness values of the plates obtained by breaking apart the blocks on the gangsaw machine, which use granulated steel as an abrasive element. The adherence of these rocks with the mortars was determined in the rough surface as well as in the polished surface by the pullout traction test, standardized for ceramics. The results showed that the mortar adhesion is related to roughness, to mineralogy and to the texture of these rocks. To verify this relationship, tensile bond strength tests were performed with the main mineral components of these rocks using single crystals with known optical orientation. Moreover, the microstructure study of the standard substrate/mortar/rock set was also performed.

Adherence of Granite Plates by Mortar Adhesion: Influence of Temperature

“…In this study, the specific mortar grout for granite and marble that is marketed worldwide, here called "Commercial Mortar" was compared with other type, here called "Mortar 3" [6] based on a laboratory-prepared mortar for porcelanate [7]. The reason this was chosen is due to the fact that porcelanate and granite have one characteristic in common, very low porosity (< 3%), does not allow anchoring, and the adherence is related to chemical bonds and/or intermolecular forces.…”

Adhesive mortars for stone plate bonding

“…Its petrographic and textural characteristics (type, percentage, size, shape, and mineral arrangement, etc.) influence the tensile bond strength of plates set with Nogami et al (2012Nogami et al ( , 2013 showed that adhesion spread was directly proportional to the roughness values Rt (mm), indicating that the larger contact surface provides greater physical interaction (Van der Waals connections) since these rocks have extremely low porosity (B1.01 %). Such characteristic limits the anchoring adhesion (mortar penetration into pores).…”

“…The main objective of this paper is to compare the adherence of an industrial bonding mortar for granite against other laboratory-developed mortars, taking into consideration earlier studies (Nogami et al 2012(Nogami et al , 2013 related to the influence of roughness on the plates and the petrographic characteristics of the stones.…”