Ceramic detachment is a serious problem that persists in modern building constructions despite technological advances and updated regulatory documents. Most of these detachments occur at the interface between the adhesive mortar and the ceramic tile, due to the action of simultaneous tensile and shearing efforts. However, despite this understanding, experimental studies that evaluate the integrity of the adhesion of façades covering materials subjected to simultaneous stress are scarce. In this sense, this study proposes to evaluate the integrity of adhesive mortar joints using the mixed-mode flexure (MMF) crack propagation test. Force and elastic and dissipated energy data were used in this analysis. Prismatic specimens, with a size of 160 × 40 mm2 and a thickness of 6 mm, were produced consisting of two ceramic plates joined by a layer of adhesive mortar at 5 ± 0.5 mm. An acetate film was inserted into one of the mortar–ceramic interfaces in order to simulate the presence of a previous crack, and different crack sizes were used. The results showed the high stress-concentrating effect that the existence of flaws in the interface region has on fracture resistance, as well as the importance of effective contact between the materials. The energy parameters confirmed the analyses carried out based on the load values. The elastic energy of the system fell in the cracked samples, showing that there is a close relationship between the interface energy and the adhesive strength of the material. An energy release of the order of 0.053 ± 0.031 J was required for a 15 mm crack to propagate, creating a fracture surface.
Despite technological advances in the production processes of the materials for ceramic façade coatings, the problems of detachments are still frequent. Therefore, this work aims to investigate, through a literature review, the existing gaps related to the adhesion ability of adhesive mortars, identifying new research needs that can better explain the behavior of the material. In addition, an experimental procedure was developed to evaluate the mechanical capacity of adhesive mortars when subjected to cyclic stresses. Dynamic stress measurements are presented for several blocks of mortar and on similar blocks but with a slot drilled prior to measurements (intended to represent failure). From these data we calculated values of stress energy, elastic energy, and dissipated energy. The experimental results showed that the energy involved in the test process accompanied the load values and current stress values. The mortar samples with the previous failure absorbed and dissipated less energy than mortars without failure, showing that materials that have less energy to dissipate, are materials that have developed less capacity to adhere, that is, to keep their parts together.
The understanding of the mechanical fixation behavior of coatings is crucial for a better comprehension of the bonding systems, especially at the interface between the mortar and the substrate. Physical adherence is related, among other things, to the contents of the materials used in the roughcast and mortar coatings, due to the colloidal water penetration into the pores of the substrate. This work evaluated the influence of different lime solution additions replacing the kneading water in the preparation of roughcast and mortar coatings. Two types of substrates were investigated:ceramic bricks and concrete blocks. Three wall masonry panels were constructed, with dimensions of 220 × 180 cm2, one of concrete block and two of ceramic bricks, followed by the application of roughcast and mortar coating with an average thickness of 5 mm and 20 mm, respectively. Direct tensile bond strength tests were performed and the results, with a 95% confidence level, showed that substrate ceramic and treatment in the roughcast exhibited a better behavior regarding the distribution of the tensile bond strength of the tested specimens. However, no significant differences of the amount of addition used (0%, 5%, 10% and 15%) on the tensile bond strength were observed.
This work presents an extensive numerical simulation to analyze the influence of the coating layers on the performance of construction systems, in order to make the constructions projects feasible, not only economically but also technically. Through numerical simulations based on a defined reference model, the present work studied the influence of different layers of floor, roof and internal and external wall systems, on the acoustic, thermal, and luminous performance of buildings in Brazil. The results showed the materials and elements with the greatest influence on: lighting performance are the internal finishes of the environment and the type of glass used in the external windows. On thermal performance, all elements of the roofing system and façades, especially an absence of external cladding and the use of thermal blankets on the roof, have greater influence. The acoustic performance of the façade function on the external windows and acoustic performance of the floor system are mainly influenced by the thickness of the structural element and the use of a ceiling and acoustic blanket; acoustic performance of internal walls is affected by typology of the structured element of the wall and thickness.