A new durability assessment methodology of thermal mortars applied in multilayer rendering systems

Abstract

The increase of the thermal resistance of building envelopes is a result from the growing demand of energy efficiency. Several new materials and systems emerged in recent years as an answer to that growing need. Thermal mortars applied in thermal rendering systems are an example of how the research community and the building industry try to tackle that challenge.A gap in the durability assessment of thermal rendering systems can however be observed. The existing standardization for the durability assessment of mortars does not allow a consistent evaluation of thermal mortars, especially in multilayer systems. As such, the main goal of the present work consists in proposing a durability assessment methodology of thermal mortars applied as multilayer systems. Accelerated ageing cycles, directly applicable to thermal mortars, were developed through numerical simulation, taking into account material properties, climatic conditions and consequent degradation mechanisms to which the system is subjected.A theoretical methodology for the determination of heat-cold cycles that can represent specific climatic conditions was developed. The implementation of the developed accelerated ageing cycles and the obtained experimental results contributed to the definition of a new durability assessment methodology. This methodology defines the accelerated ageing cycles that should be performed in each climate zone, representative of the main degradation mechanisms. One of the major advantages is the temperature adaption of the accelerated ageing cycles to the climatic conditions. The new methodology contributes to the evaluation of new solutions, during their development stage, and to their adequacy for specific climatic conditions.

Circular economy in cementitious ceramics: Replacement of hydrated lime with a stoichiometric balanced combination of clay and marble waste

“…About the incorporated air, it appears that the use of clay only reduces the content of incorporated air in the material, causing a greater packaging, which is beneficial because it provides less voids in the material. 64,65 It is known that packaging is an effect related to the particle size of the material. Thus, as the marble residue has a less uniform granulometry than the marble residue and hydrated lime (Figure 1), it favors packaging.…”

Development of an Integrated Durability Assessment Methodology of Thermal Mortars Applied in Multi-layer Systems

“…After the implementation of the new hygrothermal ageing cycle, it was possible extrapolating this methodology to the development of a theoretical algorithm. The developed algorithm is capable of defining accelerated heat-cold ageing cycles representative of several European climates (Maia, Ramos, and Veiga, 2019). Figure 3 presents the adopted experimental methodology to evaluate the durability assessment of thermal rendering and plastering systems.…”

“…The characteristics and durability of thermal rendering systems, suitable for the exterior application, were already presented in the previous work of Maia et al (2019). The developed methodology, applicable to thermal rendering systems, combines the previous knowledge of the requirements and material properties (obtained by experimental tests and numerical simulation) with a detailed durability experimental campaign.…”

“…of water spraying, for 1h) and the transitions between the 2 stages, resulting in a 6h cycle, repeated 80 times. This first approach allowed the development of a theoretical methodology for the definition of heat-cold cycles in the European context (Maia et al, 2019).…”

Durability of Thermal Renders with Lightweight and Thermal Insulating Aggregates: Regranulated Expanded Cork, Silica Aerogel and Expanded Polystyrene

“…Moreover, durable solutions in buildings contribute directly to a reduction in the amount of waste produced, air pollutant gases and a more sustainable construction. With this concern, the study of durability is an increasingly important issue in the construction industry, being intrinsically related to the building quality, climatic conditions and the user's quality of life [7,9,10].…”