Cement-cork mortars for thermal bridges correction. Comparison with cement-EPS mortars performance

Abstract

The aim of this paper is to demonstrate the advantage of cork-mortars for renderings when compared to EPSmortars, from a thermal characteristics point of view, namely in steady and unsteady conditions. It was intended to develop specific rendering mortars able to be applied in thermal bridges to reduce condensation effects and heat transfer in buildings envelopes. The impact of this solution is significant, especially in building typologies as framed reinforced concrete structures. Cement mortars and cement-EPS mortars are used as a reference as their properties are easily recognized compared to cement-cork mortars, which are made with by-products from the cork industry. Several studies were made concerning fresh and hardened state behaviour of mortars, namely: rheological and mechanical properties, microstructure evolution with time and thermal behaviour. For a cement based mortar, different cork dosages (from 0% to 80%) were tested (as sand replacement by mass). Microstructural analyses show that the mechanical properties of cement-cork blends are not only controlled by cork's low density, but also by interaction of cork extractives with the cement hydration process. Thermal conductivity presents a linear decrease for an increasing cork dosage in mortars. Concerning the effect on thermal delay, cork-mortars seem to behave better than EPS-mortars.

Dynamic behaviour of bio-based and recycled materials for indoor environmental comfort

“…However, some of the outliers in Figure 11a -such as cock could be attributed to the naturally occurring trapped air pockets and voids between ICB granules (see Figure 12). As presented within (Brás, Leal and Faria, 2013) not only this, but the microstructure of ICB is similar to a honeycomb providing further microscopic voids within the material (demonstrated in Figure 10r). Furthermore, having such a relatively low saturated thermal conductivity value exhibits the difficulty of water ingress to ICB cells in comparison to other materials (such as Wood Fibres).…”

Earthen Plasters Based on Illitic Soils from Barrocal Region of Algarve: Contributions for Building Performance and Sustainability

“…The hardened state characterization of the mortars also followed the DIN 18947 [11], EN 1015 standards [23,24,25] and test procedures currently used by the research team [26]. Prismatic 160 mm x 40 mm x 40 mm samples and circular 90 mm diameter and 20 mm thick samples were prepared in metallic molds, as well as samples of 20 mm mortar layer applied on a surface of 295 mm x 195 mm of hollow bricks.…”

“…Prismatic 160 mm x 40 mm x 40 mm samples and circular 90 mm diameter and 20 mm thick samples were prepared in metallic molds, as well as samples of 20 mm mortar layer applied on a surface of 295 mm x 195 mm of hollow bricks. The mortars were assessed in terms of linear drying shrinkage [11], density [23], flexural and compressive strength [24], adhesive strength [25], as well as thermal conductivity [26] and water vapor adsorption and desorption capacity [11]. The first four tests used the prismatic samples and the adhesive strength test were carried out with mortar layer on brick samples, while for thermal conductivity test the circular samples were used.…”

Integrated approach for school buildings rehabilitation in a Portuguese city and analysis of suitable third party financing solutions in EU

“…In Scenario 1, the objective is to provide walls thermal improvement by using 4 cm of thermal enhanced mortars for thermal rehabilitation (with thermal conductibility equal to 0.1 W/m ºC), developed by the authors [30][31][32].…”