Sandra Raquel Leite Cunha

Mortars based in different binders with incorporation of phase-change materials: Physical and mechanical properties

In a society with a high growth rate and increased standards of comfort arises the need to minimise the currently high-energy consumption by taking advantage of renewable energy sources. The mortars with incorporation of phase-change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reduction in the use of heating and cooling equipment, using only the energy supplied by the sun. However, the incorporation of phase-change materials in mortars modifies its characteristics. The main purpose of this study was the production and characterisation in the fresh and hardened state of mortars with incorporation of different contents of PCM in mortars based in different binders. The binders studied were aerial lime, hydraulic lime, gypsum and cement. For each type of binder, different mortars were developed with different content of PCM. The proportion of PCM studied was 0, 20, 40 and 60% of the mass of the sand. It was possible to observe that the incorporation of PCM in mortars caused differences in properties such as workability, microstructure, compressive strength, flexural strength and adhesion.

Influence of Adding Encapsulated Phase Change Materials in Aerial Lime Based Mortars

Increasingly in a society with a high growth rate and standards of comfort, the need to minimize the currently high energy consumption by taking advantage of renewable energy sources arises. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing for an increase in the level of thermal comfort and reduction of the use of heating, ventilation and air conditioning (HVAC) equipment, using only the energy supplied by the sun. However, the incorporation of PCM in mortars modifies some of its characteristics. Therefore, the main objective of this study was the characterization of mortars doped with two different phase change materials. Specific properties of different PCM, such as particle size, shape and enthalpy were studied, as well as the properties of the fresh and hardened state of these mortars. Nine different compositions were developed which were initially doped with microcapsules of PCM A and subsequently doped with microcapsules of PCM B. It was possible to observe that the incorporation of phase change materials in mortars causes differences in properties such as compressive strength, flexural strength and shrinkage. After the study of the behaviour of these mortars with the incorporation of two different phase change materials, it was possible to select the composition with a better compromise between its aesthetic appearance, physical and mechanical characteristics.

Thermal mortars with incorporation of PCM microcapsules

The main purpose of this work is the production of a mortar with incorporation of Phase Change Materials (PCM) microcapsules, which must have a compromise between workability, mechanical strength and aesthetic appearance. The mortars studied in this work are mixed mortars of lime and gypsum. The proportion of PCM is 0 %, 10 %, 20 % and 30 %. In order to minimize some problems associated with shrinkage and consequent cracking of the mortars, the incorporation of nylon fibers, superplasticizer and gypsum was tested. A study of mechanical characteristics and some sensitivity tests for qualify the shrinkage of the fifteen compositions was realized. In this way, one composition for the application in tests cells was selected, with the aim of studying the thermal behaviour of these mortars. The test performed on test cells includes the study of a standard mortar without addition of PCM and a mortar with incorporation of an ideal percentage of PCM. Based on the obtained results it was possible to conclude that the incorporation of PCM microcapsules in the studied mortars causes an increase in mechanical strengths and shrinkage. The tests performed on test cells allowed to verify a time lag in maximum and minimum temperatures, as well as a slight attenuation in the temperature variation. It can be concluded that the use of PCM microcapsules in mixed mortars of lime and gypsum can be assumed as a viable solution for applications in the construction industry once these present a compromise between their resistance, aesthetic appearance and thermal behaviour.

Mortars with incorporation of phase change materials for thermal rehabilitation

ABSTRACT The thermal rehabilitation is an opportunity to reach higher levels of energetic performance, reducing the high energetic dependence of the countries. Rehabilitation operations based in the utilization of materials with the capability to store and release energy contribute to obtain more energy efficient buildings. Combining the use of smart materials with temperature control capability and renewable energy sources, it is possible to increase the thermal comfort inside the buildings. The main purpose of this study was the physical, mechanical, and thermal characterization of mortars based in specific binders for rehabilitation with incorporation of phase change materials (PCM). Mortars without and with incorporation of PCM were studied. It was observed that the incorporation of PCM in mortars caused differences in the physical and mechanical properties and improved their thermal behavior, reducing the extreme temperatures and decreasing the heating and cooling needs.

Argamassas com incorporação de Materiais de Mudança de Fase (PCM): Caracterização física, mecânica e durabilidade

O despertar da consciencia ambiental pela sociedade, tem levantado problemas ate entao ignorados tais como os consumos energeticos. Numa sociedade com um elevado ritmo de crescimento e padroes de conforto cada vez maiores, surge a necessidade de minimizar os elevados consumos energeticos, tirando partido de fontes de energia renovaveis. As argamassas com incorporacao de materiais de mudanca de fase (PCM) possuem a capacidade de regular a temperatura no interior dos edificios, contribuindo desta forma para o aumento do nivel de conforto termico e diminuicao do recurso a equipamentos de climatizacao, apenas com recurso a energia solar. Contudo, a incorporacao de materiais de mudanca de fase em argamassas modifica algumas das suas principais caracteristicas. Portanto, o principal objetivo deste estudo consistiu na caracterizacao fisica e mecânica de argamassas aditivadas com PCM, assim como na avaliacao da sua durabilidade. Para tal foram desenvolvidas 12 composicoes distintas, a base de diferentes ligantes e dopadas com 40% de PCM. Tendo sido possivel observar que a incorporacao de PCM provoca diferencas significativas em propriedades tais como a trabalhabilidade, resistencia a compressao, resistencia a flexao, aderencia, absorcao de agua por capilaridade, absorcao de agua por imersao e resistencia a acoes de gelo-degelo. Contudo, foi possivel concluir que a incorporacao de PCM nas argamassas pode ser realizada com sucesso. Sendo que, as alteracoes verificadas nas argamassas podem ser contornadas atraves da incorporacao de uma maior dosagem de ligante, superplastificante e ate mesmo a inclusao de fibras. Apesar dos resultados desta investigacao serem promissores e importante referir que outras investigacoes devem ser realizadas com o intuito de observar a influencia do PCM em argamassas constituidas por outros materiais.

Mortars with Phase Change Materials: Contribute to Sustainable Construction

In a society with a high growth rate and increased standards of comfort arises the need to minimize the currently high energy consumption by taking advantage of renewable energy sources. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reduction of the use of heating and cooling equipment, using only the energy supplied by the sun. This paper aims to contribute to the study of mortars incorporating PCM. The main characteristics of the material and the mortars doped with PCM, will be presented. It also aims to clarify the differences in the physical and mechanical characteristics of mortars doped with different types of PCM.

Mortars with phase change materials - Part II: Durability evaluation

The industry of construction is responsible for the high consumption of raw materials, energy and waste production. As such, it becomes imperative to develop and study new constructive solutions with greater sustainable value. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reducing the use of heating and cooling equipment, using only the energy supplied by the sun. However, the incorporation of phase change materials in mortars modifies its characteristics. The main focus of this study was the durability of mortars with PCM incorporation based in different binders. The binders studied were aerial lime, hydraulic lime, gypsum and cement. For each type of binder, different mortars were developed with different content of PCM. The proportion of PCM studied was 0% and 40% of the mass of the sand. It was possible to observe that the incorporation of PCM in mortars caused differences in properties such as water absorption by capillarity, water absorption by immersion and degradation after freeze-thaw cycles.

Mortars with Phase Change Materials - Part I: Physical and Mechanical Characterization

In a society with a high growth rate and increased standards of comfort arises the need to minimize the currently high energy consumption by taking advantage of renewable energy sources. The mortars with incorporation of phase change materials (PCM) have the ability to regulate the temperature inside buildings, contributing to the thermal comfort and reduction of the use of heating and cooling equipment, using only the energy supplied by the sun. However, the incorporation of phase change materials in mortars modifies its characteristics. The main purpose of this study was the production and characterization in the fresh and hardened state of mortars with incorporation of different contents of PCM in mortars based in different binders. The binders studied were aerial lime, hydraulic lime, gypsum and cement. For each type of binder, different mortars were developed with different content of PCM. The proportion of PCM studied was 0%, 20%, 40% and 60% of the mass of the sand. It was possible to observe that the incorporation of PCM in mortars caused differences in properties such as workability, microstructure, compressive strength, flexural strength and adhesion.

TrivPlat: A monitoring, management and evaluation tool for electronic public procurement

Bad decisions in public procurement processes have two negative effects: price increase of public goods and services with an impact on public expenditure, and adversely effects on competition, with the negative result of loss of efficiency and social welfare. Electronic public procurement (EPP) has been considered an important tool for promoting competition, simplifying and ensuring transparency in decision-making processes, thus ensuring significant time and money gains. In Portugal, EPP replaced paper-based pre-contractual procedures for communication and processing based on information technologies and systems. Interested in this phenomenon, the authors of this paper structured the TrivPlat project, a tool of free access for monitoring, managing and evaluating electronic public procurement. This paper aims to present the TrivPlat project and its contributions to the discussion about additional efforts needed to be implemented in order to efficiently promote a more transparent and accountable governance, in the defense of public interest.

Eco-efficient mortars with incorporation of phase change materials

Nowadays, the construction is one of the main European sectors responsible for the high levels of energy consumption and raw material extraction. Increasingly, the energy consumption from renewable sources and industrial waste reuse are the only ways to minimize these environmental and societal problems. Simultaneous incorporation of phase change materials and fly ash in the mortars increases the energy efficiency and decreases the waste materials landfilled. The development of mortars with phase change materials and fly ash incorporation contributes to a significant improvement of the building comfort parameters and the environmental quality. The phase change materials possess the capability to normalize the temperature flux inside the buildings, using the solar energy as resource. The main purposes of this study were the physical, mechanical, and thermal characterization of mortars with phase change materials and fly ash incorporation. It was concluded that the phase change materials and fly ash simultaneous incorporation leads to homogeneous and suitable mortars with increased thermal behavior compared with the phase change material addition alone.