Characterization tests for insulation boards made from corn cob and natural glues

In recent years there has been a growing interest in developing news solutions for more ecologic and efficient construction, including natural, renewable and local materials, thus contributing in the search for more efficient, economic and environmentally friendly construction. Several authors have assessed the possibility of using various agricultural sub products or wastes, as part of the effort of the scientific community to find alternative and more ecologic construction materials. Corn cob is an agricultural waste from a very important worldwide crop. Natural glues are made from natural materials, non-mineral, that can be used as such or after some modifications to achieve the behaviour and performance required. Two examples of these natural glues are casein and wheat flour-based glues that were used in the present study. Boards with different compositions were manufactured, having as variables the type of glue, the dimension of the corn cob particles and the features of the pressing process. The tests boards were characterized with physical and mechanical tests, such as thermal conductivity (λ) with a ISOMET 2104 and 60 mm diameter contact probe, density (ρ) based on EN 1602:2013, surface hardness (SH) with a PCE Shore A durometer, surface resistance (SR) with a PROCEQ PT pendular sclerometer, bending behaviour (σ) based on EN 12089:2013, compression behaviour (σ10) based on EN 826:2013 and resilience (R) based on EN 1094-1:2008, with a Zwick Rowell bending equipment with 2 kN and 50 kN load cells (Fig. 1), dynamic modulus of elasticity (Ed) with a Zeus Resonance Meter equipment (Fig. 5) based on NP EN 14146:2006 and water vapour permeability (δ) based on EN 12086:2013. The various boards produced were characterized according to the tests and the ones with the best results were C8_c8 (casein glue, grain size 2,38-4,76 mm, cold pressing for 8 hours), C8_c4 (casein glue, grain size 2,38-4,76 mm, cold pressing for 4 hours), F8_h0.5 (wheat flour glue, grain size 2,38-4,76 mm, hot pressing for 0,5 hours), FEV8_h0.5 (wheat flour, egg white and vinegar glue, grain size 2,38-4,76 mm, hot pressing for 0,5 hours) and FEVH68_c4 (wheat flour, egg white, vinegar and 6 g of sodium hydroxide glue, grain size 2,38-4,76 mm, cold pressing for 4 hours). Taking into account the various boards produced and respective test results the type of glue and the pressure and pressing time are very important factors which strongly influence the final product. The results obtained confirmed the initial hypotheses that these boards have potential as a thermal and, eventually, acoustic insulation material, to use as coating or intermediate layer on walls, floors or false ceilings. This type of board has a high mechanical resistance when compared with traditional insulating materials.The integrity of these boards seems to be maintained even in higher humidity environments. However, due to biological susceptibility and sensitivity to water, they would be more adequate for application in dry interior conditions.COST ACTION FP130

Influence of composition on physical performance and bio-susceptibility

This work was supported by Fundação para a Ciência e a Tecnologia (FCT) under DB-HERITAGE project (PTDC/EPH-PAT/4684/2014). The authors also acknowledge the EMBARRO Company for supplying the majority of the mortar materials and are grateful to Antonio Santos Silva, Miguel Teixeira, Sandra Noivo, Teresa Gonçalves and Vitor Silva for the support throughout the testing campaign. The support of COST Actions FP1303 “Performance of biobased building materials” and RILEM Technical Committees TCE, “Testing and Characterisation of Earth-based building materials and elements” and HDB, “Hygrothermal behaviour and Durability of Bio-aggregate based building materials”, are also acknowledged.An experimental campaign was developed to evaluate the properties of earth plastering mortars, not only at the level of workability and physic-mechanical performance but also their susceptibility for biological colonization. A ready-mixed earth mortar and several other mortars formulated with a raw clayish earth were produced. The influence of partial replacement of fine sand by a phase change material (PCM) and the addition of low amounts of oat fibres and hydrated air lime were assessed. The experimental campaign shows that the PCM completely changes the mortar workability, with a decrease on wet density. The addition of PCM and fibres decreases the bulk density and, consequently, increases the porosity of the mortars. The presence of PCM, fibres and air lime decreases the thermal conductivity. Earth mortars are susceptible to mould development, and the fibres or PCM seem to intensify their bio-susceptibility. A low addition of air lime increases pH and inhibits fungal growth though decreasing the mechanical properties. Mortars with PCM, fibres and air lime present a higher surface roughness in comparison to other mortars, including the ready-mixed earth mortar with fibres. Surface roughness was found to be an important factor influencing the level of colonization.authorsversionpublishe

Characterization of agro-wastes to be used as aggregates for eco-efficient insulation boards

PD/BD/150579/2020This work derives from the awareness of the environmental impacts caused by the construction sector. Since building products are one of the main causes of this issue, the incremental use of local natural eco-friendly materials can moderate this problem, guaranteeing lower energy consumption for production and transport. Nowadays, research is increasingly focused on the possibility of using bio-wastes to produce several materials and products such as plasters, bricks, boards, binders and glues. They can secure both more sustainable building practices and contribute to solve the problems of disposal of wastes, another cause of the environmental impacts. The present work focuses on the characterization of some bio-wastes to assess their viability as aggregates for eco-efficient insulation boards. Knowing the properties of the raw materials allows making a more conscious choice of composite formulations according to the final requirements of the boards. For this reason, the bio-wastes from agricultural practices (agro-wastes) were studied individually. To evaluate their properties, the analysis was carried out according to RILEM Technical Committee 236-BBM, “Bio-aggregate-based building Materials” document, past literature studies and European Standards. The considered properties were loose bulk density, grain size distribution and thermal conductivity. Four agro-wastes were chosen: spent coffee grounds, grapes press waste, olives press waste and hazelnut shells. Maritime pine (Pinus pinaster Ait.) chips were included as control material. They have been considered both for their potential use to produce insulation composites and for their world production, focusing on Euro-Mediterranean countries. This region was chosen taking into account where the future research will be carried out and the advantages of employing local materials. In addition, buildings of Euro-Mediterranean countries have historically low insulation performance due to the mild climate; however, climate change and other factors have led to the recognition by the users of some periods of poor indoor hygrothermal comfort. The bibliographic research allowed identifying a gap as concerns the characterization of these agro-wastes. Both the testing methods and the properties of the considered materials are presented and discussed. In addition, the obtained results are compared with the ones of already studied materials, such as rice husk, hemp shiv and cork. Results show that the chosen materials do not have excellent insulating properties if considered individually but may probably be used to produce eco-efficient boards. The combination of them with other materials could guarantee building composites with good thermal insulation performances. The spent coffee ground differs greatly from the other bio-wastes and it seems to be more appropriate as a fine aggregate. Future research will deepen these studies and develop composites having adequate characteristics as insulation boards.publishersversionpublishe

MOTIVAÇÃO E SATISFAÇÃO NO TRABALHO NA ADMINISTRAÇÃO PÚBLICA - UM ESTUDO DE CASO

Ao longo dos tempos temos verificado que o Estado desempenhou diferentes papéis, sendo nalgumas fases mais ou menos interventivo, noutras mais ou menos social. Quando existe uma recessão económica há tendência para a introdução de reformas profundas. Tais reformas, com algumas características semelhantes, estão baseadas na Nova Gestão Pública, onde as questões gestionárias e manageriais estão presentes. O processo competitivo deixa de ser exclusivo do sector privado passando também para o Estado; a eficiência e a qualidade dos serviços passa a ser um tema dominante da agenda política. Todo o processo de mudança é resultado da acção humana e necessita, por isso, da colaboração dos recursos humanos para ser concretizado com sucesso. Uma boa gestão dos recursos humanos pode potenciar o aumento da eficiência, da eficácia e da qualidade dos serviços públicos. O sucesso de uma organização depende de muitos factores, entre os quais a satisfação dos seus colaboradores; se estes estiverem satisfeitos há uma “real” possibilidade de sucesso para a organização. Neste contexto definimos como objectivo principal do nosso trabalho o estudo do nível da satisfação num contexto específico de trabalho – Instituto Politécnico da Guarda. A escolha deste estudo prende-se com dois motivos: por um lado compreender e testar em que medida alguns factores contribuem para a satisfação no trabalho, nomeadamente factores pessoais como género, idade e habilitações literárias; e factores situacionais como o tempo de serviço, vínculo, categoria e vencimento; e, avaliar o contributo dos factores organizacionais (condições de trabalho, sistemas de gestão, carreira e competências, conteúdo do trabalho e relações humanas) na satisfação profissional dos trabalhadores do Instituto Politécnico da Guarda

Development of a penetration test for timber impregnation products for use in old buildings

This paper studies the application of commercial biocides to old maritime pine timber structures (Pinus pinaster Ait.) that have previously been impregnated with other products. A method was developed in the laboratory to be used in situ to determine the impregnation depth achieved by a new generation biocide product applied to timber from an old building. This timber had once been treated with an unknown product difficult to characterize without extensive analysis. The test was initially developed in laboratory conditions and later tested on elements of the roof structure of an 18th century building. In both cases the results were promising and mutually consistent with penetration depths for some treatments reaching 2.0 cm. The application in situ proved the tests viability and simplicity of execution giving a clear indication on the feasibility of possible re-treatments

a systematic review of observational studies

publishersversionpublishe

Comparison between heat treated sapwood and heartwood from Pinus pinaster

Sapwood and heartwood samples of Pinus pinaster were treated in an oven at 190ºC and 200ºC for 2-6h. Dimensional stability, measured as Anti Shrinking Efficiency (ASE) between 0% and 65% relative humidity, durability against fungi, mechanical resistance (MOE and MOR), hardness and chemical composition were determined for treated and untreated sapwood and heartwood. Radial ASE reached 52% for sapwood and 50% for heartwood while tangential ASE reached 50% and 40% respectively. MOE increased slightly at the beginning of the treatment decreasing afterwards. No significant differences were found between sapwood and heartwood. MOR decreased by 50% and 30% for sapwood and heartwood respectively. A significant increase in durability against Rhodonia placenta was found for both heartwood and sapwood at the higher temperature and for heartwood only at 190º for 4h.info:eu-repo/semantics/publishedVersio

State of the art of industrial wood protection in Portugal

This work intended to give a perspective of industrial wood protection in Portugal. A survey was made of the companies treating wood mainly for use classes 3 and 4 such as autoclave treatments with biocides and wood modification procedures. Currently there are 23 companies with 33 production plants with an autoclave installed for wood preservation by impregnation. There are also two companies producing modified wood by thermal treatment. Most of the plants are located in the central and northern regions of Portugal. The leading preservation chemicals used in Portugal are Tanalith E and Celcure brands. The main wood species used in all companies is Pinus pinaster from local producers. The products commercialized by the treating companies are diverse: pre-fabricated houses, garden furniture and playgrounds, decks, poles, stakes, and sawn wood. Modified wood producers sell mostly decks and cladding. Considerable changes are expected in the next few years due to the requirements of European Directives and the typical constraints of the Portuguese market.info:eu-repo/semantics/publishedVersio

Improvement of termite resistance, dimensional stability and mechanical properties of pine wood by paraffin impregnation

Paraffin has been used as surface protection of wood throughout the ages but its use for impregnation to improve wood resistance to biodegradation is recent. This study determined the main improvements on wood properties with paraffin impregnation. Healthy Pinus pinaster Ait. wood was impregnated with paraffin at different levels using a hot–cold process. Weight gain, equilibrium moisture content and dimensional stability (ASE) at 35 and 65 % relative humidity, termite durability against Reticulitermes grassei (Clément), bending strength, bending stiffness (MOE) and Janka hardness were determined. Density increased from 0.57 to 0.99, ASE ranged between 38–96 % and 16–71 % for 35 and 65 % relative humidity, respectively. Equilibrium moisture content decreased from 9.9 and 12.0 % to 0.8 and 3.6 % for 35 and 65 % relative humidity. Termite durability improved from level 4 to level 3 of attack, and higher termite mortality was found in treated wood (52 % against 17 %). Bending strength (MOR) increased with paraffin weight gain, reaching a 39 % increase. MOE also increased by about 13 % for wood with a weight gain around 80 %. Janka hardness increased significantly reaching about 40 % for wood with 80 % weight gain. Paraffin impregnated wood has improved properties with regard to equilibrium moisture content, dimensional stability and density, bending strength and Janka hardness, and resistance against termites

Comparison between experimental results and design equations of artificially degraded single step joints

In the case of interventions in existing buildings, the assessment of timber elements and joints, such as the Single Step Joint, is a challenge for engineers, especially when timber presents signs of biological degradation. In this context, many roof structures are subject to unnecessary substitutions due to the lack of knowledge about the behaviour of these types of joints, and specially the consequences of eventual biological attacks. This study aims to evaluate the residual shear strength of Single Step Joints artificially degraded by wood boring insects from the Anobiidae family (e.g. Anobium punctatum). To achieve the established objectives, destructive tests were carried out on undamaged (reference level) and artificially degraded Single Step Joint specimens, varying the level of degradation. The results were analysed in terms of degradation level and compared with the results obtained with design equations for this type of joint found in the literature. From the analysis of the results, it was possible to observe the tendency of reduction of the shear strength with the increase of the degradation level.FCT - Fundação para a Ciência e a Tecnologia(PRT/BD/152833/2021