In many events affecting our civil infrastructure, such as contamination or weathering, it is likely that only the surfaces of the affected building materials will be available for non-destructive measurements. In this work, we describe and analyze surface gas permeability measurements on a variety of natural and engineered building materials using two types of relatively new, non-destructive surface permeameters. It is shown that the surface gas permeability measurements correlate well with each other and could provide rapid estimates of macroscopic gas permeability and degradation of materials due to weathering. It is hypothesized that surface permeability can be used to predict macroscopic wicking of water. The results indicated that macroscopic wicking correlated reasonably well with surface permeability measurements of uniform materials with low permeabilities such as sandstones and clay brick.

MSc., Faculty of Science, University of the Witwatersrand, 2011 / A hierarchical non-linear model was developed for the time-dependent shrinkage behaviour of South African concretes, from historical laboratory data. The fit of fifteen growth curve models to the shrinkage-time profiles was evaluated and MCDA was used to identify the best model. The three parameters of the chosen growth curve model were modelled in terms of covariates (relating to concrete raw materials, concrete composition and shrinkage testing conditions) by multivariate multiple regression to produce the WITS model. The model largely conformed to existing knowledge about the factors affecting concrete shrinkage. Published models for concrete shrinkage were compared to the WITS model regarding their predictive ability with respect to the South African data set. The WITS model performed the best across a variety of graphical and numerical goodness-of-fit measures. The importance of the study is two-fold:  The concept of hierarchical non-linear modelling has been applied for the first time to the modelling of the time-dependent properties of concrete.  This is the first comprehensive model to bring together laboratory data on the shrinkage of concrete generated in South Africa over a span of thirty years.

The building and construction sectors are one of the main contributors to the socio-economic development of a country. Globally, these sectors generate around 5% to 10% of national employment and around 5% to 15% of a country's gross domestic product during construction, use and demolition. On the other hand, the sectors consume around 40% of world primary energy, use 30% of raw materials, generate 25% of solid waste, consume 25% of water, and use 12% of land. Furthermore, the sectors account for up to 40% of greenhouse gas (GHG) emissions, mainly from energy use during the life cycle of buildings. This study aims to assess the potential environmental benefits of reusing concrete and ceramic roof tile within the Swedish context in terms of their CO2 emission. Methodology used was a comparative LCA was to quantify the emissions. In order to calculate LCA, OpenLCA 1.7.0 software was used and to evaluate the emissions, LCIA method selected was ReCiPe, midpoint, Hierarchist model, climate change category expressed in GWP 100 years (in kg CO2eq). The FU of the study was a square meter of roof covering for a period of 40 years with potential to extent up to 80 years. A square meter of concrete roof tile weight 40 kg while ceramic 30 kg. The environment impact evaluation considered three product system, single use (cradle to grave), single use covering (cradle to user) and single reuse (user to cradle) within 40 years lifespan. In order to compare LCA of the roof tiles, two scenarios were created, Scenario 1 concrete RT in single use and single reuse whilst Scenario 2 evaluates ceramic RT. The outcomes of both scenarios were communicated through a model single family house. Dalarna’s Villa is located in Dalarna region in Sweden and a storage facility Ta Till Våra was to validate the benefits of reused materials. Comparative LCA revealed that concrete RT in single use released almost 80% more CO2 emissions than ceramic RT and generated 25% more disposable material by weight. The CO2 released by the single use vs. single reuse concrete RT showed higher emissions in the production of the concrete RT than the single reuse, the same occur with ceramic RT. The reuse of the tiles on the same site had an insignificant impact on the environment in both materials. The comparison shows that reuse reduces associated emissions by about 80% in both cases, reusing concrete is more beneficial, as emissions are reduced by 9.95 kg/m2 as opposed to 2.32 kg/m2 at the ceramics. This study reveals the benefit of reusing concrete and ceramic roof tile. In addition, the advantage of building a storage facility to reuse the disposable building materials, reducing the roofing materials ending at the landfill after 40 years. Furthermore, it demonstrated the reduction of CO2 emissions associated with the embodied energy.

Title Chemistry education at secondary schools of civil engineering in the Czech Republic Abstract The goal of this work is to evaluate the chemistry education at secondary schools of civil engineering in the Czech Republic, which provide education of four-year study programs with school leaving exam. At first, question form of data gathering was used at the part of these schools. The general goal was narrowed by analyzing the answers of a questionnaire and the next work was concentrated on creating a study material containing themes of the chemistry of building materials. This material was used during the period of its creation and was modified due to the reactions of the students. The material was then extended with themes of general, inorganic, organic chemistry and biochemistry. The learning material was extended to the form of practice book, which has been used as a main educational tool for the chemistry education. The learning material was evaluated by theoretical methodology and by anonymous questionnaire filled by students. The objective evaluation of the impact of the learning material on the school grades was analyzed through five years. Key words Chemistry of building materials, secondary schools, learning material, workbook.

A radioatividade natural presente em solos, rochas e materiais de construção, devida ao 40K e às séries radioativas do 232Th e 238U é a principal contribuição à exposição externa aos seres humanos. Neste trabalho, determinou-se as concentrações de atividade de 226Ra (da série do 238U), 232Th e 40K presentes em 50 amostras de tintas látex de cor branca comercializadas no Brasil, especificamente, 15 do tipo econômico, 15 do tipo standard, 20 do tipo premium e em uma amostra de dióxido de titânio. As amostras foram seladas e armazenadas por um período mínimo de 30 dias para se alcançar o equilíbrio radioativo secular nas séries do 238U e do 232Th e medidas pela técnica analítica de espectrometria gama de alta resolução. As concentrações de atividade foram calculadas utilizando-se as médias ponderadas pelas incertezas do 214Pb e 214Bi para o 226Ra e médias ponderadas pelas incertezas do 228Ac, 212Pb e 212Bi para o 232Th. A concentração de atividade do 40K foi determinada pela sua transição única de 1460,8 keV. Fatores de autoatenuação gama foram calculados e utilizados para correção da concentração de atividade das amostras com densidade maior que 1,0 g.cm-3. Os índices radiológicos equivalente em rádio (Raeq), índice de concentração de atividade (Iγ), índice de risco à exposição gama interna (Hin), o índice de risco à exposição gama externa (Hex) e a taxa de dose (D) e dose efetiva anual (Def) foram calculados a partir das concentrações de atividade do 226Ra, 232Th e 40K. As concentrações de atividade de 226Ra das tintas variaram entre valores abaixo da atividade mínima detectável e 38,7 Bq.kg-1, as de 232Th variaram entre valores abaixo da atividade mínima detectável e 101,2 Bq.kg-1 e as de 40K variaram entre valores abaixo da atividade mínima detectável e 256 Bq.kg-1. O Raeq variou entre 1,41 Bq.kg-1 e 203 Bq.kg-1, o Iγ variou entre 0,0047 e 0,720, o Hin variou entre 0,0076 e 0,653 e o Hex variou entre 0,0038 e 0,549. A taxa de dose variou de 0,170 nGy.h-1 a 21,3 nGy.h-1 e a dose efetiva anual variou entre 0,83 μSv.a-1 e 104,2 μSv.a-1. Estes resultados mostram que as concentrações de atividades das tintas utilizadas neste estudo estão abaixo dos limites recomendados por Hassan et al. para Raeq (370 Bq.kg-1), pela Comissão Européia para o Iγ (limite de 2 para materiais superficiais) e pela Organização para Cooperação Econômica e Desenvolvimento para Hin e para Hex (ambos com limite de 1), para todas as 50 amostras estudadas, mostrando assim a segurança destas tintas com relação a proteção radiológica. / Natural radioactivity in soils, rocks and construction materials, due to 40K and the natural series of 232Th and 238U, is the main contribution to external exposure in mankind. In this work, activity concentrations of 226Ra (238U serie), 232Th and 40K were determined for 50 white latex wall paints samples, commercialized in Brazil, namely 15 Economic quality samples, 15 Standard quality samples and 20 Premium quality samples and for a single titanium dioxide sample. The samples were tightly sealed and stored for a minimum period of 30 days, to reach the radioactive secular equilibrium from 238U and 232Th series, then measured by high resolution gamma ray spectrometry. The activity concentration was determined using the weighted average concentrations of 214Pb and 214Bi for 226Ra and 228Ac, 212Pb and 212Bi for 232Th. The 40K activity concentration was determined by its single transition of 1460.8 keV. Self attenuation correction factors of the samples whose densities are higher than 1.0 g.cm-3, were determined and used to make the necessary corrections. The radiological indices radium equivalent activity (Raeq), activity concentration index (Iγ), internal exposure risk index (Hin) and external exposure risk index (Hex) and also the absorbed dose rate (D) and annual effective dose (Def) were calculated from the activity concentrations of 226Ra, 232Th and 40K. The activity concentration values for 226Ra ranged from under the minimum detectable activity to 38.7 Bq.kg-1, for 232Th from under the minimum detectable activity to 101.2 Bq.kg-1 and for 40K from under the minimum detectable activity to 256 Bq.kg-1. Raeq ranged from 1.41 Bq.kg-1 to 203 Bq.kg-1, Iγ ranged from 0.0047 to 0.720, Hin from 0.0076 to 0.653 and Hex from 0.0038 to 0.549. The absorbed dose rate ranged from 0.170 nGy.h-1 and 21.3 nGy.h-1 and the annual effective dose ranged from 0.83 μSv and 104.2 μSv. The results show that the activity concentrations of the wall paints studied in this work are below the recommended limits by Hassan et al. for Raeq (370 Bq.kg-1), by European Commission for Iγ (limit of 2 for superficial materials) and by the Organisation for Economic Co-operation and Development for Hin and Hex (both with limit of 1), for all the 50 samples, assuring the safety of these wall paints with respect to radiological protection.

by Ng Cho-yin, Tony, Ha Woon-chun, Mary. / Bibliography : leaf 70 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1982

The United Kingdom published a legally binding document to reduce national greenhouse gas emissions by year 2020 up to 34% against the 1990 levels. This target also fulfils the Europe 2020 strategy of 20% carbon emission reductions by year 2020 (EC, 2010). Emissions due to space heating count for around 60% of the total domestic emissions (DCLG, 2012). The report “Rethinking Construction” published in 1998 emphasised the opportunities to improve the quality and efficiency of the UK construction sector (Egan, 1998). More recently, a framework has been published by the Government to tackle fuel poverty by building more energy efficient homes (DECC, 2015). In terms of energy performance, Passivhaus is recognised as one of the most energy efficient and researched construction standards which requires an exceptionally high-level of insulation and airtightness. Closed-panel timber frames are a relatively new system in UK with an opportunity for growth. These advanced panels are pre-fitted in the factory, reducing the on-site work. However, closed-panel systems present a more complex sole plate fixing detail which can have an undesirable long-term impact on the structural and thermal performance of the building. The work presented in this thesis investigates the structural considerations, racking performance, of timber frame closed panel systems for future building regulations. The thesis underlines the significance of structural stability, serviceability and detailing in relationship with long-term thermal efficiency and airtightness, according to Passivhaus standard. An experimental study was carried out to investigate the structural racking performance of advanced closed panel systems. A comparison was made between the behaviour of the timber frame panels and the analytical PD 6693-1. A set of different wall panel built-ups is presented for optimised Passivhaus design, including thermal bridge-free sole plate details. A timber frame racking software application was developed to optimise the structural design of shear walls. A parametric study was carried out with this tool to generate efficient timber frame wall design tables for different applied racking loads and U-values. The software application also allows for direct specification of robust sole plate base fixings and thermal bridge free details.

Neste trabalho apresenta-se um estudo de caracterizaÃÃo de blocos cerÃmicos estruturais. A finalidade principal à estudar aspectos da microestrutura desses blocos, determinantes no processo de usa ruptura à compressÃo. SÃo utilizados 18 blocos cerÃmicos estruturais, submetidos à compressÃo atà a ruptura. Para a caracterizaÃÃo da microestrutura, retiram-se amostras de blocos especÃficos de acordo com os resultados obtidos nos ensaios de resistÃncia à compressÃo. A observaÃÃo da microestrutura à realizada com a utilizaÃÃo de microscopia Ãtica e de microscopia eletrÃnica de varredura. SÃo tambÃm realizadas anÃlises de composiÃÃo quÃmica atravÃs de EDS âenergy dispersion spectrometryâ. Com a anÃlise dos resultados identifica-se a existÃncia de relaÃÃes fundamentais entre formato e disposiÃÃo dos poros presentes na microestrutura dos blocos e o processo de ruptura à compressÃo. Com base nestas relaÃÃes, propÃe-se um esquema teÃrico para o mecanismo de ruptura dos blocos cerÃmicos estruturais. TambÃm à apresentado um estudo quantitativo da microestrutura (metalografia) dos blocos cerÃmicos estruturais. Adicionalmente sÃo confeccionados prisnas ( dois blocos unidos por uma junta de argamassa) e prismas contrafiados ( formados por um bloco e meio na base e com trÃs fiadas de altura, unidos por juntas verticais e horizontais) com trÃs diferentes traÃos de argamassa. Determina-se para os prismas e para os prismas contrafiados a resistÃncia à compressÃo. SÃo, entÃo, propostas equaÃÃes relacionadas as propriedades medidas para cada um dos elementos ( prismas e prismas contrafiados) estudados. / This paper presents a study of structural characterization of ceramic blocks. The main purpose is to study aspects of the microstructure of these blocks, in the process of determining uses compression rupture. 18 blocks are used structural ceramics subjected to compression up to failure. To characterize the microstructure, withdraw samples of particular blocks in accordance with the results of the tests of resistance to compression. The observation of the microstructure is performed using optical microscopy and scanning electron microscopy. They are also chemical composition analysis using EDS "energy dispersion spectrometry." By analyzing the results identified the existence of relationships between fundamental shape and arrangement of pores present in the microstructure of the blocks and the process of compression rupture. Based on these relationships, it is proposed a conceptual framework for the mechanism of breaking the ceramic block structure. It also presents a quantitative study of the microstructure (metallography) of structural ceramic blocks. Additionally prisnas are made (two blocks joined by a mortar) and contrafiados prisms (formed by a block and a half at the base and with three rows of height, connected by vertical and horizontal joints) with three different traces of mortar. Is determined for the prisms and the prisms contrafiados the compressive strength. Are then proposed equations relating the measured properties for each element (contrafiados prisms and prisms) studied.

A radioatividade natural presente em solos, rochas e materiais de construção, devida ao 40K e às séries radioativas do 232Th e 238U é a principal contribuição à exposição externa aos seres humanos. Neste trabalho, determinou-se as concentrações de atividade de 226Ra (da série do 238U), 232Th e 40K presentes em 50 amostras de tintas látex de cor branca comercializadas no Brasil, especificamente, 15 do tipo econômico, 15 do tipo standard, 20 do tipo premium e em uma amostra de dióxido de titânio. As amostras foram seladas e armazenadas por um período mínimo de 30 dias para se alcançar o equilíbrio radioativo secular nas séries do 238U e do 232Th e medidas pela técnica analítica de espectrometria gama de alta resolução. As concentrações de atividade foram calculadas utilizando-se as médias ponderadas pelas incertezas do 214Pb e 214Bi para o 226Ra e médias ponderadas pelas incertezas do 228Ac, 212Pb e 212Bi para o 232Th. A concentração de atividade do 40K foi determinada pela sua transição única de 1460,8 keV. Fatores de autoatenuação gama foram calculados e utilizados para correção da concentração de atividade das amostras com densidade maior que 1,0 g.cm-3. Os índices radiológicos equivalente em rádio (Raeq), índice de concentração de atividade (Iγ), índice de risco à exposição gama interna (Hin), o índice de risco à exposição gama externa (Hex) e a taxa de dose (D) e dose efetiva anual (Def) foram calculados a partir das concentrações de atividade do 226Ra, 232Th e 40K. As concentrações de atividade de 226Ra das tintas variaram entre valores abaixo da atividade mínima detectável e 38,7 Bq.kg-1, as de 232Th variaram entre valores abaixo da atividade mínima detectável e 101,2 Bq.kg-1 e as de 40K variaram entre valores abaixo da atividade mínima detectável e 256 Bq.kg-1. O Raeq variou entre 1,41 Bq.kg-1 e 203 Bq.kg-1, o Iγ variou entre 0,0047 e 0,720, o Hin variou entre 0,0076 e 0,653 e o Hex variou entre 0,0038 e 0,549. A taxa de dose variou de 0,170 nGy.h-1 a 21,3 nGy.h-1 e a dose efetiva anual variou entre 0,83 μSv.a-1 e 104,2 μSv.a-1. Estes resultados mostram que as concentrações de atividades das tintas utilizadas neste estudo estão abaixo dos limites recomendados por Hassan et al. para Raeq (370 Bq.kg-1), pela Comissão Européia para o Iγ (limite de 2 para materiais superficiais) e pela Organização para Cooperação Econômica e Desenvolvimento para Hin e para Hex (ambos com limite de 1), para todas as 50 amostras estudadas, mostrando assim a segurança destas tintas com relação a proteção radiológica. / Natural radioactivity in soils, rocks and construction materials, due to 40K and the natural series of 232Th and 238U, is the main contribution to external exposure in mankind. In this work, activity concentrations of 226Ra (238U serie), 232Th and 40K were determined for 50 white latex wall paints samples, commercialized in Brazil, namely 15 Economic quality samples, 15 Standard quality samples and 20 Premium quality samples and for a single titanium dioxide sample. The samples were tightly sealed and stored for a minimum period of 30 days, to reach the radioactive secular equilibrium from 238U and 232Th series, then measured by high resolution gamma ray spectrometry. The activity concentration was determined using the weighted average concentrations of 214Pb and 214Bi for 226Ra and 228Ac, 212Pb and 212Bi for 232Th. The 40K activity concentration was determined by its single transition of 1460.8 keV. Self attenuation correction factors of the samples whose densities are higher than 1.0 g.cm-3, were determined and used to make the necessary corrections. The radiological indices radium equivalent activity (Raeq), activity concentration index (Iγ), internal exposure risk index (Hin) and external exposure risk index (Hex) and also the absorbed dose rate (D) and annual effective dose (Def) were calculated from the activity concentrations of 226Ra, 232Th and 40K. The activity concentration values for 226Ra ranged from under the minimum detectable activity to 38.7 Bq.kg-1, for 232Th from under the minimum detectable activity to 101.2 Bq.kg-1 and for 40K from under the minimum detectable activity to 256 Bq.kg-1. Raeq ranged from 1.41 Bq.kg-1 to 203 Bq.kg-1, Iγ ranged from 0.0047 to 0.720, Hin from 0.0076 to 0.653 and Hex from 0.0038 to 0.549. The absorbed dose rate ranged from 0.170 nGy.h-1 and 21.3 nGy.h-1 and the annual effective dose ranged from 0.83 μSv and 104.2 μSv. The results show that the activity concentrations of the wall paints studied in this work are below the recommended limits by Hassan et al. for Raeq (370 Bq.kg-1), by European Commission for Iγ (limit of 2 for superficial materials) and by the Organisation for Economic Co-operation and Development for Hin and Hex (both with limit of 1), for all the 50 samples, assuring the safety of these wall paints with respect to radiological protection.

No description available.