La carbonatation atmosphérique et la pénétration des ions chlorures sont les principales causes du déclenchement de la corrosion des armatures dans les bétons armés. Chacun de ses mécanismes a fait l'objet de nombreuses études dans la bibliographie. Pourtant les études prenant en compte en même temps les deux types d'agression sont rares. Le couplage des deux phénomènes existe cependant. La carbonatation intervient en effet dans tout ouvrage dès le décoffrage et il suffit que cet ouvrage soit aussi par exemple situé à proximité d'eau de mer pour que les embruns apportent des ions chlorures dans le matériau. L'objectif de cette thèse a été de quantifier les différentes phases de la matrice cimentaire et ses capacités de fixation des ions chlorures par le biais d'isothermes d'interactions pour des matériaux sains et carbonatés. Ces isothermes d'interactions obtenues notamment par la méthode des équilibres ont permis de voir que les matrices partiellement ou totalement carbonatées fixaient moins d'ions chlorures que les matrices saines. L'utilisation de moyens complémentaires d'analyses tels que l'analyse thermogravimétrique (ATG), la diffraction des rayons X (DRX) et la résonance magnétique nucléaire (RMN) a permis de mieux comprendre cette perte de fixation. Une diminution des sels de Friedel et des chlorures fixés par les C-S-H a été ainsi mise en évidence dans les matériaux carbonatés. Ces diminutions qui on été quantifiées sont attribuées à une modification sous carbonatation des phases capables de fixer les ions chlorures (phases aluminates, sulfo-aluminates et C-S-H). Des différences au niveau du réseau poreux ont été également mises en évidence par la porosimétrie par intrusion de mercure (diminution de la macroporosité et de la connectivité en général pour les matrices carbonatées par formation de CaCO3). L'objectif a été aussi de corréler toutes ces modifications observées avec les propriétés de transport des ions qui ont été obtenues par des tests de diffusion et migration des ions chlorures (et/ou sulfates) ainsi que des mesures de résistivité électrique. Les résultats expérimentaux ont montré que le coefficient de diffusion apparent est plus grand dans les matériaux carbonatés. Certaines expériences de diffusion faites en présence à la fois d'ions chlorures et sulfates ont aussi montré la concurrence de ces deux ions pour se fixer à la matrice cimentaire. Les matériaux cimentaires testés (bétons et pâtes) ont été formulés sans ou avec additions minérales (métakaolin, cendres volantes, laitier) et les propriétés de ces matériaux ont été observées à différents âges / Carbonation and chloride ingress are the main causes of reinforced concrete degradation. A lot of studies describe these two phenomena separately but only few studies state a possible coupling. However, the coupling of both phenomena exists. The corrosion of reinforcement due to chloride ions occurs more often in marine environments or in the presence of deicing salts while carbonation occurs systematically, in a more or less high degree depending on environmental conditions (humidity, temperature…). The aim of this thesis was to quantify the different phases of the cement matrix and its chloride binding by means of chloride binding isotherms for carbonated and non-carbonated cement based materials. These chloride binding isotherms, obtained by the equilibrium method, showed that the partially or totally carbonated cement matrix are bound fewer chlorides than the non carbonated ones. Complementary techniques such as the thermogravimetry (TGA), the X-rays diffraction (XRD) and the nuclear magnetic resonance (NMR) analyses were used and allowed to understand why this binding decrease occurs. A decrease of Friedel's salt and chlorides bound in the C-S-H was showed in the carbonated materials. These decreases were quantified and are due to a modification of the phases containing chloride (such as aluminates, sulfo-aluminates and C-S-H phases) during carbonation process. The porous network, was observed by mercury intrusion porosimetry (MIP), was also modified (decrease of the macroporosity and the connectivity for carbonated cement matrix due to formation of calcium carbonate). The other aim was to correlate all these modifications with the ions transport properties. Chloride diffusion and migration tests (with or without sulfates) were obtained as well as the measurements of electric resistivity. The experimental results showed that the apparent chloride diffusion coefficient is higher in the carbonated cement materials. Some diffusion tests were performed in presence of both chlorides and sulfates, which showed the competition of these two ions to bind on the cement matrix. Cement materials (concrete and cement paste) were designed without or with supplementary cementing materials (metakaolin, fly ash, slag) and the properties of these materials were followed at different curing time

Ao longo da história da humanidade, a visão de progresso prevalente se expressa pelo crescente domínio e transformação da natureza. De acordo com este paradigma, os recursos naturais são vistos como ilimitados. Isto pode justificar a falta de preocupação com os resíduos gerados durante a produção e ao final da vida útil dos produtos, características de um modelo linear de produção. No contexto atual de preocupação com a degradação ambiental e o esgotamento das reservas naturais muitas iniciativas foram implementadas no sentido de conscientizar os setores produtivos da economia e os órgãos governamentais dos países da necessidade de mudanças. A indústria da construção civil é o maior consumidor de recursos naturais de qualquer economia e um grande gerador de resíduos. O desenvolvimento de produtos, processos e serviços menos agressivos ao meio ambiente e à saúde humana é um desafio para as nações que buscam o desenvolvimento sustentável e encontram na indústria da construção civil um suporte para as mudanças necessárias. Dentro desta realidade, existe a necessidade do desenvolvimento de ferramentas computacionais que auxiliem na seleção de produtos mais sustentáveis na construção civil. Em alguns países, softwares estão sendo desenvolvidos para servirem como ferramenta de apoio à tomada de decisão na busca por produtos e serviços mais sustentáveis. Alguns destes, como o Building for Environmental and Economic Sustainability versão 3.0 (BEES 3.0), são fundamentados na Análise de Ciclo de Vida (ACV). Este é um procedimento sistemático para mensurar e avaliar os impactos que um produto ou material causa no meio ambiente e sobre a saúde humana, desde a sua produção até a disposição final. O BEES é um programa de apoio à decisão desenvolvido pela SETAC (Society of Environmental Toxicology and Chemistry), para ser utilizado na escolha de produtos e materiais da construção e em programas de certificação ambiental de produtos e edifícios. O mesmo foi desenvolvido nos Estados Unidos, por isso não se pode ter certeza de sua aplicabilidade direta para as condições de países com realidades tão diferentes como é o caso do Brasil. O presente estudo buscou verificar a possibilidade de gerar dados confiáveis sobre os impactos causados durante o ciclo de vida das estruturas de concreto armado e comparar os resultados com os gerados pelo software BEES 3.0, verificando a validade de suas premissas para a realidade brasileira. Os resultados indicam que softwares como o BEES podem ser importantes para a análise de impactos ambientais, mas necessitam ser adaptados para a realidade brasileira. È fundamental, ainda, coletar dados adequados sobre as práticas produtivas usadas no Brasil para alimentar este tipo de análise. A análise de três tipos de concretos, com e sem adições, usando as premissas do programa, evidencia que é possível projetar materiais de construção com menor impacto ambiental. / Along the evolution of mankind, the dominating vision of progress has often been represented by the control and transformation of nature. According to this paradigm, natural resources are seen as limitless. This can justify the historical lack of concern regarding the production of waste during the manufacturing and use of goods, a typical stance of the linear model of production that prevail until almost the end of the XXth century. Since then, a rising awareness of the importance of environmental values has brought along a new concern about the degradation of natural environments and the exhaustion of natural resources. In tandem, many initiatives started to be implemented to convince private and public sectors of the economy of the need for changes. The development of new products, processes and services, less aggressive to the environment and the public health, is a challenge for all nations that are trying to pursue a more sustainable development path. The civil construction industry has an important role in this scenario, because it is the biggest consumer of natural resources of any economy and a great source of residues. Given the complexity of the issue, it is useful to develop computational tools to assist in the selection of “greener” products. Various countries are developing software aids that help making more informed decisions regarding sustainable practices. One of them is the Building for Environmental and Economic Sustainability (BEES), developed for the SETAC (Society of Environmental Toxicology and Chemistry) in the US, to be used in the selection of products and materials for construction and in programs of environmental certification of products and buildings. It is based on a Life Cycle Assessment (LCA), a systematic procedure used to measure the impacts that a product or material causes in the environment or on the human being’s health, from its production up to final disposal. Although environmental problems are normally global and not limited by political barriers, differences between production practices, costs and general policy values among Brazil and the US gives rise to caution in adopting the BEES software in Brazil without a previous evaluation and adaptation to the local reality. To help in this sense, this study investigated how results generated with version 3.0 of the BEES software would compare with values derived from a direct analysis of the environmental impact of the production of a reinforced concrete beam. The analysis of beams produced with three types of concrete, with and without the addition of supplementary cementing materials, provided evidence that it is possible, in both cases, to identify key environmental costs and project structures to obtain a smaller environmental impact. The study indicated that software such as BEES can be quite useful in the process of identifying and checking better production practices. It is necessary, however, to adapt them to the local reality and to start collecting reliable data about the environmental costs of production practices used in Brazil to allow them to work properly.

Ao longo da história da humanidade, a visão de progresso prevalente se expressa pelo crescente domínio e transformação da natureza. De acordo com este paradigma, os recursos naturais são vistos como ilimitados. Isto pode justificar a falta de preocupação com os resíduos gerados durante a produção e ao final da vida útil dos produtos, características de um modelo linear de produção. No contexto atual de preocupação com a degradação ambiental e o esgotamento das reservas naturais muitas iniciativas foram implementadas no sentido de conscientizar os setores produtivos da economia e os órgãos governamentais dos países da necessidade de mudanças. A indústria da construção civil é o maior consumidor de recursos naturais de qualquer economia e um grande gerador de resíduos. O desenvolvimento de produtos, processos e serviços menos agressivos ao meio ambiente e à saúde humana é um desafio para as nações que buscam o desenvolvimento sustentável e encontram na indústria da construção civil um suporte para as mudanças necessárias. Dentro desta realidade, existe a necessidade do desenvolvimento de ferramentas computacionais que auxiliem na seleção de produtos mais sustentáveis na construção civil. Em alguns países, softwares estão sendo desenvolvidos para servirem como ferramenta de apoio à tomada de decisão na busca por produtos e serviços mais sustentáveis. Alguns destes, como o Building for Environmental and Economic Sustainability versão 3.0 (BEES 3.0), são fundamentados na Análise de Ciclo de Vida (ACV). Este é um procedimento sistemático para mensurar e avaliar os impactos que um produto ou material causa no meio ambiente e sobre a saúde humana, desde a sua produção até a disposição final. O BEES é um programa de apoio à decisão desenvolvido pela SETAC (Society of Environmental Toxicology and Chemistry), para ser utilizado na escolha de produtos e materiais da construção e em programas de certificação ambiental de produtos e edifícios. O mesmo foi desenvolvido nos Estados Unidos, por isso não se pode ter certeza de sua aplicabilidade direta para as condições de países com realidades tão diferentes como é o caso do Brasil. O presente estudo buscou verificar a possibilidade de gerar dados confiáveis sobre os impactos causados durante o ciclo de vida das estruturas de concreto armado e comparar os resultados com os gerados pelo software BEES 3.0, verificando a validade de suas premissas para a realidade brasileira. Os resultados indicam que softwares como o BEES podem ser importantes para a análise de impactos ambientais, mas necessitam ser adaptados para a realidade brasileira. È fundamental, ainda, coletar dados adequados sobre as práticas produtivas usadas no Brasil para alimentar este tipo de análise. A análise de três tipos de concretos, com e sem adições, usando as premissas do programa, evidencia que é possível projetar materiais de construção com menor impacto ambiental. / Along the evolution of mankind, the dominating vision of progress has often been represented by the control and transformation of nature. According to this paradigm, natural resources are seen as limitless. This can justify the historical lack of concern regarding the production of waste during the manufacturing and use of goods, a typical stance of the linear model of production that prevail until almost the end of the XXth century. Since then, a rising awareness of the importance of environmental values has brought along a new concern about the degradation of natural environments and the exhaustion of natural resources. In tandem, many initiatives started to be implemented to convince private and public sectors of the economy of the need for changes. The development of new products, processes and services, less aggressive to the environment and the public health, is a challenge for all nations that are trying to pursue a more sustainable development path. The civil construction industry has an important role in this scenario, because it is the biggest consumer of natural resources of any economy and a great source of residues. Given the complexity of the issue, it is useful to develop computational tools to assist in the selection of “greener” products. Various countries are developing software aids that help making more informed decisions regarding sustainable practices. One of them is the Building for Environmental and Economic Sustainability (BEES), developed for the SETAC (Society of Environmental Toxicology and Chemistry) in the US, to be used in the selection of products and materials for construction and in programs of environmental certification of products and buildings. It is based on a Life Cycle Assessment (LCA), a systematic procedure used to measure the impacts that a product or material causes in the environment or on the human being’s health, from its production up to final disposal. Although environmental problems are normally global and not limited by political barriers, differences between production practices, costs and general policy values among Brazil and the US gives rise to caution in adopting the BEES software in Brazil without a previous evaluation and adaptation to the local reality. To help in this sense, this study investigated how results generated with version 3.0 of the BEES software would compare with values derived from a direct analysis of the environmental impact of the production of a reinforced concrete beam. The analysis of beams produced with three types of concrete, with and without the addition of supplementary cementing materials, provided evidence that it is possible, in both cases, to identify key environmental costs and project structures to obtain a smaller environmental impact. The study indicated that software such as BEES can be quite useful in the process of identifying and checking better production practices. It is necessary, however, to adapt them to the local reality and to start collecting reliable data about the environmental costs of production practices used in Brazil to allow them to work properly.

Ao longo da história da humanidade, a visão de progresso prevalente se expressa pelo crescente domínio e transformação da natureza. De acordo com este paradigma, os recursos naturais são vistos como ilimitados. Isto pode justificar a falta de preocupação com os resíduos gerados durante a produção e ao final da vida útil dos produtos, características de um modelo linear de produção. No contexto atual de preocupação com a degradação ambiental e o esgotamento das reservas naturais muitas iniciativas foram implementadas no sentido de conscientizar os setores produtivos da economia e os órgãos governamentais dos países da necessidade de mudanças. A indústria da construção civil é o maior consumidor de recursos naturais de qualquer economia e um grande gerador de resíduos. O desenvolvimento de produtos, processos e serviços menos agressivos ao meio ambiente e à saúde humana é um desafio para as nações que buscam o desenvolvimento sustentável e encontram na indústria da construção civil um suporte para as mudanças necessárias. Dentro desta realidade, existe a necessidade do desenvolvimento de ferramentas computacionais que auxiliem na seleção de produtos mais sustentáveis na construção civil. Em alguns países, softwares estão sendo desenvolvidos para servirem como ferramenta de apoio à tomada de decisão na busca por produtos e serviços mais sustentáveis. Alguns destes, como o Building for Environmental and Economic Sustainability versão 3.0 (BEES 3.0), são fundamentados na Análise de Ciclo de Vida (ACV). Este é um procedimento sistemático para mensurar e avaliar os impactos que um produto ou material causa no meio ambiente e sobre a saúde humana, desde a sua produção até a disposição final. O BEES é um programa de apoio à decisão desenvolvido pela SETAC (Society of Environmental Toxicology and Chemistry), para ser utilizado na escolha de produtos e materiais da construção e em programas de certificação ambiental de produtos e edifícios. O mesmo foi desenvolvido nos Estados Unidos, por isso não se pode ter certeza de sua aplicabilidade direta para as condições de países com realidades tão diferentes como é o caso do Brasil. O presente estudo buscou verificar a possibilidade de gerar dados confiáveis sobre os impactos causados durante o ciclo de vida das estruturas de concreto armado e comparar os resultados com os gerados pelo software BEES 3.0, verificando a validade de suas premissas para a realidade brasileira. Os resultados indicam que softwares como o BEES podem ser importantes para a análise de impactos ambientais, mas necessitam ser adaptados para a realidade brasileira. È fundamental, ainda, coletar dados adequados sobre as práticas produtivas usadas no Brasil para alimentar este tipo de análise. A análise de três tipos de concretos, com e sem adições, usando as premissas do programa, evidencia que é possível projetar materiais de construção com menor impacto ambiental. / Along the evolution of mankind, the dominating vision of progress has often been represented by the control and transformation of nature. According to this paradigm, natural resources are seen as limitless. This can justify the historical lack of concern regarding the production of waste during the manufacturing and use of goods, a typical stance of the linear model of production that prevail until almost the end of the XXth century. Since then, a rising awareness of the importance of environmental values has brought along a new concern about the degradation of natural environments and the exhaustion of natural resources. In tandem, many initiatives started to be implemented to convince private and public sectors of the economy of the need for changes. The development of new products, processes and services, less aggressive to the environment and the public health, is a challenge for all nations that are trying to pursue a more sustainable development path. The civil construction industry has an important role in this scenario, because it is the biggest consumer of natural resources of any economy and a great source of residues. Given the complexity of the issue, it is useful to develop computational tools to assist in the selection of “greener” products. Various countries are developing software aids that help making more informed decisions regarding sustainable practices. One of them is the Building for Environmental and Economic Sustainability (BEES), developed for the SETAC (Society of Environmental Toxicology and Chemistry) in the US, to be used in the selection of products and materials for construction and in programs of environmental certification of products and buildings. It is based on a Life Cycle Assessment (LCA), a systematic procedure used to measure the impacts that a product or material causes in the environment or on the human being’s health, from its production up to final disposal. Although environmental problems are normally global and not limited by political barriers, differences between production practices, costs and general policy values among Brazil and the US gives rise to caution in adopting the BEES software in Brazil without a previous evaluation and adaptation to the local reality. To help in this sense, this study investigated how results generated with version 3.0 of the BEES software would compare with values derived from a direct analysis of the environmental impact of the production of a reinforced concrete beam. The analysis of beams produced with three types of concrete, with and without the addition of supplementary cementing materials, provided evidence that it is possible, in both cases, to identify key environmental costs and project structures to obtain a smaller environmental impact. The study indicated that software such as BEES can be quite useful in the process of identifying and checking better production practices. It is necessary, however, to adapt them to the local reality and to start collecting reliable data about the environmental costs of production practices used in Brazil to allow them to work properly.

Alkali-Aggregate Reaction (AAR) is one of the most harmful distress mechanisms affecting the serviceability and durability of concrete critical infrastructure worldwide. Over the past decades, several approaches and recommendations have been developed to assess the potential reactivity of aggregates in the laboratory and the efficiency of preventive measures (e.g., supplementary cementing materials – SCMs) to mitigate ASR in the field. Yet, recent findings suggest that the appropriate use of SCMs “only” delayed and does not entirely prevent ASR occurrence. Moreover, once ASR starts in the field, there is no “universal” solution that should be applied in various cases, and each situation should be evaluated as “unique”. Nevertheless, artificially triggering healing agents have been studied in the late years, thus presenting an interesting “physical” solution to reduce the ingress of water and recover damaged concrete elements, which could present an interesting solution for durability-related distress due to ASR. This Ph.D. project focuses on detailed laboratory investigations aiming first to understand the self-healing process of concrete (i.e., by the natural or engineered process). Then, its further influence on ASR-induced expansion and deterioration, either applied internally or externally to the concrete. To achieve this goal, concrete mixtures presenting a wide range of binder compositions, using distinct types of chemical admixtures (e.g., crystalline self-healing), and incorporating five different types/nature of highly reactive aggregates (i.e., coarse and fine) were combined to manufactured concrete specimens in the laboratory. Otherwise, in aging specimens, concrete samples were designed only with GU-cement as the binder material but incorporated two different types/nature of highly reactive aggregates. Then, the samples were exposed to ASR-induced development until they reached pre-determined expansion levels, in which a wide range of sealers and coating materials were applied on the surface of the affected specimens. Mechanical (i.e., stiffness damage test, modulus of elasticity, micro indentation, shear and compressive strengths) and microscopic (damage rating index and scanning electron microscopy) tests were performed on samples at different ages (up to two years of accelerated ASR development). The results show that besides changing AAR-kinetics, the different binder compositions or the chemical admixtures could modify the distress mechanism due to AAR. The addition of crystalline healing agents or their combination with SCMs in concrete not only delayed the development of inner damage but significantly lowered the compressive strength loss at equivalent expansion amplitudes than control specimens. Moreover, the combination of different binder materials modified the chemical and mechanical properties of the ASR-gel, changing its swelling properties and the further damage development in concrete. On the other hand, the wide range of surface treatments used were not able to alter ASR distress mechanism; yet, they changed ASR-kinetics. Moreover, their effectiveness to slower the reaction shows to be significantly influenced by the damage degree to which the surface treatment is applied. Finally, a comprehensive framework enabling the optimized selection of raw materials to prevent or mitigate ASR development is proposed.

The construction industry is the largest consumer of materials in our society. Approximately 40% of all materials used are related to this section of the industry. Equivalent is the impact of the sector’s activities to the environment in terms of non-renewable energy sources (grey energy), gas emissions (mainly CO2), solid waste, etc. With concrete being the most widely used construction material (second only to water in total volumes consumed annually by society) and cement being the essential “glue” in concrete, emphasis should be placed on investigating and enforcing appropriate ways, methodologies and policies, to make cement manufacturing and the construction industry in general a more environmental friendly sector. At the same time, by considering, at one hand the significant amount of research and breakthroughs achieved on structural materials and design, as well as the level of sophistication of the modern European Standards and structural codes, and on the other hand, the increasing cases of premature deterioration of concrete structures, particular emphasis should also be placed on safeguarding the service life of reinforced concrete structures (in addition to tackling their environmental burden). That is why it is very important to introduce the sustainable way of thinking and the concept of industrial ecology on the preliminary design stages of a structure, on the material selection process and on the service life estimation stage, in achieving a robust durable reinforced concrete (RC) structure (for a given service life) with the minimum environmental burden. Thus, the main objective of the present Thesis is to focus on identifying and quantifying a structured framework of the appropriate methodologies in formulating an Integrated Design Process (IDP) for the design of durable and sustainable structures at the minimum environmental and economical cost (without compromising issues of structural safety) and also in identifying and demonstrating ways of industrial ecology for the sustainable development of the cement and construction industry. The present Thesis contributes to the evaluation of the environmental cost of each component of concrete and to provide the best possible mix design configuration (by means of a holistic analytical software tool) in terms of low environmental cost, as well as, to assess this proposed configuration in terms of strength and durability requirements. Overall, it has to be emphasized that through the present Thesis a new indicator is proposed for design purposes: the environmental cost, which can be added to the existing strength, durability and economic cost indicators towards an integrated design optimization of concrete structures. Finally, it is concluded that the incorporation of new Supplementary Cementing Materials (SCM), as biomass ashes and especially Rice Husk Ash (RHA), offers new perspectives for decreasing the environmental cost of constructions. / Η κατασκευαστική βιομηχανία αποτελεί τον μεγαλύτερο καταναλωτή υλικών στην κοινωνία μας. Περίπου το 40% όλων των υλικών που χρησιμοποιούνται σχετίζονται με αυτόν τον τομέα της βιομηχανίας. Αντίστοιχο αντίκτυπο έχουν και οι δραστηριότητες του τομέα στο περιβάλλον σε ότι αφορά τις μη ανανεώσιμες πηγές ενέργειας («γκρίζα» ενέργεια), αέριες εκπομπές (κυρίωςCO2 ), στερεά απόβλητα, κλπ. Δεδομένου ότι το σκυρόδεμα αποτελεί το πιο ευρέως χρησιμοποιούμενο δομικό υλικό (δεύτερο μετά το νερό σε συνολικούς όγκους που καταναλώνονται ετησίως από την κοινωνία) και ότι το τσιμέντο είναι η απαραίτητη «κόλλα» στο σκυρόδεμα, έμφαση πρέπει να δοθεί στη διερεύνηση και επιβολή κατάλληλων τρόπων, μεθοδολογιών και πολιτικών για τη μετατροπή της τσιμεντοβιομηχανίας και της κατασκευαστικής βιομηχανίας σε έναν γενικά περισσότερο περιβαλλοντικά φιλικό τομέα. Ταυτόχρονα, λαμβάνοντας υπόψη από τη μια μεριά τη σημαντική ποσότητα έρευνας και τα επιτεύγματα σχετικά με τα δομικά υλικά και τον σχεδιασμό, και επιπλέον το επίπεδο της επιτήδευσης των σύγχρονων Ευρωπαϊκών Προτύπων και κατασκευαστικών κανονισμών, και από την άλλη μεριά τις αυξανόμενες περιπτώσεις της πρώιμης φθοράς των κατασκευών από σκυρόδεμα, ιδιαίτερη έμφαση θα πρέπει να δοθεί στη διασφάλιση της διάρκειας ζωής των κατασκευών οπλισμένου σκυροδέματος (σε συνδυασμό με την αντιμετώπιση της περιβαλλοντικής τους επιβάρυνσης). Για το λόγο αυτό είναι ιδιαίτερα σημαντική η εισαγωγή του βιώσιμου τρόπου σκέψης και της έννοιας της βιομηχανικής οικολογίας στα προκαταρκτικά στάδια σχεδιασμού μιας κατασκευής, κατά τη διαδικασία επιλογής υλικών και κατά το στάδιο εκτίμησης της διάρκειας ζωής, ώστε να επιτευχθεί μια εύρωστη, ανθεκτική κατασκευή οπλισμένου σκυροδέματος (για δεδομένη διάρκεια ζωής) με την ελάχιστη περιβαλλοντική επιβάρυνση. Συνεπώς, ο κύριος στόχος της παρούσας Διατριβής είναι να επικεντρωθεί στον εντοπισμό και ποσοτικοποίηση ενός δομημένου προτύπου κατάλληλων μεθοδολογιών για τον σχηματισμό μιας Ενοποιημένης Διαδικασίας Σχεδιασμού για τον σχεδιασμό ανθεκτικών και βιώσιμων κατασκευών με το ελάχιστο περιβαλλοντικό και οικονομικό κόστος (χωρίς συμβιβασμούς σε θέματα που άπτονται της κατασκευαστικής ασφάλειας) και επίσης για την αναγνώριση και επίδειξη τρόπων βιομηχανικής οικολογίας για την βιώσιμη ανάπτυξη της βιομηχανίας τσιμέντου και σκυροδέματος. Η παρούσα Διατριβή συνεισφέρει στην αξιολόγηση του περιβαλλοντικού κόστους κάθε συστατικού του σκυροδέματος αλλά και στην παροχή ενός καλύτερου δυνατού σχεδιασμού σύνθεσης σκυροδέματος (μέσω ενός ολιστικού αναλυτικού λογισμικού) υπό όρους χαμηλού περιβαλλοντικού κόστους, καθώς και στο να αξιολογήσει την προτεινόμενη σύνθεση υπό όρους αντοχής και απαιτήσεων ανθεκτικότητας. Συνολικά, πρέπει να τονισθεί ότι στη παρούσα Διατριβή προτείνεται για πρώτη φορά ένας νέος δείκτης για σκοπούς σχεδιασμού: το περιβαλλοντικό κόστος, το οποίο μπορεί να προστεθεί στους υπάρχοντες δείκτες αντοχής, ανθεκτικότητας και οικονομικού κόστους προς μια ολοκληρωμένη αριστοποίηση σχεδιασμού κατασκευών από σκυρόδεμα. Τέλος, προκύπτει το συμπέρασμα ότι η ενσωμάτωση νέων συμπληρωματικών υδραυλικών υλικών (SCM: Supplementary Cementing Materials), όπως οι τέφρες βιομάζας και ειδικά η τέφρα φλοιού ρυζιού (RHA: Rice Husk Ash), προσφέρει νέες προοπτικές για τη μείωση του περιβαλλοντικού κόστους σκυροδέματος.