| Περίληψη: | 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.
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