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The Industrial Revolution in the middle of the 18th century determined mankind’s destiny. The mass production of goods increased the population at an accelerated rate, and, consequently, mankind is facing the risk of natural resources and energy depletion. The greatest challenge to mankind in this century is to ensure the sustainability of the “inhabitants” of the Earth. The basis of mankind’s social and economic activities is infrastructure and buildings. As a result, the construction industry has a far greater influence on the sustainability of mankind and the Earth. Unfortunately, the construction industry has little appreciation of these facts. In order to change from the “old” industry to a “new” industry, the concept of “sustainability” should be introduced as a fundamental idea. The fundamental aspects for considering the sustainability of mankind and the Earth are society, economy, and environment. The essence of the construction industry can be appreciated from these views. There exists interconnection among safety, cost, and environmental impact. In the existing “old” construction engineering, this interconnection is not dealt with systematically. This paper outlines the background on the necessity to introduce a “sustainability” philosophy into the construction sector and proposes a basic framework for sustainability design as a “new” design system

Since concrete is the most widely utilized construction material, several solutions are currently being developed and investigated for enhancing the sustainability of cementitious materials. One of these solutions is based on producing Recycled Concrete Aggregates (RCA) from existing concrete members resulting by either industrial processes or demolitions of existing structures as a whole. Moreover, waste resulting from industrial processes other than the building construction (i.e., tire recycling, production of steel, powders resulting from other depuration processes) are also being considered as possible low-impact constituents for producing structural concrete and Fiber-Reinforced Cementitious Composites (FRCC). Furthermore, the use of natural fibers is another option for producing environmentally-friendly and cost-effective materials, depending on the local availability of raw materials. To promote the use of concretes partially composed of recycled constituents, their influence on the mechanical and durability performance of these concretes have to be deeply investigated and correlated. This was the main goal of the EnCoRe Project (www.encore-fp7.unisa.it), a EU-funded initiative, whose activities and main findings are summarized in this paper.

Advances in concrete technology have led to the development of a new class of cementitious composites with improved mechanical and durability properties, named high performance concrete (HPC). Along with improved performance of HPC there is high cement consumption in the production of this type of concrete which leads to certain increases in CO2 emissions. Ecological and environmental benefits support the use of waste glass powder as supplementary cementing material by decreasing the necessity for landfills, by the reduction of non-renewable natural resource consumption, by the reduction of energy demand for cement production (less cement is needed), and by reducing the greenhouse gas emissions. The present research is focused on design of an HPC using different glass waste cullet ground along with sand into powders which have the most promising effect on the properties of concrete and the effectiveness of application of new generation poly-phosphonic superplasticizers blended with PCE based superplasticizer for HPC concrete. Portland cement is substituted at a level of 20% by mass with glass waste powder which gives the improvement of workability and mechanical properties of the concrete what makes glass powder a valuable Portland cement substitute.

The main objective this study was to investigate the effect of waste steel fibers on the mechanical properties of concrete. The steel fibers obtained from waste tires were used, and physical and mechanical properties of these fibers were determined as a first step of the study. Fibers having different aspect ratios were used in concretes at various amounts. A concrete without any fibers was also cast. Compressive, flexural and splitting tensile strengths of the concretes were obtained. Fracture energies were also obtained using a closed-loop testing machine. Results showed that post-cracking strength and toughness of the concretes containing waste steel fibers were significantly increased. Flexural and splitting strength of the concretes were also improved. The experimental results showed that the waste steel fibers recovered from waste tires could be used for the production of steel fiber reinforced concretes. Utilization of waste steel fibers can help to protect environment by reducing the need for steel fiber production. Thus, the reuse of waste fibers in concrete contributes to a more sustainable fiber reinforced concrete production. Since the costs of the waste steel fibers are substantially lower than the commercial steel fibers, more economical steel fiber reinforced concretes can also be obtained.

Concrete is the most versatile construction material. However, the image of concrete looks often one of something non-friendly from an environmental point of view. Further developments, “green chemistry” and new techniques, should continue to be introduced into the cement and concrete industry. This will provide distinct alternatives to OPC dominating inside cement market. Simultaneously new scientific and technological breakthroughs are required. One of such additional strategies is based on advanced concrete technology concepts, which enables the reduction of the quantity of cement used in concrete, by combining fillers and various admixtures. Another strategy is based on a new design of the structural component, to evaluate the use of different materials and to achieve an overall reduction of the environmental impacts. This strategy highlights Life Cycle Analysis and Design, Performance Standards for Durability, Environmentally Driven Design and the role of the reinforcement, because the conventional steel reinforcement contributes to environmental footprint as much as the cement in the concrete. Composite materials, including polymer composite reinforcement, non-metallic fibers and the external reinforcement for repair and strengthening, would be widely used in modern construction. Additional benefits of synergy between these different solutions might be realized leading to reduction of more than 50% of environmental load.