Experımental Behavıour of Shear-Crıtıcal Beams Produced From Geopolymer Concrete

Abstract

Portland cement consumption tends to grow continuously with the increasing population and developing infrastructure works. It is known that Portland cement production causes a very high energy consumption and is responsible for approximately 8% of human-induced carbon dioxide emissions. At the same time, natural resources are consumed quickly with the production of Portland cement. Considering the damages of Portland cement to nature and the environment, it is of great importance to developing alternative environmentally friendly and sustainable building materials. On the topic of global warming, which has attracted the attention of the whole world in recent years, eco-friendly building materials will be very beneficial to nature.

On the other hand, due to the increasing population, the continuous infrastructure and urbanization cause a large amount of construction and demolition waste. In addition to maintenance and repair works, the significantly increasing urban transformation works leave behind a considerable amount of solid waste. In addition to the environmental damage of these solid wastes, storage in large clean areas is another issue that should be considered. In this context, recycling these construction and demolition wastes in the most beneficial way possible has attracted the attention of the construction industry in recent years. The transformation of construction and demolition wastes into building materials with appropriate recycling techniques will bring significant economic, social, and environmental benefits.

Considering the harmful effects of Portland cement, interest in the production of aluminosilicate-based materials with alkali activation has increased in recent years. In this context, the most essential material class that stands out is called geopolymer. Geopolymers are produced by the reaction of waste materials with a certain aluminosilicate content with chemical activators such as alkali hydroxide and alkali silicate and have structural and environmental advantages compared to Portland cement concretes. In the literature, there are many studies on the development of geopolymer with materials such as fly ash, silica fume, and blast furnace slag, which are generated as waste materials in the production process of various factories and facilities. As a result of the gradual increase of such waste materials, geopolymer studies are of great importance in order to prevent damage to nature and the environment and to minimize Portland cement production by using it in the development of alternative building materials.

This study aims to develop geopolymer materials as an alternative to Portland cement concrete with the use of construction and demolition wastes, which have been increasing in recent years. Within the scope of the research, the aim is first to develop geopolymer binders with construction and demolition wastes, then to produce geopolymer concrete at a level comparable to Portland cement concretes. In the continuation of the study, it is aimed to compare the results of load-displacement, moment-curvature as a result of four-point bending tests by producing geopolymer beam and reinforced Portland cement beam. The results show that geopolymer beams perform similarly to Portland cement beams. As a result of this study, important outputs have been achieved in developing environmentally friendly and sustainable geopolymer building elements to reduce the harmful effects of Portland cement.