Eco-concrete for obtaining “green” construction elements

Abstract

The building materials branch of the construction industry is continuously developing due to occurrence of new products which seek to improve the “green” character of buildings by using different types of wastes. Prefabricated products of different sizes such as blocks, panels, beams and other spatial elements can now be obtained with eco-materials. Concrete is the most used material in the building industry and thus it is necessary to diminish its environmental pollution. There are different ways for improving the “green” character of concrete, such as the addition of waste products of different types (fly ash, silica fume, slag, shredded tyre rubber, agricultural powder wastes, etc.) or by replacing some of the components (i.e. cement, aggregates) with eco-materials. Materials with pozzolanic properties (fly ash, silica fume, banana leaves powder, volcanic tuff, etc.) can, in certain proportions, replace the cement. In order to replace the aggregates, the substitution materials are obtained with sizes which are corresponding to the aggregate sort (polystyrene granules, shredded plastic recipients, agricultural wastes, etc). In the current article, the experimental results obtained on types of eco-concrete used for producing reinforced concrete beams are presented. The eco-concrete used for pouring the reinforced concrete beams contains the following materials: fly ash as replacement for the cement, metalic fibers, polyester fibers and hemp fibers. The beams models were tested in two point bending. The strength capacity and type of failure were analysed and compared as a function of the type of eco-concrete.