Abstract
Concrete production unfavourably affects the environment due to high energy demands of cement production and consumption of limited natural resources. Therefore, waste utilization in fabrication of cementitious material is beneficial and legitimate. Significant reduction of environmental impact can be secured by utilization of various types of wastes or byproducts used for a partial substitution of cement binder or aggregates. However, the use of waste materials usually leads to deterioration of material properties of the designed composites. Therefore, it is very important to thoroughly investigate important materials properties to verify performance and practical usability of the newly designed materials. In this paper, three types of concrete mixes were designed. The reference concrete involved fine and coarse natural riverbed aggregates and two other mixes were designed using both, natural and recycled aggregates represented by crushed concrete paving cobbles. Concretes were tested in terms of basic physical properties (bulk density), mechanical properties (compressive strength), thermal properties (thermal conductivity, specific heat capacity, thermal diffusivity), and hygric properties (water vapour diffusion resistance factor, water vapour sorption at 97% RH, water absorption coefficient, moisture diffusivity) and experimentally determined data were compared and discussed. It was observed that materials properties of concretes with recycled aggregates are comparable with those of the reference concrete which is a promising fact from the environmental point of view.
Highlights
The utilization of recycled materials in the construction industry is systematically gaining on importance
It was observed that materials properties of concretes with recycled aggregates are comparable with those of the reference concrete which is a promising fact from the environmental point of view
With respect to the sustainability of industrial production, it exists a legitimate demand for environmental protection which can be partially ensured by meaningful reuse of the waste resulting in the production of building materials with favourable materials properties and sufficiently high utility value comparable with building materials made of primary resources
Summary
The utilization of recycled materials in the construction industry is systematically gaining on importance. With respect to the sustainability of industrial production, it exists a legitimate demand for environmental protection which can be partially ensured by meaningful reuse of the waste resulting in the production of building materials with favourable materials properties and sufficiently high utility value comparable with building materials made of primary resources. Taking into consideration that global cement production has increased more than 30 times since 1950, estimated global emissions of CO2 were 1.5 ± 0.12 Gt in 2018, cumulative global emissions were of 38.3 ± 2.4 Gt CO2 between 1928 and 2018, 71% of which have occurred since 1990 [3], it exists a legitimate demand on the use of alternative binders with significantly decreased influence on the environment or the use of recycled cementitious materials utilized in new concrete mixes. We focused on the design of three concrete mixtures with various dosages of coarse aggregates including the recycled ones originating from crushed concrete paving cobbles and their material characterization in terms of basic physical, thermal and hygric properties
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