STUDIES ON CONCRETE RECYCLED BUILDING MATERIALS

Civil Engineering

Construction industry uses cement which is known to be a heavy contributor to the CO2 emissions and environmental damage. Incorporation of industrial wastes like demolished old concrete, silica fume (SF) and fly ash (FA) as supplementary cementing materials (SCMs) could result in a substantial reduction of the overall CO2 footprint of the final concrete product. However, use of these supplementary materials in construction industry especially in the making of concrete is highly challenging. Significant research efforts are required to study the engineering properties of concrete incorporating such industrial wastes. Present research is an effort to study the properties of concrete incorporating industrial wastes such as demolished concrete, SF and FA. Recycled coarse aggregate (RCA) concrete construction technique can be called as ‘green concrete’, as it minimizes the environmental hazard of the concrete waste disposal. Indian standard recommends target mean compressive strength of the conventional concrete in terms of water cement ratio (w/c). The behaviour of RCA concrete, prepared from two samples of parent concrete having different age groups, is investigated, to propose the relationship of compressive strength with water cement ratios, in the present study. Number of recycling may influence the mechanical properties of RCA concrete. The influence of age and number of recycling on the properties such as capillary water absorption, drying shrinkage strain, air content, flexural strength and tensile splitting strength of the RCA concrete are examined. While the compressive strength reduces with number of recycling gradually, the capillary water absorption increases abruptly, which leads to the conclusion that further recycling may not be advisable.

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.