Developing Concrete Recycling Strategies by Utilization of Nano-SiO2 Particles

Nowadays, applying sustainable development strategies in designation and production of various products has attracted specific attention. In order to consider ecological sustainable development for a product, reducing its environmental impacts should be observed. Concrete technology and its products are not exceptions, and therefore, the same has been a concern for concrete industry. Alongside, concrete recycling is one of the measures used to reduce the environmental impacts of concrete products during their life cycle. On the other side, positive performance of silica nano-particles has been proven in numerous researches as one super pozzolanic material. Hence, in this study, we aimed on application of recycled coarse aggregates as 100% replacement for natural coarse aggregate. Meanwhile, due to strength loss of recycled concretes, we tried to enhance the microstructural and mechanical properties of recycled concretes by the use of silica nano-particles in low contents (lower than 5%). To provide a more comprehensive investigation, mixtures with different cement contents (350, 400, 450 kg/m(3)) were casted. By examining the experimental data deduced from different tests consisting of slump, compressive strength, water absorption, and microstructure (SEM), the positive effects of this method was discovered. Finally, some procedures for improving the present condition are expressed.