Combined Porcelain Ceramic and Recycled Concrete Aggregates Used as Replacement for Coarse Aggregates in Concrete

The increasing production of construction waste on the one hand and the use of concrete as a widely used material in the construction industry, on the other hand, has always led researchers to reuse construction waste in concrete. Among the recycled materials that can be used in concrete, we can mention porcelain ceramic and recycled concrete. In the present study, these two types of recycled aggregates (recycled porcelain ceramics and recycled concrete) alone and together in different percentages of 20%, 40%, and 60% are used as the replacement of coarse aggregates in concrete with a strength of more than 50 MPa and high flowability. Slump test, compressive and flexural strength, water absorption, and water penetration tests have been performed on 150 samples made in 10 mixing designs along with an SEM test. The results showed that all the mixing designs had slumps of more than 180 mm. The compressive strength of the control sample averaged 60 MPa and the samples containing recycled aggregates averaged 68 MPa. Also, by combining two types of recycled aggregates, both the 7-day and 28-day strength increased with increasing replacement percentage with a linear trend. The highest increase was 28% for porcelain aggregates and 17% for combined recycled aggregates. In addition, the water penetration rate in the samples containing the combined recycled aggregates showed a significant decrease compared to the control sample. In the SEM test, it was observed that the samples containing the combined aggregates had a thicker and denser matrix.