Mechanical Properties and Durability of Concrete Composites Incorporating Recycled Concrete Aggregate and Porcelain Aggregate

Authors: *Unamba, K.U., Medjor, E.A. And Saleh, J.Y.

DOI Info: http://doi.org/10.5281/zenodo.21046989

ABSTRACT

This study examines the mechanical properties and durability performance of concrete composites in which recycled concrete aggregate (RCA) and porcelain aggregate (PA) partially replace natural coarse aggregates. Five concrete mix designs were prepared: a control mix (M0) made entirely with natural coarse aggregate and four modified mixes (M1 to M4) containing varying proportions of RCA and PA. Experimental tests measured compressive strength, splitting tensile strength, flexural strength, water absorption, depth of water penetration, and sulphate resistance after 28 days of water curing. The results showed that RCA reduces mechanical performance and durability because of its elevated porosity and adhered old mortar, whereas PA improves both properties through its dense, angular, vitrified microstructure. Mix M2 (50% PA replacement) achieved the best performance among all modified mixes, with a compressive strength of 30.1 MPa, splitting tensile strength of 2.80 MPa, flexural strength of 4.85 MPa, water absorption of 3.7%, penetration depth of 17 mm, and sulphate mass loss of 2.1%, all close to the control values. Mix M3 (25% RCA and 25% PA) also delivered acceptable structural and durability characteristics, indicating effective synergy between the two recycled aggregate types. These findings confirm that porcelain waste can serve as a viable and sustainable substitute for natural aggregates, while moderate RCA incorporation remains appropriate for non-critical structural applications. The study provides useful performance-based evidence to support sustainable aggregate selection in concrete infrastructure and advances understanding of hybrid recycled aggregate systems.

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