Mechanical and fracture properties of concrete with recycled concrete aggregates treated with acids and addition of aluminium sulphate

Forero, J. A.; de Brito, J.; Evangelista, Luís; Pereira, C. H. F.

http://hdl.handle.net/10400.21/22098

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Abstract(s)

The use of recycled aggregates, particularly concrete waste aggregate, has gained increasing popularity and has become current practice in day-to-day applications in many countries. Enhancing the physical and morphological characteristics of this type of aggregate is crucial to promote its widespread adoption. This study investigates the mechanical and fracture properties of concrete incorporating 100 % recycled concrete coarse aggregate (RCA), both untreated and treated with acid solutions of hydrochloric acid (HCl) and sulphuric acid (H2SO4), and addition to the addition of aluminium sulphate (AS). X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques were employed to characterize the cement and aluminium sulphate (AS). The performance of all mixes was evaluated in terms of mechanical properties, including compressive strength, tensile strength, and secant modulus of elasticity. Experimental fracture tests were conducted using the wedge splitting method on notched specimens aged for 28 days. The results demonstrate an improvement in the mechanical behaviour and fracture resistance of mixes incorporating RCA treated with acid solutions at concentrations of 0.3 M, 1 M, and 3 M for HCl, as well as at a concentration of 0.3 M for H2SO4. However, a decrease in properties was observed at higher concentrations of H2SO4 (1 M and 3 M). Furthermore, the addition of AS also resulted in improvements compared to mixes containing RCA.

Keywords

Mechanical properties Fracture energy Wedge splitting test Recycled concrete aggregate Presoaking treatment

URI

http://hdl.handle.net/10400.21/22098

Citation

Forero, J. A., de Brito, J., Evangelista, L., & Pereira, C. H. F. (2024). Mechanical and fracture properties of concrete with recycled concrete aggregates treated with acids and addition of aluminium sulphate. Construction and Building Materials, 447, 1-13. https://doi.org/10.1016/j.conbuildmat.2024.137947