Compression tests and design evaluation of double-skin composite walls incorporating eco-friendly basalt fiber–reinforced recycled concrete

Abstract

Recycled aggregate concrete (RAC) is a sustainable material, offering the benefits of reducing carbon dioxide emissions and economizing natural aggregate resources. However, its application in high-rise buildings remains limited. Therefore, this study proposes a novel truss-stiffened double-skin composite wall filled with RAC. Eight specimens were tested under axial compression. The failure modes, load-axial strain curves, and local strain responses were obtained. The effects of the recycled aggregate replacement ratio (30%, 50%, 70%, and 100%) and basalt fiber content (0, 2, 4, and 6 kg/m 3 ) on the load-axial strain response, peak load, strength index, peak strain, composite elastic modulus, and ductility index were analyzed. Results show that the failure was dominated by the local buckling of the faceplates and boundary columns. As the replacement ratio increased from 30% to 100%, the bearing capacity decreased by 7.4%, while the peak strain and ductility index increased by 37.7% and 11.2%, respectively. As the basalt fiber content increased from 0 to 6 kg/m 3 , the peak strain increased by 32.0%. The bearing capacity was slightly enhanced at a basalt fiber content of 2 kg/m 3 , whereas excessive fiber addition led to a reduction in capacity. Moreover, the suitability of four design codes for the novel composite wall was assessed. Among these codes, T/CECS 926‑2021 is recommended for compressive capacity design due to its relatively accurate and conservative predictions. The outcomes of this research could offer valuable insights for the application of RAC in high-rise buildings.