Investigation of Flexural Capacity of Normal and Recycled Aggregate Concrete Filled Steel Tubes

This paper aims to compare the experimental and theoretical results of the flexural capacity of normal and recycled aggregate concrete-filled tubes (CFT).

Background: The experimental results of 47 CFT specimens made of natural aggregate (NA), recycled concrete aggregate (RCA), and recycled asphalt pavement (RAP) with steel thicknesses of 2 and 2.4 mm from previous research performed by the authors are adopted.

The NA was replaced in the CFT specimens by RCA and RAP with replacement levels of 20%, 40%, 60%, 80%, and 100%. The theoretical study is conducted in this paper based on the provisions of many international codes, available models from the literature, and finite element analysis (FEA) using Abaqus software to obtain the best approach for determining the flexural capacity of CFT.

The results showed that all code provisions were safe to use as they provided conservative results except for the ACI 318-19. The ANSI/AISC 360-16 and CoPHK provided the best conservative and accurate results.

Besides, the finite element analysis results were found in good agreement with the experimental results as they provided the most accurate estimation.