Factors influencing the properties of sclc and structural steel tube columns infilled with sclc

The main utilization of structural lightweight concrete is to decrease the dead load of the structure, which then permits the structural designer to diminish the size of columns, footings, and other load bearing members. The aim of the present thesis is twofold, firstly, it attempts to identify and describe experimentally the behavior of self-compacting lightweight concrete (SCLC). Secondly, it investigates numerically the ultimate strength of concrete filled steel tube (CFST) stub columns with SCLC concentrically loaded in compression to failure. To this aim, 18 SCLC mixtures were designed by considering different water to binder ratios (w/b) of 0.25 to 0.5, nano-silica (nS) contents of 0 to 5.0%, and untreated/treated artificial lightweight aggregates. They were tested for the fresh, mechanical, and durability performance at different ages. Thereafter, to assess the compression resistance of the circular composite columns, various diameter to wall thickness ratios (D/t) of 25 to 100, steel tube yield strength (fy) of 200 to 650 MPa and compressive strength of SCLC of 30 to 85 MPa were used in the investigation. Comparison were made with predicted column strengths using the existing design codes such as ACI, Eurocode 4, and DL/T. For each code, a total of 576 strength results for the circular CFST columns with SCLC were obtained and discussed accordingly. It was observed that the designed SCLC mixtures had comparable and satisfactory engineering performance. In addition, the results in this study showed that the codes estimated a reasonable capacity for the composite columns incorporating SCLC.