ABSTRACT
The purpose of the work was to propose analytical model considering double confinements (provided by both transverse reinforcements and a wide flange steel section), which was verified by the nonlinear finite element analysis considering concrete-damaged plasticity. The scope of the effort and the procedures to achieve the aim of this study included the identification of the concrete confinements provided by both transverse reinforcements and a wide flange steel section based on the elasto-plastic model in tension for both rebar/steel sections and elasto-buckling for rebars in compression. The influence of rebar buckling in the compression zone on flexural moment strength was also investigated with and without considering confining effects offered by steel sections. The analytical approach predicted a post-yield behavior of composite beams based on the confining effect offered by both the shear reinforcement and wide steel flange sections. However, for beams without axial loads, the compressive zones with high and partial confinements for concrete sections at the yield and maximum load limit state were limited when compressive buckling failure was not considered, preventing the confining factors from significantly influencing the flexural load resisting capacity. An accurate flexural capacity of composite beams can be obtained when rebar was modeled with buckling in the compression zone.
ABSTRACT
To prevent chemical erosion of concrete and improve chemical resistance, reinforced concrete flumes were manufactured, conforming to the Korean Industrial Standards (KS). Two different sizes of liquid crystal display (LCD) waste glass powder (LWGP) particles were used (i.e., 5 and 12 µm) with two substitution types with cement in concrete (i.e., 10% and 20%). Changes in compressive strength, pore structure, weight, volume, and strength of the concrete flumes after immersion in two sulfate solutions (i.e., Na2SO4 and MgSO4) for 84 and 182 days were measured for sulfate attack resistance. The applicability of the LWGP concrete flume with a 0.5 mm crack width was also evaluated based on the bending strength results. The LWGP5, which has a smaller particle size among LWGPs, filled the smaller pores, thereby reducing the porosity and contributing to the compressive strength gain. Higher volume and weight change ratios for all specimens immersed in MgSO4 solution were found than those immersed in Na2SO4 solution under identical conditions. Flexural loads of all the LWGP concrete flumes with 0.05 mm crack widths were greater than 48.5 kN, as required by the KS code; however, these flexural loads were lower than those of ordinary Portland cement. The applicability was also validated via a flexural test complying with KS.
