The aim of this study was to present the use of detachable laminated high-yield metal plates for precast concrete column splices. The structural behavior of precast concrete column connections with detachable high-yield-strength (650-MPa) plates with 1,000-MPa high-strength bolts was performed experimentally and numerically. A nonlinear numerical model based on concrete damaged plasticity was developed to evaluate the structural performance of the novel joint for precast concrete columns with fully restrained and partially restrained moment connections. The behavior of the proposed joint obtained numerically was in good agreement with the full-scale test data, offering accurate prediction of stresses and strains for the design of the mechanical column connections. Finally, the real-world behavior including strain evolution of the mechanical joints was understood by the strains of microscopic level obtained via the proposed numerical model. This study is expected to contribute to promoting the use of plates with high-yield strength, which possess the merits of bolted column-to-column splices, to implement mechanical joints in precast concrete assembly similar to how steel frames are assembled.

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.