Evaluation of Ultra-High-Performance Concrete Columns at High Temperatures after 180 Days of Curing

Ultra-high-performance concrete (UHPC) is a material that has high compactness, low porosity, and mechanical strength, with especially tensile strength. Due to these characteristics, the behavior of when exposed temperatures debatable. The amount fibers in mixture, which makes UHPC present seen as one arguments for good performance temperatures. objective this study was evaluate behaviors ultra-high-performance columns hybrid steel polypropylene no loose reinforcements subjected elevated after 180 days curing. exposure age, less than 90 days, results greater damage due spalling, because this, sought higher age. Two were manufactured cross-section 250 mm × height 2800 mm. A heating regime followed curve standard ISO 834-1. physical characteristics samples evaluated during measurements decreases surface aspect. Effects on compressive modulus elasticity, apparent density cylindrical test bodies 100 diameter 200 height. These cured same regime, cooling. showed an increase strength increasing temperature up factor 30% at 400 °C. elasticity decreased gradually increased, maximum 29% 6%, respectively. Throughout heating, audible cracks heard from spalling. spalling frequency peaked oven 600 °C, testing suspended 78 min complete rupture column section. On average, 46.5% cross-sections suffered