Analysis of some parameters (variation of boundary conditions and reduction of mechanical properties of materials) of high-performance concrete columns, depending on temperature changes

Abstract

This research examines the fire performance of high-performance concrete (HPC) columns by analyzing the impact of boundary condition variations and the degradation of mechanical properties under elevated temperatures. The study investigates four HPC mixtures: a reference mix (HPC), polypropylene fiber-reinforced HPC (HPCPP), date palm fiber-reinforced HPC (HPCDP), and a hybrid mix combining both fibers (HPCPPQS). The primary objective is to enhance the thermal resistance and structural integrity of HPC through fiber reinforcement. Experimental results demonstrate that the HPCDP mix exhibits superior fire resistance, retaining 57% of its load-bearing capacity at 650°C while effectively reducing spalling and crack formation. The incorporation of date palm fibers significantly improves the thermal stability of HPC by enhancing moisture dispersion and mitigating internal stresses. Additionally, numerical simulations using SAFIR software were conducted to model RC column behavior under fire exposure, emphasizing the influence of cooling phases and material composition on structural stability. The findings highlight the effectiveness of fiber-reinforced HPC as a sustainable and cost-efficient solution for improving fire resistance in structural applications. This study advocates for performance-based fire safety design to enhance the resilience of HPC columns subjected to high-temperature conditions.