Multiscale Investigation of Premix Glass Fiber–Reinforced Concrete: Experimental Case Studies and Constitutive Back-Analysis

This study presents a multi-scale performance investigation of premix glass fiber-reinforced concrete (GRC) elements, integrating experimental case studies, novel casting techniques, and advanced nonlinear finite element analysis (FEA). The research introduces a bottom-up low-pressure casting method that enhances fiber-distribution, surface quality, and dimensional accuracy overcoming limitations of traditional spray methods in both formwork efficiency and material uniformity. Experimental testing of full-scale facade panels, trench covers, and architectural wall units demonstrated that the inclusion of alkali-resistant glass fibers led to an average of 95% increase in flexural strength, a 60% increase in post-cracking ductility, and a 60% weight reduction compared to conventional reinforced concrete. Qualitatively, the premix GRC elements exhibited smoother finishes, superior compaction, and minimal defect formation. Numerical simulations using nonlinear FEA revealed strong agreement with experimental results, with predicted peak load and displacement responses within ±10% of test data. The constitutive model accurately captured crack initiation, stiffness degradation, and strain localization, with improved representation of post-peak behavior compared to conventional smeared crack models. Comparative analysis showed that the proposed model improved accuracy in peak load prediction by 15 to 20% over standard concrete models. New findings include a validated numerical framework for simulating complex GRC behavior under flexural and combined loading, as well as insights into stress redistribution in fiber-reinforced sections. This integrated experimental and numerical approach supports the design of lightweight, high performance prefabricated GRC components, offering practical benefits for sustainable and efficient construction in facade, utility, and infrastructure applications.