Optimized Synergy of Fiberglass Mesh and PP Fibers-Modified Structural Adhesive for Enhanced Mechanical and Microstructural Performance in 3D Printing Concrete (2025-12)¶

The study evaluates the effect of fiberglass mesh, structural adhesive on the mechanical behavior and microstructure of 3D printing concrete (3DPC). The research investigated the interplay between fiberglass mesh strip thickness and structural adhesive application thickness in phase I. Phase II further determined ideal pairings of fiberglass grid density and polypropylene (PP) fiber dosage based on Phase I. The experiment incorporated mechanical evaluations (compressive, flexural, and oblique shear strength testing) and microscopic performance characterization through scanning electron microscopy (SEM) imaging and digital image correlation (DIC) analyses. The 0.3 mm fiberglass mesh and 3 mm structural adhesive configuration (M0.3-A3) is determined as the optimal reinforcing solution to achieve peak compressive (52.15 MPa), flexural (11.04 MPa), and shear strengths (17.36 MPa) in Phase I. Additionally, based on the optimized solution in Phase I, the IN4-P3 composite (4 mm grid interval, 3 vol% PP fibers) demonstrated better microstructure and mechanical strength with 59.86 MPa compressive strength, 14.18 MPa flexural strength and 25.9 MPa shearing strength. Specifically, PP fibers concentrations exceeding 6 vol% impede strength enhancement due to excessive agglomeration while tightest mesh grid interval attained enhanced mechanical performance via a bridging effect. Consequently, tighter 4 mm grid interval combined with moderate 3–6 vol% PP fiber dosage effectively enhances mechanical and microstructural performance. Fiberglass mesh and PP fibers-modified structural adhesive exhibit a synergistic effect that improves mechanical properties, enhancing the construction applicability of 3DPC.