Effect of Doped Glass Fibers on Tensile and Shear Strengths and Microstructure of the Modified Shotcrete Material: An Experimental Study and a Simplified 2D Model

Abstract

Shotcrete material has found extensive applications as a reinforcing material in the engineering sector. This study examined the effect of doped glass fibers on the mechanical performance of the modified shotcrete material composed of aeolian sand, fly ash, cement, quicklime, and doped glass fibers. Its tensile and shear strengths values were experimentally determined via a WAW-1000D computerized hydraulic universal tensile testing machine. Its microstructure was analyzed via a size analyzer, scanning electron microscope (SEM), and X-ray diffractometer (XRD). A 2D simplified mechanical model was elaborated to reflect the influence mechanism of the doped glass fibers on the mechanical performance of the modified shotcrete material. The experimental and mechanical analysis results indicated that, at the macroscopic scale, the experimental tensile and shear strengths of the shotcrete material doped with glass fibers were significantly higher than those of the undoped shotcrete material (by up to 310% and 596%, respectively). These results were in concert with the proposed model predictions, where the compound stresses in the shotcrete material were derived as the sum of the stress borne by the shotcrete material itself and the bridging stress exerted by the glass fibers. At the microscopic scale, SEM observations also revealed that the glass fibers were intertwined with each other and tightly enveloped by the shotcrete material particles within the modified shotcrete specimens, connecting the particles of different components into a whole and improving the overall mechanical strength. In addition, the relationships of the compound stress of the shotcrete material vs. embedment length, embedment angle, and cross-sectional area of the glass fibers were established. The research findings are considered instrumental in clarifying the mechanism by which the glass fibers influence the mechanical performance of shotcrete materials and optimize their solid waste (fly ash and quicklime) utilization.

The Influence of Multi-Size Basalt Fiber on Cemented Paste Backfill Mechanical Properties and Meso-Structure Characteristics

“…When tracing and reconstructing BF in the microscopic model, the cylinder correlation method needs to be used to set the fiber segmentation tracking correlation coefficient. Based on the search cone algorithm (Figure 6), set the length, angle, and minimum step size parameters to be segmented and tracked [47,48]. The search cone will determine the voxel P with the highest correlation coefficient as the starting point for fiber tracking, and the voxel placement angle is γ. P c is another related voxel within the search cone, connecting P and P c voxels to form fiber segments, and P c is a fiber composed of multiple fiber segments that are the same as PP c .…”

Review of the Influence of Acrylate Lotion on the Properties of Cement-Based Materials

“…When the volume fractions of glass fibers were 4.5, 4.0, 3.5, and 3.0%, compared with ordinary concrete, the compressive strength, flexural strength, splitting tensile strength, and bonding strength were significantly improved, as shown in Table 1. According to Cunli Zhu et al [79], the tensile and shear test strengths of concrete materials with added glass fibers increased by 310% and 596%, respectively, compared to those without glass fibers. At the micro level, glass fibers were intertwined in the samples of glass fiber-modified concrete, tightly wrapping the concrete into a whole and improving the overall mechanical properties [80].…”