Issue 78

S. A. Mustafa et alii, Fracture and Structural Integrity, 78 (2026) 298-314; DOI: 10.3221/IGF-ESIS.78.18

testing was 25 MPa. The reinforcement bars had average yield strengths of 360 MPa for the 12, 16, and 18 mm bars, while the 8 mm transverse reinforcement had a yield strength of 260 MPa. Specimen types and design The experimental program consisted of two groups of specimens. The first group consisted of twenty-three Pull-out test cylinders used to assess bond strength and identify the optimal installation parameters for implanted reinforcement; as shown in Fig. 1. The second group consisted of four large-scale shear wall specimens used to study the cyclic lateral behavior of walls anchored with different embedment lengths. Pull-out test specimens (stage I) The twenty-three pull-out specimens were cylindrical concrete samples, each 150 mm in diameter and 300 mm in height. After curing, the cylinders were drilled to create holes with diameters equal to 1.125 ϕ , 1.25 ϕ , and 1.375 ϕ , where ϕ is the bar diameter. Into these holes, 16 mm and 18 mm high-strength deformed bars were implanted and bonded using two types of commercially available adhesive in the market. These anchoring materials were used to bond the implanted steel bars into the drilled holes. Fig. 2 shows the implanting process of the reinforcement bars.

Figure 1: Pull-out and shear wall specimens.

Figure 2: Implanting process of the reinforcement bars in cylindrical specimens.

Two different bonding materials were used during the pull-out tests: CMB (Chemicals for modern building) and Sika (Sika Egypt for Construction chemicals). The main technical properties of the adhesive materials used in the experimental program are summarized in Tab. 1, based on the manufacturers' technical datasheets. CMB is a high-strength, two component chemical anchor system designed for anchoring steel into hardened concrete. Its viscosity, curing properties and ability to fill micro gaps, made it particularly suitable for the implanting process used in this study. The other bonding material Sika, comes as a two-part system packaged in dual cartridges, which makes it easy to mix the components automatically during the application. After being mixed, the resin is injected into the hole that was drilled, where it flows around the reinforcement bar and fills in any gaps. It makes a strong, reliable bond with both the steel and the concrete around it as it hardens. The pull-out results showed that CMB was a better adhesive, due to its higher load capacity and

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