On the value of scale factors for determining the strength of concrete in the contact layer of thereinfotcecement anchorage zone

Introduction. Regulatory documents establish two main characteristics of concrete strength: axial compressive strength and axial tensile strength, determined using standard-sized specimens. Concrete strength may be determined using specimens with geometric dimensions that differ, either up or down, from those of standard specimens. In these cases, the concrete strength is adjusted using appropriate scaling factors to bring it into line with the strength of standard-sized specimens.

The scaling factors for converting to the concrete strength of standard samples are also established by the relevant standards. In some cases, experimental determination of concrete strength is a complex task that remains unresolved to this day.

This primarily concerns the strength of concrete in the contact layer of the ribbed reinforcement anchorage zone. Moreover, shear strength parameters for concrete, even for standard specimens, are absent from regulatory documents.

Aim. To determine the scaling factors for calculating the shear and compressive strength of concrete in the contact layer, depending on the strength parameters of concrete in standard specimens.

Materials and methods. Based on an analysis of regulatory documents and open sources, scale factor values were theoretically obtained for determining the actual shear and compressive strength of concrete in the contact layer, taking into account the provisions of the OTS, depending on the concrete strength of standard samples.

Results. Statistical processing of the results allowed us to obtain mathematical relationships between the magnitude of the scaling factors for shear and compression and the height of the transverse ribs of the periodic reinforcement profile.

Conclusions. The scale factor values allow us to determine the ultimate strength of concrete in the contact layer of the reinforcement anchorage zone.

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