# Steel-Reinforced Polyurethane with Mineral Interlayer for Masonry Protection: Laboratory Tests

## TL;DR

This study tests a steel-reinforced polyurethane system with a mineral layer for protecting masonry, finding that the system performs well but the interlayer thickness affects its strength.

## Contribution

The novelty lies in evaluating a steel-reinforced polyurethane system with a mineral interlayer for masonry protection through experimental testing.

## Key findings

- Reference specimens without a mineral interlayer carried higher loads than those with an interlayer.
- Increasing the interlayer thickness reduced the shear bond strength.
- The SRPU system outperformed previous results in monotonic testing.

## Abstract

This paper presents the results of an experimental investigation on a steel-reinforced polyurethane (SRPU) composite system with a mineral interlayer, designed for the protection of existing structures. The composite SRPU was reinforced with unidirectional steel textile embedded in polyurethane matrix PS. In the study, SRPU was applied to a brick substrate via a layer of lime- or cement-based mortar of a thickness of 3 mm, 6 mm, or 10 mm. Single-lap shear tests (SLSTs) were carried out on specimens with and without a mortar interlayer. The reference specimens without a mineral interlayer carried higher loads than the specimens with an interlayer. An increase in the interlayer thickness reduced the shear bond strength. The stiffness of the bond under shear of the tested systems was unaffected by the presence of the mineral interlayer. The mechanical properties of the applied mortars influenced the observed failure modes. The tested SRPU system demonstrated notable efficiency in monotonic testing, outperforming previously reported results.