Temperature-dependent shear bond strength of geosynthetics-reinforced masonry for climate-adapted structural repairs and retrofits in Eastern Canada

Unreinforced masonry (URM) is prevalent in Eastern Canada, yet conventional repair/retrofit research provides limited evidence on the sub-zero bond response of mortar-embedded textiles. Canada’s. This study investigates the temperature-dependent bond behaviour of a novel geosynthetics-based repair/retrofit system for clay brick assemblies representative of Eastern Canada – particularly using ductile polypropylene (PP) and stiff fibreglass (FG) geogrids embedded in type O mortar. This paper is the first to include an experimental programme comprised of single-sided pull-out tests with varying embedment lengths and single-lap shear bond (SLSB) tests between −30˚C and 40˚C using an adapted RILEM 250-CSM configuration. A total of 48 pull-out and 75 SLSB tests divided between PP and FG were performed. Peak pull-out load increased approximately fivefold between 50 and 200 mm, with no plateau observed within this range. At RT, FG mobilized a nominal average bond strength of 0.26 MPa and an equivalent peak axial stress of 547 MPa, compared with 0.14 and 186 MPa for PP, whereas PP sustained greater global displacement values. The temperature conditioning further modified both the bond capacity and governing failure mode. The −10˚C condition produced the most critical response, reducing peak load by 18% for PP and 47% for FG relative to RT, with matrix-to-substrate debonding governing both systems. These findings provide interface-scale evidence of temperature-dependent load transfer in geogrid-mortar assemblies, a basis for bond-slip calibration and component-scale validation under Eastern Canadian service conditions.