ARDEX BR 345 MICROTEC® Fibre-Reinforced, High Resistivity, Polymer-Modified, Structural Concrete Patching and Repair Mortar is designed for reinstating concrete surfaces damaged through concrete spalling and other chemical or mechanical causes. ARDEX BR 345 is a high-build patching mortar and is capable of being applied up to a thickness of 80mm on vertical, horizontal and overhead surfaces. It is designed to be used for applications where high resistivity of the mortar is required.