Abstract: A body (5) of set, initially pasty material, such as concrete, includes an electrically conducting path formed by a concentrated layer (6) of electrically conducting magnetizable elements, such as fibers (F) or granules (G), embedded in the initially pasty material and extending through at least a portion of the body (5). Electrically conducting terminal members (9) may be connected to the electrically conducting layer (6) at spaced-apart positions along the layer (6). A method of providing such a body (5) includes the steps of: (a) forming a body of the pasty material in which electrically conducting magnetizable elements (F) are dispersed, (b) applying a magnetic field to the body of pasty material to form from the magnetizable elements an electrically conducting layer embedded in the body of pasty material and extending at least through a portion the body (5), and (c) causing the body of pasty material containing the layer (6) to set.