Abstract: The mixture for manufacture of shaped elements of fiber-cement, in addition to minimum 5% by weight of pozzuolanic silicic acid contains also an amount of limestone powder. With this mixture it is possible to obtain a product of high strength properties without tendency to embrittlement respectively to formation of cracks on the surface.In utilizing the mixture for manufacture of shaped elements the latter are moulded from a mixture of aqueous material and permitted to set at 70.degree. to 90.degree. C. during 5 to 12 hours preferably with simultaneous compression.

Abstract: The invention relates to a roofing element, in particular a concrete roofing panel, at whose underside extend a suspension ledge and a base rib, while at least two cross ribs of lesser thickness than the base rib extend in the covering or overlapping region next to the base rib and parallel thereto, with the basic surface of the base rib extending parallel in relation to the outer surface of the roofing element. For increasing the tightness of the roofing element, the thickness of the roofing element of optionally S-shaped or wave-shaped cross section in the apex of the cross rib farthest removed from the base rib is slightly, up to 6 percent at the most, less than the thickness of the roofing element in the base rib and the height of further cross ribs disposed between the base rib and the cross rib farthest removed from the base rib is less than the height of the cross rib farthest removed from the base rib.