Abstract: Process for stabilizing cement stone, formed with binders rich in aluminates by setting with water, against high elevated temperatures and high humidity which comprises adding calcium sulfite to the aluminous binder material prior to setting. In another embodiment of the invention the addition of calcium borate along with the calcium sulfite provided even greater stability both initially and over a period of time. Calcium sulfite formed as a by-product of the waste gas purification of furnaces is the main source of supply for purposes of this invention.

Abstract: In a building material comprising an inorganic binder selected from the group consisting of Portland cement, alumina cement, calcium silicate, lime and gypsum, structurally reinforced with glass fibers, the improvement which comprises employing as said glass fibers alkali-resistant calcium silicate glass fibers consisting essentially of approximately______________________________________ CaO 26 - 50 % by weight SiO.sub.2 40 - 65 Al.sub.2 O.sub.3 1 - 8 ZnO+ZrO.sub.2 +Cr.sub.2 O.sub.3 0.1 - 10 Fe.sub.2 O.sub.3 and Na.sub.2 O < 2.

Abstract: In a building material comprising an inorganic binder selected from the group consisting of Portland cement, alumina cement, calcium silicate, lime and gypsum, structurally reinforced with glass fibers, the improvement which comprises employing as said glass fibers alkali-resistant calcium silicate glass fibers spun and drawn from molten phosphorus slag, said fibers consisting essentially of approximately______________________________________ CaO 10-60% by weight SiO.sub.2 35-70 Al.sub.2 O.sub.3 1-10 ZnO+ZrO.sub.2 +Cr.sub.2 O.sub.3 +TiO.sub.2 0.1-10 Fe.sub.2 O.sub.3 and Na.sub.2 O <2.