Patent ID: 8679389

Claim:
A method for producing composite structural material comprising in combination: providing a cementitious matrix; positioning a plurality of steel reinforcing rods positioned in the cementious matrix; and substantially encapsulating each respective steel reinforcing rod in a vitreous shell; and substantially encasing the plurality of steel reinforcing rods in the cementitious matrix; wherein each respective steel reinforcing rod has a coefficient of thermal expansion of between about 14 ppm/° C. and about 17 ppm/° C.; and wherein each respective vitreous shell has a composition consisting essentially, in weight percent, of about 33-45% SiO 2 , 3.5-4.6% Al 2 O 3 , 13.5-19.5% B 2 O 3 , 4-13.5% K 2 O, and 5.5-15.5% ZrO 2 ; and wherein each respective vitreous shell has a coefficient of thermal expansion between about 12.5 ppm/° C. and about 13.5 ppm/° C.