| 摘要 |
<p>PROBLEM TO BE SOLVED: To produce low environmental load type high strength concrete having compressive strength equal to a specified value or higher when the age is a specified value, and a unit carbon emission weight equal to a specified value or lower, by blending blast-furnace slag cement with anhydrous gypsum that is produced as an industrial byproduct and has a specified pH, and forming the resulting blend into concrete. SOLUTION: This concrete is obtained by blending blast-furnace slag cement with anhydrous gypsum that has a <=pH 4.5 and is produced as an industrial byproduct, and forming the resulting blend into concrete having a >=60 N/mm2 compressive strength value when the age is 28 days, and a <=55 kg-C/m3 unit carbon emission weight, wherein, as the gypsum used, anhydrous gypsum is particularly preferred because other gypsum such as dihydrate gypsum or hemihydrate gypsum, has not good capability of effecting strength of the resulting concrete, also this anhydrous gypsum preferably has particle size appropriate to provide a 3,000-10,000 cm2/g Blaine specific surface area and, in the concrete mix, the blending ratio of the anhydrous gypsum is preferably 10-50 kg/m3; and further, the anhydrous gypsum produced as an industrial byproduct is used preferably in combination with a fine siliceous powder such as fumed silica or silica dust, from the viewpoint of the capability of effecting sufficient strength of the resulting concrete.</p> |
