PURPOSE: To obtain excellent durability by secondarily curing a primarily cured extruded building material in a specified temp. range.
CONSTITUTION: 100 pts.wt of a hydraulic substance such as portland cement is mixed with 20-60 pts.wt. of a siliceous fine powder such as quartzite fine powder, 20-50 pts.wt. of thin aggregate, 10-30 pts.wt. of such a fibrous material as glass fiber and 1-3 pts.wt. of a thicknener such as methylcellulose, and a specified amt. of kneading water is then added to the mixture and kneaded by a mixer to prepare a kneaded material. The kneaded material is formed into a specified shape by a vacuum extruder, etc., and formed body is cured at high temp. and pressure as the primary curing or wet-cured for a specified period. As a secondary curing, the formed body is heated and then cooled respectively for 2 hr and hydrothermally cured at 50-100°C for 24-48hr, or the formed body is heated and then cooled respectively for 3hr, cured at 100-300°C for 24-48hr to obtain a highly durable formed building material.
EGAMI SEIICHI
TAKAHASHI KATSUHISA
YAMADA YUTAKA
