| 摘要 |
PROBLEM TO BE SOLVED: To provide a lightweight concrete having a low percentage of water absorption and excellent in durability by mixing a lightweight aggregate having a percentage of water absorption of a prescribed value or less, cement, a water reducing agent, and water together to prepare freshly mixed concrete, and placing it in a form followed by hardening. SOLUTION: A lightweight aggregate dried in absolute dry condition or with a percentage of water absorption of 50% or less, cement, a water reducing agent and water are mixed together to prepare freshly mixed concrete, and it is placed in a form to provide a lightweight concrete formed body. As the cement, alumina cement, general Portland cement or the like is used, and as the water reducing agent, polycarboxylic acid or the like is used. As the lightweight aggregate, a natural lightweight aggregate or an artificial lightweight aggregate is used. The specific gravity of the lightweight aggregate is set to less than 1, and the ratio of water to cement is preferably set to 60% or less, or within the range of 32% to 60%. Each material is put in a mixer followed by kneading, and proportioning water and the water reducing agent are put thereto perform a main kneading. Thus, a low percentage of water absorption can be provided, and a lightweight concrete having satisfactory working property with a light weight, and excellent in appearance with a high strength can be provided. |
