| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for reducing drying shrinkage of lightweight concrete having satisfactory working property with a light weight and excellent in appearance and strength by mixing a lightweight aggregate dried with a percentage of water absorption of a prescribed value or less, cement, a water reducing agent, and water. 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 reduce the drying shrinkage. As the cement, alumina cement, general Portland cement or the like is used, and as the water reducing agent, naphthalene sulfonic acid, polycarboxylic acid or the like is used. As the lightweight aggregate, a natural lightweight aggregate is used, and an artificial lightweight aggregate may by used together. The specific gravity of the lightweight aggregate is set to less than 1, and the ratio of water to cement is preferably set to 50% or less, particularly, 30-50%. Other admixtures may be mixed thereto. The materials are put in a mixture followed by kneading, and portioning water and the water reducing agent are put thereto to perform a main kneading, and the resulting mixture is put in a form. Thus, low drying shrinkage can be provided to eliminate the limitation in design. |
