A Study on restrained thermal cracking controlling technology for high volume blast furnace slag cement concrete

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H04084
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Building structures/Materials
• Research Institution: Kajima Technical Research Institute, Kajima Corporation
• Principal Investigator: Kanda Tetsushi 鹿島建設株式会社(技術研究所), 所幹部, 主席研究員 (40416780)
• Co-Investigator(Kenkyū-buntansha): 溝渕 利明 法政大学, デザイン工学部, 教授 (60339504) ; 濱 幸雄 室蘭工業大学, 工学研究科, 教授 (70238054) ; 小島 正朗 株式会社竹中工務店 技術研究所, 建設材料部, 主任研究員 (80507244) ; 佐川 孝広 前橋工科大学, 工学部, 准教授 (90621045)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 高炉スラグ / マスコンクリート / 温度ひび割れ / 熱膨張係数 / 自己収縮

Outline of Final Research Achievements

This study focused to clarify resisting mechanism and to propose performance improving scheme of high-volume blast furnace slag cement concrete (BC concrete, hereafter) against thermal cracking. A key parameter focused is thermal expansion coefficient (TEC) which is supposed to govern development of restrained thermal stress. Higher TEC causes more restrained thermal stress, and significantly lowering TEC was found to be achieved by increasing amount of trace additives like gypsum and calcium carbonate. Furthermore, chemical analysis of hydration products in BC concrete led to finding optimum composition in binder of BC concrete to restrict transformation of Monosulfate from Ettringite, a source of extending autogenous shrinkage and resulted increasing TEC value. Finally modeling time-dependent change of TEC as formula enables us to precisely predict restrained thermal stress in mass elements involving BC concrete for the first time.

Free Research Field

建築構造材料