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原文传递 Mitigating early-age oraoking in thin UHPFRC precast concrete products using shrinkage-reducing admixtures

题名：	Mitigating early-age oraoking in thin UHPFRC precast concrete products using shrinkage-reducing admixtures
正文语种：	英文
作者：	Doo-Yeol Yoo;Nemkumar Banthia;Young-Soo Yoon
作者单位：	University of British Columbia in Vancouver;Architectural Engineering at Korea University
关键词：	Cover depth;degree of restraint;shrinkage-reducing;admixture;slab;surface cracking;ultra-high-performance fiber-reinforced concrete
摘要：	This study investigates the effects of shrinkage-reducing admixture (SRA) and cover depth on the shrinkage and surface-cracking behaviors of ultra-high-performance fiber-reinforced concrete (UHPFRC) slabs. Three different SRA-to-cement weight ratios of 0%, 1%, and 2%, and three different cover depths, 5, 10, and 20 mm (0.2, 0.4, and 0.8 in.), were considered using nine UHPFRC slabs with steel reinforcing bars. Three more unreinforced UHPFRC slabs with three different SRA ratios and four different depths were also fabricated for the comparisons. The use of SRA exhibited better behavior with regard to the decrease of shrinkage, maximum evaporation rate, and maximum surface-crack width. In addition, the application of a larger cover depth was favorable because it caused a lower degree of restraint, leading to a lower cracking potential and a higher surface-cracking resistance. Finally, the minimum required cover depth of the UHPFRC slab is suggested to be 1.3 times larger than the diameter of the upper steel reinforcing bar in order to prevent surface cracking.
出版日期：	2016.01-02
出版年：	2016
期刊名称：	PCI-Prestressed Concrete Institute Journal
卷：	Vol.61
期：	No.01
页码：	39-50