Properties of calcium sulfoaluminate cement made ultra-high performance concrete: Tensile performance, acoustic emission monitoring of damage evolution and microstructure Jun-Yan Wang a,b , Zhen-Zhen Chen b , Kai Wu a,b,⇑ a Key Laboratory of Advanced Civil Engineering Materials (Tongji University), Ministry of Education, 4800 Cao’an Road, Shanghai 201804, China b School of Materials Science and Engineering, Tongji University, 4800 Cao’an Road, Shanghai 201804, China highlights ES-UHPC exhibits significant tensile strain-hardening behavior at early age. ES-UHPC obtain high ductility and bonding between steel fiber and matrix at 1 d. Damage evolution was monitored by acoustic emission method. AE analysis proves that the ES-UHPC exhibits multiple cracking behavior at 28 d. Ettringite is the main hydrates and the content increases rapidly from 4 h to 1 d. article info Article history: Received 4 May 2018 Received in revised form 11 December 2018 Accepted 7 March 2019 Keywords: Calcium sulfoaluminate cement Ultra-high performance concrete Tensile performance Damage evolution Acoustic emission Microstructure abstract The properties of early age strength ultra-high performance concrete (ES-UHPC) made with calcium sul- foaluminate (CSA) cement, including tensile performance, damage evolution monitored by acoustic emis- sion (AE) and microstructure were evaluated in this work. Results show that the ultimate tensile strain e Utu of ES-UHPC can reach to 0.199% at 1 d, which is 4.23 times larger than that of normal UHPC (N- UHPC) at the same testing age. AE testing results indicate that both types of UHPCs exhibit multiple cracking behavior at 28 d. With the tensile strain developing, the two UHPCs show a similar damage evo- lution trend and multiple microcracks with crack-width smaller than 0.01 mm generated after 0.046% strain reached. Microstructure tests demonstrate that ettringite presented after 4 h and the content increased significantly from 4 h to 3 d, which contributed to the early mechanical properties for ES- UHPCs. Ó 2019 Elsevier Ltd. All rights reserved. 1. Introduction Concrete is one of the most commonly used construction mate- rials in the world [1,2]. With aging of these constructions, many concrete structures are in urgent need of effective and durable repair [2–4]. For example, almost 27% of all highway bridges are in need of repair or replacement in the USA [5]. Various of advanced materials and techniques have been devel- oped and applied in restoration projects. Unfortunately, it has been estimated that up to half of all concrete repairs fail and about 3/4 of the failures are attributed to the lack of durability [6,7]. In previous studies, most researchers focused on increasing the strength of repair materials or the bond strength between a repair material and the concrete substrate [8]. However, with the strength increas- ing, brittleness is even more pronounced, as it is more prone to cracking. To reach durable repairs of civil infrastructure, concrete repair materials should have high tensile ductility to suppress brit- tle fracture [7,9–11]. Ultra-high performance concrete (UHPC) is a type of cementi- tious composites characterized by remarkable mechanical and durability properties, and it has gained extensive attention over the past decades [12–15]. According to the Swiss standard SIA 2052–2016 [16], UHPCs can be divided into three types based on the tensile behaviors,: UO (strain softening), UA (ultimate tensile hardening strain is higher than 1500le) and UB (ultimate tensile hardening strain is higher than 2000le). Strain-hardening UHPC (UA and UB) can be classified as strain-hardening cementitious https://doi.org/10.1016/j.conbuildmat.2019.03.057 0950-0618/Ó 2019 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Key Laboratory of Advanced Civil Engineering Materials (Tongji University), Ministry of Education, 4800 Cao’an Road, Shanghai 201804, China. E-mail addresses: [email protected], [email protected] (K. Wu). Construction and Building Materials 208 (2019) 767–779 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat
Properties of calcium sulfoaluminate cement made ultra-high performance concrete: Tensile performance, acoustic emission monitoring of damage evolution and microstructure
May 05, 2023
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Related Documents
