Monitoring of concrete shrinkage and creep using Fiber Bragg Grating sensors Z. Yazdizadeh a , H. Marzouk b , Mohammad Ali Hadianfard c,⇑ a Dept. of Civil Engineering, Faculty of Engineering and Arch., Ryerson Univ, Toronto, ON M5B 2K3, Canada b Dept. of Civil Engineering, Faculty of Engineering and Arch., Ryerson Univ., Toronto, ON M5B 2K3, Canada c Dept. of Civil and Environmental Eng., Shiraz University of Technology, Shiraz, Iran highlights  We use ESG and FBG sensors to investigate, shrinkage and creep of concrete.  The FBG is better than ESG for studying the time-dependent properties of concrete.  The specific creep of UHPC is less than that of HPC and NSC.  As concrete gets stronger, the shrinkage of concrete decreases.  The shrinkage strains of HPC and UHPC are about 80% and 65% of normal concrete. article info Article history: Received 10 July 2016 Received in revised form 23 January 2017 Accepted 25 January 2017 Keywords: Structural Health Monitoring (SHM) Normal Strength Concrete (NSC) High Performance Concrete (HPC) Ultra High Performance Concrete (UHPC) Electrical strain gauge (ESG) Fiber Bragg Grating (FBG) sensors abstract The research work reported in this paper is related to a Structural Health Monitoring (SHM) Project on a bridge in Ontario, Canada. It was recommended to use Fiber Bragg Grating (FBG) sensors to measure the dynamic response of the bridge and to measure creep and shrinkage in the piers of the bridge. The ran- dom decrement method is used to determine the deterioration through the dynamic parameters of the bridge as reported by Elshafey et al. [2] and Morsy et al. [15]. The measurements of creep and shrinkage strains are based on the FBG sensors reading that presented in the current paper. This investigation was necessary to ensure the creep and shrinkage strains are accurate based on a portable lab-top windows system integration system for the FBG readings. Normally, the lab FBG integration systems are very bulky and very expensive and fixed at lab location. However, due to the recent development in the electronic industry, it was possible to use a laptop portable computer system in this investigation. The system has been found accurate compared to the lab fixed equipment and it costs fraction of the expense. The test results of the measured creep and shrinkage showed an excellent correlation of the published data on Normal Strength Concrete (NSC), High Performance Concrete (HPC) and Ultra-High Performance Concrete (UHPC) using Fiber Bragg Grating (FBG) sensors. Results show that the FBG is a valid method for studying the time-dependent properties of concrete. Ó 2017 Elsevier Ltd. All rights reserved. 1. Introduction All concrete structures experience time-dependent deforma- tions known as shrinkage and creep. Shrinkage is the time- dependent deformation of concrete without the impact of external loads and it happens mainly due to loss of water during the drying process. Creep is the deformation of concrete under sustained stress over time. Therefore, the total strain of concrete specimens at any time is the combination of its initial elastic strain, shrinkage and creep [14]. Shrinkage and creep are important due to the fact that significant long-term characteristics are being affected by these two factors. In large scale structures, shrinkage and creep become more significant and they have the largest effect on crack- ing, structural deformation, pre-stressing forces and other damag- ing effects in concrete structures. Therefore, monitoring and prediction of shrinkage and creep in concrete structures have been considered by many researchers. A study was conducted by Mar- zouk [12] to compare the creep of normal and high strength con- crete. Gardner and Lockman [5] presented a design procedure for calculating the dry shrinkage and creep of Normal Strength Con- crete using the information available at design. Mertol et al. [13] monitored the shrinkage and creep of cylindrical and prism http://dx.doi.org/10.1016/j.conbuildmat.2017.01.084 0950-0618/Ó 2017 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail addresses: zyazdiza@ryerson.ca (Z. Yazdizadeh), hmarzouk@ryerson.ca (H. Marzouk), hadianfard@sutech.ac.ir (M.A. Hadianfard). Construction and Building Materials 137 (2017) 505–512 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat