Title: Characterisation of self-healing efficiency of calcium nitrate microcapsules for concrete applications

Authors: Ala G. Abu Taqa; Mohammed Al-Ansari; Ahmed Senouci; Marwa M. Hassan; Ahmed Shaat; Mohamed O. Mohsen

Addresses: Department of Civil and Architectural Engineering, Qatar University, P.O. Box 2713, Doha, Qatar ' Department of Civil and Architectural Engineering, Qatar University, P.O. Box 2713, Doha, Qatar ' Department of Construction Management, University of Houston, TX 77204-4020, USA ' Department of Construction Management, Louisina State University, Baton Rouge, LA 70803, USA ' M Z & Partners Architectural & Engineering Consultancy, P.O. Box 5785, Doha, Qatar ' Department of Civil and Architectural Engineering, Qatar University, P.O. Box 2713, Doha, Qatar

Abstract: This study presents characterisation of concrete samples containing 0.75% by cement weight of modified calcium nitrate self-healing microcapsules. The phased array ultrasonic testing method was used to investigate the healing efficiency of calcium nitrate microcapsules in concrete. The method is a novel non-destructive testing technique that is commonly used for detecting the defects in welding. Concrete beams were prepared from the control mix (without microcapsules) and mixes containing 0.75% by weight of cement of calcium nitrate microcapsules. After 28 days of moist curing, the phased array ultrasonic images of all beams were captured before loading, after applying 60% of the ultimate flexural load, and after 3 and 7 days of accelerated healing. Moreover, scanning electron microscopy images taken from fractured surfaces of the beams that were loaded up to failure before healing were compared to those of the beams that were healed for 7 days and loaded up to failure.

Keywords: calcium nitrate microcapsules; self-healing concrete; calcium nitrate microcapsules; phased array ultrasonic testing; scanning electron microscopy.

DOI: 10.1504/IJMMP.2019.099908

International Journal of Microstructure and Materials Properties, 2019 Vol.14 No.3, pp.238 - 255

Received: 23 Apr 2018
Accepted: 22 Nov 2018
Published online: 27 May 2019 *

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