Self-healing performance of engineered cementitious composites through the use of nano-silica

Author(s): Oğuzhan Öztürk, Gürkan Yıldırım, Ülkü S. Keskin and Mustafa Şahmaran
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials, Systems and Structures (SMSS2019) New Generation of Construction Materials
Editor(s): Marijana Serdar, Nina Štirmer, John Provis
ISBN: 978-2-35158-217-6,
Vol 1. ISBN: 978-2-35158-223-7
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 622-629
Total Pages: 8
Language : English

Abstract: The COST Action CA15202 – Self-healing As preventive Repair of COncrete Structures (SARCOS), has gathered European researchers active in the field of self-healing cement- based materials and within this context has secured the financial support of the European Commission. Within the frameworks of different working groups of SARCOS, several review papers focusing on self-healing cementitious materials have already been published. Engineered Cementitious Composite (ECC) is reported to be one of such promising materials which combine superior mechanical and durability properties. These superior characteristics make the material a favorable preference for various infrastructures. ECCs exhibit strain/deflection-hardening behavior by forming multiple micro-cracks under severe loading conditions unlike normal or conventional fiber reinforced concrete. It is also known that autogenous self-healing is an inherent property of ECCs and the extent of intrinsic self-healing is substantially dependent on crack widths. This behavior can provide decrements of detrimental substance ingress in structures so that longer service life can be possible. However, studies available in the literature reported that success of self-healing becomes limited when larger cracks and repetitive mechanical loadings take place. Here, efforts were made to confront the abovementioned limitations of intrinsic self-healing of ECC compositions with nano-silica. Results of experiments revealed that nano-silica utilization triggered more robust and expedited self-healing products in the cracks of cementitious system along with unhydrated cement particles that also contributed for higher strength grades. Micro analysis indicated that wider cracks (>250 μm) can be fully closed by nano silica incorporation in ECCs. In addition, preloaded nano-silica incorporated ECC specimens attained permeability properties similar to uncracked specimens. It can be concluded that autogenous self-healing of ECCs can be further improved in terms of both mechanical and transport properties with the use of nano-silica which tailors the microstructure and contributes to enhanced healing mechanisms of conventional ECC mixtures.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00