Microscopic observations of self‐healing products in calcareous fly ash mortars

The results of microstructural characterization of mortars containing fly ash class C (High Calcium Fly Ash) from combustion of lignite are presented. The evaluation of the microstructure was performed using scanning electron microscope, optical, and confocal microscope. The tested beams were bent till the crack and microcracks opening, which were healed during the different curing time. The results showed that the replacement of cement with fly ash class C influenced the process of crack healing. The addition of HCFA, at both 30% and 60%, speeds up the self‐healing process in cracks and particularly in micro‐cracks. In the research, the completely filling up of the cracks by new phases has not been observed, only the beginning of such process has been noticed. Microsc. Res. Tech., 78:22–29, 2015. © 2014 Wiley Periodicals, Inc.

[1]  S. Diamond.  The microstructure of cement paste and concrete - a visual primer , 2004 .

[2]  En-Hua Yang,et al.  Autogenous healing of engineered cementitious composites at early age , 2011 .

[3]  V. S. Ramachandran,et al.  Handbook of Analytical Techniques in Concrete Science and Technology: Principles, Techniques and Applications , 2000 .

[4]  Björn Johannesson,et al.  A review : Self-healing in cementitious materials and engineered cementitious composite as a self-healing material , 2012 .

[5]  D. Jóźwiak-Niedźwiedzka,et al.  CARBONATION OF CONCRETES CONTAINING CALCAREOUS FLY ASHES , 2014 .

[6]  Tomoya Nishiwaki,et al.  Self-Healing Capability of Fiber Reinforced Cementitious Composites , 2011 .

[7]  Hubert Rahier,et al.  Influence of mix composition on the extent of autogenous crack healing by continued hydration or calcium carbonate formation , 2012 .

[8]  H. Jonkers,et al.  Recent advances on self healing of concrete , 2010 .

[9]  Carola Edvardsen,et al.  Water Permeability and Autogenous Healing of Cracks in Concrete , 1999 .

[10]  T. Kishi,et al.  Self healing properties with various crack widths under continuous water leakage , 2009 .

[11]  S. Bang,et al.  Calcite precipitation induced by polyurethane-immobilized Bacillus pasteurii. , 2001, Enzyme and microbial technology.

[12]  Barbara Lubelli,et al.  Self-healing of lime based mortars: microscopy observations on case studies , 2011 .

[13]  H. Reinhardt,et al.  Permeability and self-healing of cracked concrete as a function of temperature and crack width , 2003 .

[14]  Zbigniew Ranachowski,et al.  Application of Acoustic Emission Method to Determine Critical Stress in Fibre Reinforced Mortar Beams , 2012 .

[15]  Jan Olek,et al.  Characterization of High-Calcium Fly Ashes and Their Potential Influence on Ettringite Formation in Cementitious Systems , 1999 .

[16]  Carolyn M. Dry,et al.  Procedures developed for self-repair of polymer matrix composite materials , 1996 .

[17]  Victor C. Li,et al.  Self-Healing of Microcracks in Engineered Cementitious Composites (ECC) Under a Natural Environment , 2013, Materials.

[18]  J. Olek,et al.  Characterization of pore solutions expressed from high-calcium fly-ash–water pastes , 2001 .

[19]  Toshiharu Kishi,et al.  Crack Self-healing Behavior of Cementitious Composites Incorporating Various Mineral Admixtures , 2010 .