Autogenous healing

Another major benefit of incorporating lime into mortars is that it confers autogenous healing of cracks. Cracking occurs for a variety of reasons both before, during and after the setting of the mortar. The formation of cracks, both at the mortar-masonry interface and within the mortar reduces the strength of the masonry unit and increases water penetration. 

The proven excellent durability of lime-based renderings is due partly to the above properties and partly to the autogenous healing properties conferred by... 

Edvardsen, C. (1999). Water permeability and autogenous healing of cracks in concrete, ACIMaterials Journal, 4 448 54. 

Yang, Y, Lepech, M.D., Yang, E.H. and Li, V.C. (2009). Autogenous healing of engineered cementitious composites under wet-dry cycles. Cement and Concrete Research, 39 382-390. 

The phenomenon of self regeneration of cracks in cement-based matrices, or so-called autogeneous healing, has been known for a long time. D. A. Abrams first published remarks on self-healing of cracks in reinforced concrete bridge elements exposed to external climatic influences over three years. He confirmed that under much higher loads new cracks opened but those previously healed did not re-open, Abrams (1913). 

Gray, R. J. (1984) Autogenous healing of fibre/matrix interfacial bond in fibre-reinforced mortar. Cement and Concrete Research, 14 315-17. 

Neville, A.M. (2002) Autogeneous healing - a concrete miracle Concrete International, 24(11) 76-82. 

The results obtained have shown that it is possible to determine the autogeneous healing effect by means of the acoustic emission method. For instance, figures 1 and 2 show the results obtained for the primary load 150 kN and 200 kN, respectively. In both of these figures the total AE counts are plotted against the load for different pauses in loading. 

It may be observed that when the primary load is rather small and when the period between loading and reloading increases then there is a distinct tendency to a considerable autogenous healing of the concrete structure. For higher values of primary loading the capability of this phenomenon significantly decreases. 

Acoustic emission permits to determine the extend of autogenous healing of plain concrete. 

Lauer, Kenneth R. and Slate, Floyd 0., Autogenous healing... 

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