### A study of the natural self-healing of mortars using air-flow measurementsA study of the natural self-healing of mortars using air-flow measurements

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 Author Gagné, R. ♦ Argouges, M. Source SpringerLink Content type Text Publisher Springer Netherlands File Format PDF Copyright Year ©2012 Language English
 Subject Domain (in DDC) Technology ♦ Engineering & allied operations Subject Keyword Mortars ♦ Crack ♦ Self-healing ♦ Air-flow ♦ Permeability ♦ Air permeability ♦ Carbonation ♦ Expansive core ♦ Controlled cracking ♦ Building Materials ♦ Structural Mechanics ♦ Civil Engineering ♦ Operating Procedures, Materials Treatment ♦ Theoretical and Applied Mechanics ♦ Materials Science Abstract The aim of this research is to investigate the natural self-healing of mortars using air-flow measurements through a single crack of controlled geometry. Mortars were made with water–cement (W/C) ratios of 0.35, 0.45 and 0.60. For each type of mortar, three crack categories were created: 50 ± 15, 105 ± 15 and 220 ± 35 μm. Mortars were cracked at the age of 28 days and 6 months. Cracked mortars were stored in air at 23 °C and 100 % R.H. for up to 5 months to simulate the environmental conditions for open-air above-ground concrete structures. During the first month, the kinetics of self-healing is noticeably faster. The self-healing mechanism mainly involves carbonation and the formation of secondary hydration products in the crack volume. For fine cracks (50 μm), the self-healing rate is slow (5–10 μm/month). For larger cracks (>200 μm), the self-healing rate is faster (15–30 μm/month), as there is no space limitation for the formation of self-healing products and also because the effective crack opening remains high enough for the supply of external CO$_{2}$ and water. For crack openings higher than 300 μm, the final natural self-healing level is less than 20 % after 5 months. For the mortar tested, age at the time of cracking only plays a minor role on self-healing kinetics. ISSN 13595997 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 2012-04-24 Publisher Place Dordrecht e-ISSN 18716873 Journal Materials and Structures Volume Number 45 Issue Number 11 Page Count 14 Starting Page 1625 Ending Page 1638