Natural Polymer-Based Hydrogel Incorporating Self Healing Mortar


Ertug M., Uzum O., Urkmez A. , Andic-Cakir O.

7th Asian Symposium on Polymers in Concrete (ASPIC 2012), İstanbul, Türkiye, 3 - 05 Ekim 2012, ss.377-386 identifier

  • Cilt numarası:
  • Basıldığı Şehir: İstanbul
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.377-386

Özet

In this study, the self healing capacity of mortars incorporating a natural polymer-based hydrogel (chitosan) as a healing agent is compared to control mortars without the healing agent. The hydrogels are placed into mortars after encapsulation. The aim of encapsulating the healing agent is to provide water proofness during the fresh state of mortars. The chitosan macrospheres (diameter approximate to l mm) were stabilized and encapsulated by a synthetic polimer and cement based insulation material provided from the market. Pre-trials have shown that the encapsulated hydrogel macrospheres have shown a considerable expansion after the capsules were torn. The method for observing the self healing mechanism is as follows: control and test series were cast and cured for 7 days in water at standard conditions, and then, a controlled pre-load is applied by three-point bending. The pre-loading causes controlled cracking at the lower mid points of the mortar specimens. Just after the pre-loading, the microphotographs of the cracks were taken by stereomicroscope and their ultrasonic pulse velocity values were determined. The specimens were then placed into air-tight containers and cured over water for a further 21 days. The ultrasound measurements were taken after curing and the microphotographs of the cracked samples were taken. The difference between the ultrasound measurements compared to control samples before and after curing and leaking of hydrogels into the cracks are the confirmations of the healing mechanism. The preliminary fmdings obtained from this study reveal promising results for incorporation of the chitosan hydrogel as a self healing agent for cementitious mixtures.