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The use of superabsorbent polymers as a crack sealing and crack healing mechanism in cementitious materials

Author(s): D. Snoeck, K. Van Tittelboom, N. De Belie
Paper category: Conference
Book title: Concrete Repair, Rehabilitation and Retrofitting III (ICCRRR)
Editor(s): M.G. Alexander, H.-D. Beushausen, F. Dehn, P. Moyo
Print ISBN: 978-0-415-89952-9
Publisher: Taylor & Francis Group
Pages: 58 – 59
Total Pages: 2
Language: English

As concrete cracks due to its low tensile strength and as harmful fluids may migrate into these cracks, the durability of concrete is endangered if no proper treatment or manual repair is applied. To address this need, this research focusses on the use of superabsorbent polymers (1) to seal cracks from intruding potentially harmful substances and (2) to heal the crack due to further hydration and precipitation of calcium carbonate. The first focus relies on hindering the fluid flow by swelling of superabsorbent polymers after they are exposed to a humid environment. The sealing capacity was measured by means of water permeability tests and through visualization of permeability tests by neutron radiography. Superabsorbent polymers are able to seal cracks and thus allow a recovery in water-tightness as a decrease in permeability is noticed. The second focus relies on healing of small cracks in fibre reinforced cementitious materials, restoring the mechanical properties. The regain in mechanical properties was analyzed by four-point-bending tests and the crack closure was microscopically monitored. Cracks close through the combination of further hydration of unhydrated cement particles, precipitation of calcium carbonate and activation of the pozzolanic reaction of fly ash. Desorption of superabsorbent polymers triggers healing in the vicinity of crack faces and cracks up to 130 μm were able to close completely in wet/dry cycles due to the precipitation of calcium carbonate. Mortar samples containing superabsorbent polymers even showed partial healing when stored under a relative humidity of more than 60%. In this way, a smart cementitious material which is reliable and independent from the conditions is acquired.

Online publication: 2014
Publication Type: abstract_only
Public price (Euros): 0.00