Thesis defence L. Lu: self-healing (1)

25 September 2018 10:00 - Location: Aula, TU Delft - By: webredactie

Novel routes to polymer-based self-healing systems for cementitious materials. Promotor 1: Prof.dr.ir. H.E.J.G. Schlangen (CiTG); Promotor 2: Prof.dr. N. Han (Shenzhen U.).

Cementitious materials are the most widely used construction materials on this planet. However, due to its heterogeneous and quasi-brittle nature, they are susceptible to many sources of damage during their entire service life. Although man-made repair can prolong the service life of reinforced concrete structures, it gives rise to large amounts of rehabilitation work, associated costs and waste of resources.

To decrease the frequency of maintenance and prolong the life-span of concrete structure, the self-healing concept was introduced to cementitious materials and has already shown its great application potential in the past decade. In this concept, self-healing additives are first blended with fresh mortar. When the cracks encounter the additives, the self-healing additives will be triggered and then react to the environmental change accordingly.

However, up to date, the available self-healing additives for cementitious materials are not able to deal sufficiently enough with all the diverse situations. The self-healing potential that the self-healing agent brings is not very clear. The size of cracks can vary from the micrometer to millimeter level in real situations. Nevertheless, strategies for multi-scale crack healing are still lacking. Based on these problems, in this thesis, two different types of self-healing additives, microencapsulated adhesive and water swelling rubber particles (WSRPs) were designed and prepared particularly for micro-scale (<500µm) and meso-scale (>500µm) cracks in cementitious materials. The healing effect and potential of using microcapsule-based self-healing system was evaluated and predicted through both experimental and numerical methods. The water sealing function to meso-scale cracks by applying WSRPs was characterized and monitored using X-ray Computed Tomography (XCT) technology and a water flow rate recording device. It is believed that this work can give insight into the future implementation of self-healing strategies in practical cementitious materials application.

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