Influence of expansive minerals on the self-healing of cement paste and mortar systems

Qureshi, Tanvir; Al-Tabbaa, Abir

Abstract

Expansive minerals have great prospects for improving the self-healing capacity of concrete. Once a crack start propagating, an embedded unhydrated expansive mineral could hydrate and expand hence bridging and healing the cracks. This study investigates the self-healing of Portland Cement (PC) based mortar system using MgO, bentonite clay and quicklime minerals. Firstly, expansive minerals optimum mix proportions for improving the autogenous self-healing capacity of cement paste were investigated. Secondly, expansive minerals were encapsulated within the glass tube capsules and embedded into the mortar prisms for investigating self-healing. The healing efficiency was compared in three different curing conditions (ambient, high humidity, and immersed in water) using mechanical strength recovery, crack sealing percentage, and water absorption through cracks (immersed only). Further microstructural investigation was carried out on self-healing materials for characterising self-healing materials using FT-IR, XRD, and SEM. Promising self-healing performance was found in the samples stored in immersed condition, while limited healing happens in high humidity following by the least performance in the ambient condition. Strength recovery and water tightness were found much higher in the capsule containing samples. Several cracks up to 500 µm had effectively sealed within 7 days in the samples containing optimum self-healing cement mix at immersed healing state. Superficial crack sealing compounds were dominantly calcium carbonate based crystals, although different minerals influenced formation of different types of self-healing materials particularly in the inner crack cross-section.

Citation

Qureshi, T., & Al-Tabbaa, A. (2015). Influence of expansive minerals on the self-healing of cement paste and mortar systems. In Fifth International Conference of Self-healing Materials, Durham, NC (U.S.A.)

• Start Date: Jun 22, 2015
• Acceptance Date: Jan 1, 2015
• Publication Date: 2015
• Deposit Date: Oct 3, 2020
• Book Title: Fifth International Conference of Self-healing Materials, Durham, NC (U.S.A.)
• Public URL: https://uwe-repository.worktribe.com/output/6726615
• Publisher URL: http://icshm2015.pratt.duke.edu/icshm-2015-extended-abstracts.html