Glass encapsulated minerals for self-healing in cement based composites

Abstract

This study presents the encapsulation of mineral compounds as healing materials for cement-based composites. Three liquid (sodium silicate, colloidal silica and tetraethyl orthosilicate) and one powdered (magnesium oxide) minerals were encapsulated in thin walled soda glass capsules. Load regain was obtained for samples healed under three different curing regimes; ambient conditions, high humidity exposure or immersed in water. Water immersion resulted in crack area closure that ranged from 85% to 100% for all mineral treated samples. The measured reduction in both sorptivity and intrinsic gas permeability varied from 18% to 69% depending on the measured parameter and mineral type. Sodium silicate and colloidal silica presented with the best and more consistent response in all applied measurements, both in terms of load and durability recovery. These results demonstrate how self-healing can be achieved by utilising cost effective mineral compounds which are also compatible with the host cementitious matrix.

Polymeric microcapsules with switchable mechanical properties for self-healing concrete: synthesis, characterisation and proof of concept

“…When in contact with the calcium hydroxide present in concrete, sodium silicate interacts chemically to produce crystalline and amorphous products that can promote healing. Recent results showed that liquid sodium silicate considerably improved the self-healing efficiency in cracked mortar specimens [27]. Recent attempts to produce microcapsules for cement-based materials include the use of polymeric microcapsules for encapsulating sodium silicate [28,29].…”

A Review: Novel Routes towards the Realization of Self-Healing Function in Cementitious Materials

“…The benefit of using polymer as shell materials is it has good sealing function to the healing agent, which is believed as a crucial factor for most of healing agent that would lose effect when it encounters with high alkaline solution. Inorganic microcapsule is another category of microcapsules that employing inorganic materials such as silica particles [38], glass capsules [39], expanded clay [4] as shell materials. Due to the similar properties of materials, the advantage of inorganic microcapsules is the relatively good bonding strength with cementitious matrix, which is believed to have a influence on the trigger efficiency of microcapsules.…”

Epicrystal modification of construction composites of different purpose with application of granulated nanostructured aggregate.

“…В данном случае контактный слой включает два независимых компонента -контактную зону заполнителя, прилегающую к цемент-ному камню, и контактную зону цементного камня около поверхности заполнителя. Поиск путей решения данной проблемы является акту-альным направлением исследований как в России, так и за рубежом [12][13][14][15][16].…”