Fundamental Properties and Self-Healing Performance of Repair Mortar with Solid Capsules Made Using Inorganic Reactive Powder

Abstract

Self-healing cement composites are generally produced by using materials such as inorganic powders, bacteria pellets, and microcapsules. Among them, inorganic powder-type healing materials tend to decrease in healing performance over time because they react relatively quickly. Accordingly, this study encapsulated self-healing inorganic reactive powders in solid capsules (SC) in order to delay their reaction. The capsule surface was coated with a membrane to prevent moisture from permeating it. SC were utilized to provide the self-healing effect to the repair mortar. SC were mixed at three rates (0%, 5%, and 10%) by the binder mass of the repair mortar. The fundamental properties, including rheology, table flow, strength, and length change, and the self-healing performance of the self-healing repair mortar mixes were investigated. It was found that the rheological and mechanical properties of the repair mortar decreased slightly as the amount of SC increased. On the other hand, for a crack width of 0.25 mm and crack inducing age of 28 days, the healing performance of repair mortar specimens containing SC was at least 20 pt% better than that of plain repair mortar after a healing period of 28 days.

Effects of Capsule Type on the Characteristics of Cement Mortars Containing Powder Compacted Capsules

“…In the water permeability test, the specimen was split after 28 d of age, and 0.3 mm silicone sheets were placed on both ends of the specimen to maintain the crack width. After fixing the specimen using a clamp, a water permeability test ( Figure 4 ) was performed at each age according to previous studies [ 11 , 15 , 29 , 30 ].…”

“…Among the discussed self-healing technologies, the encapsulation of cement-based materials is advantageous, specifically because large amounts of self-healing material can be contained in a capsule and released at the cracked site for a targeted reaction [ 15 , 16 ]. When the cementitious self-healing material is released from the crack area, it can react with the pore water in the cement composite to form hydrates, thereby producing a healing effect.…”

“…This study produced a powder compacted capsule (PCC) using the droplet and blended manufacturing methods [ 15 , 25 ] to encapsulate a cementitious material. Moreover, the mechanical properties of the PCC were evaluated.…”

Self-Healing Mechanical Properties of Selected Roofing Felts

“…An improvement in SH abilities and a simultaneous reduction in shrinkage using microcapsules is presented in [ 14 ]. Concrete and mortars with SH properties, with the possibility of the cracks’ closure, are presented in [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. The methodology for evaluating concrete’s self-healing performance is presented in [ 23 ].…”

Study on Shrinkage Properties of Repairing Mortar Modified by Basalt Fiber

“…Concrete damage has always been a common problem in concrete structures. In order to restore the function of damaged concrete structures, cement-based materials such as concrete or mortar have been usually used as repairing materials (Zailani et al 2020, Yang et al 2020, Xue et al 2021, Oh et al 2022. Cement-based material is one of the most widely used building materials in the world, which has both advantages, such as easy access of raw materials, easy production and construction, and disadvantages, like high shrinkage (Zhang et al 2021), easy cracking (Szeląg 2020) and low compressive strength (Kasal and Vítek 2022).…”