Self-healing performance of cement mortar mixed with pulverized clinker and inorganic admixture

¹ Construction Technology Research Center, Construction Division, Korea Conformity Laboratories, 199, Gasan Digital 1-ro, Geumcheon-gu, Seoul, 08503, Republic of Korea
² Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Faculty of Engineering and Architecture, Ghent University, Technologiepark Zwijnaarde 60, B-9052 Gent, Belgium
³ Department of Civil, Architectural and Environmental System Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea

Abstract

This study evaluated the mechanical properties and self-healing performance of cement mortar containing pulverized clinker, calcium sulfoaluminate (CSA), and Na₂SO₄. Mechanical properties of cement mortar were investigated by measuring compressive strength, and sealing efficiency were evaluated by a hydrostatic permeability test and a nitrogen gas diffusion test. Moreover, the healing products adhering to the cracks were visually observed with an optical microscope and a scanning electron microscope (SEM). As a result, incorporating pulverized clinker with mineral admixtures increased the 3- and 28-day strength by approximately 20%. There was a difference in the sealing efficiency depending on the evaluation method. The sealing efficiency of the gas diffusion test was underestimated due to the difference in characteristics according to the type of medium passing through the crack. Nevertheless, when the inorganic additive was mixed with cement mortar, CaCO₃ precipitated as the healing product within 0.3 mm cracks and improved self-healing performance.