Advances in Self-healing Cementitious Materials

Abstract

PrefaceThis special issue is aiming at summarizing recent progress in self-healing cementitious materials and at motivating further development in the relevant research. It took a long time since the efforts to develop self-healing materials working as intelligent materials drew strong attention worldwide in the research communities. Research and development of self-healing performance have been progressing on varieties of materials including metals, non-metals, inorganic and organic materials, and composite materials. Particularly for cement-based materials, based on the background of epoch-making ideas and existing research results, it has become possible to introduce some self-healing functions and their combined mechanisms. These self-healing cementitious materials have potentials to renovate existing structural designs and maintaining schemes and contribute to service life extension and environmental impact reduction. We expect this special issue could support to realize the potential.This special issue was worked out under a strong support of JCI Technical Committee on Self-healing / Repairing Technology in Cement-based Materials (JCI TC-091) chaired by Prof. S. Igarashi, Kanazawa University. This committee's activities included 1) quantitative evaluation of self-healing performance such as water leakage control and loading damage recovery, 2) investigation into self-healing mechanism, and 3) application of non-destructive test to identify self-healing results. Committee members of the TC are listed below.Koichi Maekawa, Editor-in-Chief of ACT TC-091 committee members AbstractReinforced concrete (RC) structures in marine environments are generally affected by harsh marine environmental actions, resulting in early performance degradation mainly due to chloride-induced deterioration. In such conditions, corrosion of rebar progresses rapidly, and also the cross-sectional area of rebar is reduced and consequently structural performance of RC structures will be degraded. In contrast, the surface of concrete structures is often covered with many marine sessile organisms under marine tidal and submerged conditions. These marine sessile organisms have been empirically known to enhance the durability of concrete though the effectiveness is not appropriately evaluated. This paper describes the long-term resistance of concrete with marine sessile organisms to chloride ion penetration in concrete. The effect and its sustainability of marine sessile organisms on chloride ion penetration in concrete were investigated through field exposure tests and laboratory tests. From the test results, the basal membrane, which is a matrix of marine sessile organisms, adheres to concrete strongly on a long-term basis though some gaps between concrete and the basal membrane can be observed. In addition, experimental results and simplified simulation clarified that the attachment of marine sessile organisms can enhance the long-term resistance of concrete to chloride ion penetration.