Determination of Self-Healing Performance of Cementitious Composites Under Elevated CO2 Concentration by Resonant Frequency and Crack Opening Measurements

Abstract

Global warming is a phenomenon that incontrovertibly affects daily lives of human beings in almost all aspects. Definitely, construction industry, especially concrete as most commonly used construction material, is not exempt from the effects of global warming. Nevertheless, there is a lack of information on how the change in atmospheric conditions influences self-healing behavior of cementitious materials. This research examines the impact of increased CO2 concentrations in the atmosphere on the self-healing capability of cementitious materials in terms of resonant frequency and crack opening measurements. For this purpose, to clearly disclose the effect of tremendous increase in the environmental CO2 concentration as a result of global warming, Engineered Cementitious Composites (ECC) which possess advanced intrinsic self-healing capability were employed. For this purpose, sound and pre-cracked ECC specimens containing fly ash and ground granulated blast furnace slag were tested by resonant frequency after 28 days of initial curing up to 28 + 90 days with 15 days intervals and crack openings were observed for each testing age. Moreover, in order to accelerate the capture of CO2 from the environment, a third ECC mixture was prepared by adding Ca(OH)2 to the ECC mixture incorporating fly ash. The results showed that CO2 present in the environment can improve the self-healing behavior of ECC mixtures, which is a promising finding in terms of environmental concerns. Possibility of capturing and decreasing the CO2 from the atmosphere by self-healing mechanism will make the ECC a more environmentally friendly construction material additional to its superior technical properties.