Overgrinding of Portland cement brings excessive shrinkage and poor self-healing ability to concrete. In this paper, through the ultrasonic test and optical micrograph observation, the self-healing properties of concrete prepared by cement with different particle size distributions were studied. Besides, the effect of carbonation and continued hydration on self-healing of concrete was analyzed. Results show that, for the Portland cement containing more particles with the size 30~60 μm, the concrete could achieve a better self-healing ability of concrete at 28 days. For the two methods to characterize the self-healing properties of concrete, the ultrasonic test is more accurate in characterizing the self-healing of internal crack than optical micrograph observation. The autogenous self-healing of concrete is jointly affected by the continued hydration and carbonation. At 7 days and 30 days, the autogenous self-healing of concrete is mainly controlled by the continued hydration and carbonation, respectively. The cement particle size could affect the continued hydration by affecting un-hydrated cement content and the carbonation by affecting the Ca(OH)2 content. Therefore, a proper distribution of cement particle size, which brings a suitable amount of Ca(OH)2 and un-hydrated cement, could improve the self-healing ability of concrete.
For many years, researches have investigated concrete repair technologies including epoxy resin injection technology, bioremediation technology and self-healing technology. However, these repair methods have proven to be expensive and cumbersome to be carry out. A more recent technology electrochemical deposition, the focus of this paper emphases in a new way of healing concrete cracks that restores durability and mechanical strength of a concrete structure. Therefore, the emphasis of the research work reported here in is to prove the repair efficiency of the electrodeposition method by adding carbon fiber and graphene to the concrete. By analyzing the mass change of the concrete, total charge passed, crack width variation, ultrasonic waves, sediment composition and morphology, it was found that the cracks with width of 0.3-0.5 mm in samples healed within 20 days. The repair efficiency of samples mixed with carbon fiber and graphene were better than specimens without carbon fiber and graphene. Moreover, the mass increase rate of a concrete samples mixed with carbon fiber and graphene was 10.15 ‰, which is twice the mass of conventional concrete. The results of SEM and X-ray diffraction analysis showed that the samples mixed with carbon fiber and graphene produced more ZnO and that had a continuous compact structure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.