SUBSTANCE PENETRATION PROPERTY OF THE CONCRETE USING WITH CaO・Al₂O₃ AGGREGATE

Abstract

The aggregate composed primarily of CaO, Al₂O₃（CaO・Al₂O₃ aggregate）generates hydroculmite by hydrating with calcium hydroxide which is a cement hydrate, and reacting and generate Friedel salt when a chloride ion acts. When the calcium aluminate is used for concrete as aggregate, a hydration was occurred at the aggregate surface. As a result, the possibility that a transition zone of concrete was modified by using the CaO・Al₂O₃ aggregate was suggested. In this research, physical properties and substance penetration property of the concrete which using with calcium aluminate aggregate were examined. Regarding the strength development property, it was confirmed that the concrete using with CaO・Al₂O₃ aggregate showed higher compressive strength compare with the concrete using with natural aggregate but there was not confirmed interrelation between compressive strength and absorption property of concrete. This was considered to be caused by generation of Hydroculmite and Friedel’s salt which were generated by the reaction of CaO・Al₂O₃ aggregate. By the result of SEM-EDS, an aggregate interface became the dense with the concrete using the CaO・Al₂O₃ aggregate in comparison with concrete using the natural aggregate, and it was confirmed that a different hydrate was generated inside and outside the outer layer of the CaO・Al₂O₃ aggregate.