Mechanical Properties and Durability of Concretes Manufactured using Pre-coated Recycled Fine Aggregate

• Main Authors: Bo-Sheng Syu, 許博勝
• Other Authors: Cheng,An
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/9d5z2r

碩士 === 國立宜蘭大學 === 土木工程學系碩士班 === 103 === This study investigated the mechanical properties and durability of concrete produced using recycled fine aggregate (RFA) pre-coated with fly ash, slag, and a polymer solution (PVA). We investigated the physical and microscopic properties of fresh concrete, while adjusting several of the fabrication parameters, such as the constituent make up and thickness of RFA pre-coatings. The study is divided into two parts. The first part involves mortar testing in which the RFA used for coating had a water/cement ratio of 0.5 and fly ash, slag, and PVA viscosity of 5~6cps, 21~26cps, 25~30cps, or 44~50cps. In these tests, 100% of the natural fine aggregate was replaced by RCA. The second part of the study involved the mixing of concrete with 25% FRA, which was respectively coated with fly ash, slag, or PVA at a viscosity of 44~50cps. In these tests, the water/cement ratio was either 0.4 or 0.6. The major findings in this study are summarized as follows：Coating RFA coated with fly ash and PVA was shown to increase flow in the fresh concrete; however, the coating of RFA with slag resulted in a slight decrease in flow. Coating RFA with slag was shown to improve the compressive and splitting strength to a greater degree than that achieved by coating RFA with fly ash and PVA. The mechanical properties of concrete mixed with slag were shown to increase with the thickness of the coating. Coating RFA with slag was also shown to enhance the durability of the concrete, regardless of the water/cement ratio.