Improved mixture composition for early-opening heat-conductive concrete

This study proposes an improved mixture composition for early-opening heat-conductive concrete for pavement. The formulation has a snow-melting function, with a compressive strength of at least 21 MPa after 3 h of curing. The mix variables were the proportions of graphite, coke replacement, coarse aggregate size and type of metallic material. Heating properties were evaluated as a function of these variables. The heating evaluation was performed by placing a cylindrical (diameter: 100 mm, length: 200 mm) specimen in a fixing jig, attaching a copper plate to each end of the specimen and passing a 220 VAC electric current between the copper plates. These experiments demonstrated that coke had a better heating effect than graphite, and that heating improved when metallic materials were used. Additionally, using a small (10-mm) aggregate provided better heating properties than a large (13-mm) aggregate.