jailcd2019-052: Development of Blast Furnace Slag Coarse Aggregate with Low Water Absorption

Abstract

The authors developed the blast furnace slag continuous solidification process in order to reduce the water absorption of BFG to 1 % or less. The molten slag is poured into mold, and the slag is solidified at the thickness of 20 mm to 30 mm before the gas in the slag is generated and produced. The process results in the reduction of the porosity of slag. A pilot plant was constructed, and production of BFG under 1% became possible using this plant. By using this process, the new BFG had water absorption has about 0.66%. In order to evaluate the concrete applicability of the new BFG such as workability, the pumping performance, change over time in the air content, surface finish and properties of concrete joints were evaluated. The concrete of dense BFG coarse aggregate has the same workability, strength and durability as that of limestone coarse aggregate. In the test construction of actual plant, we confirmed that there is no problem with pump ability, filling property to formwork and surface finish. Therefore, the conclusion was reached that the concrete performance of new BFG are the same as that of limestone aggregate.