STUDIES ON BLAST-FURNACE-SLAG AGGREGATES FOR CONCRETE - 1. PROPERTIES OF BLAST FURNACE SLAG AGGREGATES AND SLAG AGGREGATE CONCRETE.

In June 1977, a new Japanese Industrial Standard, JIS A 5011 ″Air-Cooled Blast Furnace Slag Aggregates for Concrete″ was established. This report describes physical properties of air-cooled blast furnace slag aggregates and workability and mechanical properties of slag aggregate concrete. Physical properties of air-cooled blast furnace slag aggregates produced in three iron works were a little inferior to those of crushed sandstone for concrete, but met all the requirements of JIS A 5011. Workability of slag aggregate concrete was the same as that of crushed sandstone aggregate concrete, so that mixed proportions of slag aggregate concrete can be designed in the same way as with conventional crushed stone aggregate concrete of the same workability. Compressive, tensile, flexural, shear and bond strength values and the modulus of elasticity of slag aggregate concrete were 5 to 20% smaller than those of crushed sandstone aggregate concrete, but relations between compressive strength and other strength values were the same. Reduction of compressive strength and the modulus of elasticity of slag aggregate concrete after heating at temperatures of 100 degree C and 300 degree C for 60 days was slightly larger than those of crushed sandstone aggregate concrete. Drying shrinkage of slag aggregate concrete was 10 to 20% smaller than that of crushed sandstone aggregate concrete at an age of as long as one year, because the water absorption of slag aggregates was 2 similar 3% larger than that of sandstone. Creep strain of slag aggregate concrete under the compressive creep test up to 270 days under a stress of 130 kg/cm**2 was slightly larger, while creep factors were 10% smaller than those of crushed sandstone concrete.