Combinations of Pozzolans and Ground, Granulated, Blast-Furnace Slag for Durable211 Hydraulic Cement Concrete

摘要

Hydraulic cement concretes were produced using pozzolans and ground, granulated,211u001eblast-furnace slag (slag) to investigate the effect of these materials on 211u001edurability. The pozzolans used were an ASTM C 618 Class F fly ash with a low lime 211u001econtent and a dry, densified silica fume. The slag was an ASTM C 989 Grade 120 211u001ematerial. Concretes with a fixed cementitious materials content of 377 kg/cu m 211u001eand water-to-cementitious materials ratio (w/cm) were produced with an ASTM C 150 211u001eType I/II cement and pozzolans or slag. The following replacement levels were 211u001eused: fly ash; 0, 15, 25, and 35 percent; and slag; 25, 35, 50, and 60 percent. 211u001eConcretes were also produced by combining small amounts of silica fume with small 211u001eamounts of fly ash or slag. The concretes were evaluated for strength, electrical 211u001eresistance (ionic transport, permeability), drying shrinkage, resistance to 211u001efreezing and thawing were compromised by high replacement levels of fly ash or 211u001eslag, although the use of a constant w/cm may have exaggerated these responses. 211u001eConcrete durability, as indicated by electrical resistance and resistance to ASR, 211u001ewas greatly improved by increasing the pozzolan or slag content. Use of ternay 211u001eblends produced the desired property levels while maintaining the necessary 211u001edurability characteristics.