Effect of water/binder ratio and temperature on the hydration heat and properties of ternary blended cement containing slag and iron tailing powder

The effects of water/binder ratio and temperature on hydration heat and properties of ternary blended cement containing slag and iron tailing powder were investigated. The hydration heat was determined by isothermal calorimeter. The Ca(OH)2 content of ternary hardened paste was obtained based on the thermogravimetric results. The microstructure and compressive strength development were also analyzed. Partial substitution of iron tailing powder by slag reduces the early-stage exothermic rate, but increases the cumulative hydration heat at later-stage hydration. The high temperature dramatically increases exothermic rate and cumulative hydration heat, especially for ternary blended cement with large amount of slag. The addition of high quantity of iron tailing powder negatively affects properties development of blended cement. But partial substitution of iron tailing powder by slag increases bound water content, reduces Ca(OH)2 content, refines pore structure, densifies structure and finally improves compressive strength, especially at low water/binder ratio. The early high temperature curing results in poor properties of blended cement containing high quantity of iron tailing powder, but it is advantageous to the properties development of ternary blended cement containing slag and iron tailing powder.