ABSTRACT
A large steel industry in located in Isfahan, Iran, which is situated near by the site of a number of large hydraulic/hydropower projects. A laboratory research study was undertaken to investigate the effect of ground blast-furnace slag on RCC. Working time, allowable delay between mixing and compaction, could be a major concern in some projects when the site is difficult and/or the contractor is not fully developed. The effect of ground blast-furnace slag on allowable working time of RCC was the main aim of the research. In addition, the effect of slag on the strength of RCC at different age was also studied. A number of cylindrical laboratory specimens were prepared. Most specimens were vibrated using Vebe test apparatus for the compaction of RCC. To study the effect of compaction methods, a number of samples were also compacted with the same type of hammer that is used for the modified Proctor test. The amount of cementitious content (Portland cement plus slag) was varied from 75 to 300 kg/m3. Slag content varied from 25 to 90 percent. The compaction of samples deliberately delayed for 30, 45, 60, 90 & 120 minutes to study the effect of working time. It was concluded that slag content has an important effect on working time. It is a high content of slag could allow a longer allowable working time for RCC. Those samples were constructed at optimum water content using hammer presented a higher strength than those constructed by VB apparatus. When a high content of slag is used, the increase of slag would slightly decrease the strength. However, the rate of strength reduction due to the increase of slag is not high when a high content of slag is used.
