LAUSR

Roller-compacted concrete or RCC is a dry concrete that requires compaction in order to reach its final form. Its consistency is usually overlooked due to its inconsistency and lack of subjective nature. To work with this concrete, however, proper consistency is necessary for supporting the compacting machine and minimizing compaction energy. Vebe time is used as consistency measurement due to RCC’s dryness. Vebe time ranged from 30 to 75 seconds is considered to be appropriate consistency for RCC in pavement application. The purpose of this study is to determine the effect of aggregate gradation, water content, admixtures and time on RCC’s consistency for pavement application. It was found that Vebe time decreased when water content increased and increased when sand by aggregate ratio or the amount of fine aggregate increased. The workable time of normal RCC mixture (an optimal mixture) was found to be less than 50 minutes. Poly Naphtalene Sulfonate superplatiscizer or PNS was discovered to be very effective in lowering down Vebe time and maintaining it. 0.3% of this admixture was learned to extend the working time up to four hours without influencing RCC’s compressive strength.