INFLUENTA FILERELOR ASUPRA PROPRIETĂTILOR BETONULUI AUTOCOMPACTANT

The work aim was to study the influence on limestone filler (L) and volcanic tuff filler (VT) on the self compacted concrete (SCC) main properties referring to workability and compression strengths time-evolution. The using fillers addition to SCC is due to its positive influence on viscosity and segregation resistance. The SCC workability is defined by the two rheological parameters, a low yield stress and an adequate plastic viscosity. SCC workability testing was carried out. These rheological parameters were described by flow ability measured by slump flow test and flowing rate, measured by T 500 slump flow and V funnel test The yield stress was described by SCC spreading diameter and the plastic viscosity was evaluated as SCC flow resistance measured by flow time, T 500 or V funnel time. Also, was measured passing ability (L-box) and segregation stability (visual stability Index). The rheological properties (slump-flow) of the SCC precursory cement - filler paste, the aggregate particle size and the fine particles/coarse particles volumes ratios were the main parameters of SCC mix design. The limestone powder played a beneficial role on the fresh SCC mobility and on the hardening rate in the first 10...48 hrs. The f c2 /f c28 ratio of limestone filler SCC samples was varied from 0.70 to 0.9. The volcanic tuff filler slightly worsened SCC flowability and early strength development. The f c2 /f c28 ratio of volcanic tuff SCC samples was varied from 0.53 to 0.69. On the other hand the volcanic tuff powder has had a better positive influence on the longer term compression strength development than limestone filler.