Método para cuantificar la segregación en hormigones autocompactantes

Abstract

This paper studies the segregation of self-compacting concrete (SCC) with similar rheological characteristics and no signs of segregation in slump-flow test. The characteristics of aggregates influence in the results of segregation tests. When aggregate absorption is high, the penetration tests or visual analysis may not show signs of segregation whereas column method shows clearly the segregation of the mixture (Santos et al., 2012). In this study sands are partially replaced by Granulated Blast Furnace Slag (GBFS). GBFS is higher absorbent than sand or gravel and could modify the paste humidity over time. Seven types of SCC are made, one pattern concrete and the others with different substitutions of fine aggregate by GBFS (10 %, 20 %, 30 %, 40 %, 50 % and 60 %). All of them are made with a w/c ratio of 0. 55 and a cement content of 375 kg/m3 (CEM II / B-M (S-L) 42.5R). A method to quantify the hardened concrete segregation (IEC) is developed and tested, because of slump flow and V-funnel tests are not able to measure the stability of the mixture (Valcuende et al., 2007 y Santos et al., 2012). All SCC mixes showed a good rheological behaviour in fresh state, and none showed segregation signs. The method developed show that IEC index is higher as the aggregate humidity increase