Effects of fine aggregates types and contents on rheological and fresh properties of SCC

This study presents the effects of different types and proportions of three sands on rheological and hardened properties of self-compacting concrete (SCC). A mixture design approach was used to highlight the effects of river sand (RS), crushed sand (CS) and dune sand (DS) in binary and ternary combinations on flowability, passing ability, static stability, rheological behaviour and compressive strength at 28 days. The obtained mathematical models are very useful to highlight the effects of all possible combinations of RS, CS and DS in ternary contours plots and to optimize the suitable sands combinations for a targeted properties of SCC that require particular guidelines. Results indicate that for a given sands combination, flowability requirements can be achieved (Slump flow from 65 to 79 cm, T50 time between 2 and 5 s and V-funnel time greater than 6 s), despite the negative effects of high proportions of DS and CS on passing ability expressed by L-box test (H2/H1 less than 0.8). However, attention should best be focused on passing ability and static stability requirements, which are considerably affected by high DS and CS proportions (maximum Pi value of 15% and Pd value of 10 mm). Good relationships between SCC mortar rheology parameters measured with the use of a rheometer (yield stress and plastic viscosity issued from modified Bingham model) and fresh properties of SCC were obtained (Yield stress with L-Box ratio and Pi, plastic viscosity with V-funnel and Pd) with respect to the effects of type and content of used sands.