Self-compacting concrete containing silica fume: evaluation of mortar properties

F. SCHIOPETTO; P.M. STEFANI

Congreso; COMAT 2015; 2015

Self-compacting concrete (SCC) is a highly flowable, non-segregating concrete that can spread in to place, fill the formwork and encapsulate the reinforcement without any mechanical vibration for consolidation. SCC has to reach a high segregation resistance and on the other hand a high deformability. The amount of aggregates, additions and mixing water, as well as the type and dosage of superplasticizer to be used are the major factors influencing the fresh state properties of SCC. Assessing the rheological behaviour of mortar is key to achieve the self-compacting condition. In this work, mortars were prepared with a water/(cement + silica fume) ratio of 0.4, varying the silica fume content (0 to 10 wt% of powder), and two different types of sand (siliceous and quartzitic) available in the southeast of Buenos Aires state, Argentina. The bulk densities of siliceous and quartzitic sands were 2.60 and 2.45 g/cm3 and their fineness modulus were 1.39 and 2.88, respectively. Flow and V funnel test were carried out in order to determine the optimum superplasticizer content for each formulation. Compressive strength was evaluated at 28 days. The best combination of properties was reached for the formulation with the highest silica fume content and a siliceous /quartzitic ratio of 60/40