High performance concretes with silica fume

High performance concretes were studied using 15 % silica fume (a solid waste), 2 - 5 % of a melamine superplasticizer, four types of siliceous gravel, a calcareous aggregate, a siliceous sand, and type I Portland cement. Two maximum size of aggregates were tried: 12.7 mm and 19 mm. The water/cement ratio ranged between 0.28 and 0.31. The highest compressive strength obtained at 56 days of normal curing was 83 MPa. The maximum flexural strength was 10.3 MPa. The average chloride permeability reported 350 coulombs. This result complies the ASTM Standards. The chloride diffusion coefficient was 3.3 x 10(-13) m(2)/s which is low compared with the typical values of normal concretes. From the research results could be concluded the positive effect of the silica fume incorporation in order to obtain high performance concretes.