Portland cement concrete elaborated with by-products of crushing rocks

In the rocks crushing process a particles fraction compound up to 4.75 mm is obtained, which is considered as a by-product called crushed sand. This material is employed in masonry mortars, concrete blocks, and concrete elaboration, and as granular stabilizer of soils for roadbed use. The dust content (material smaller than 75 mu m), of these sands is a point of controversy, on the limits established by the construction bylaws and technological criteria about its effects on both fresh and hardened concrete. The influence of dust in concrete based on two different criteria is evaluated in this work: as partial cement replacement and as constituent of sand. An improvement on the bleeding and degree of cement hidration has been observed.