The effect of blending granular aggregates of different origin on the strength of concrete

• Published in: Physica A Vol. 391; no. 5; pp. 1934 - 1941
• Main Authors: Médici, M.E., Benegas, O.A., Uñac, R.O., Vidales, A.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2012
• Subjects: Aggregates; Concrete; Concretes; Crushing; Density; Grains; Granular aggregates; Origins; Packing density; Physical properties; Specific surface; Packing density; Granular aggregates; Concrete
• ISSN: 0378-4371; 1873-2119
• DOI: 10.1016/j.physa.2011.10.034

This work correlates the resistance of concrete cores with the physical properties of the granular material forming it. A basic physical characterization is conducted, taking into account the origin of the grains involved in the concrete mixture; that is, if they come from natural degradation (natural granular aggregates) or from a grinding process (crushed granular aggregates). Apparent and real densities, shape factors, packing densities, and specific surface areas of the grains are measured. The results are discussed as a function of size and origin of the grains. Several mixtures are prepared following a standard protocol and using different ratios of natural and crushed aggregates. For each ratio, six cores are prepared and uniaxial compression tests are performed. A non-monotonic relation between the resistance of concrete and the percentage of crushed aggregate present in it is obtained, with an optimum ratio depending on the physical properties of the grains. ► We present experimental results on granular systems. ► We give a physical characterization of grains used in concrete production. ► We determine the packing density and specific surface area for different mixtures of grains. ► We study the behavior of the strength of concrete cores as a function of the grain mixtures. ► We present a description of the two competing effects intervening in the strength response.