In this investigation distinctive self-compacting concretes (SCC) containing both marble + granite (MG) powder and hooked-end steel fibers (HESF) are investigated. A mixture of conventional SCC (reference), and other five samples containing MG and steel fiber (SF) contents are provided, i.e. 20MG, 20SF, 30MG + 10SF, 20SF and 30MG + 20 SF. Both the fresh and hardened properties of the modified self-compacting concretes are evaluated. Workability of the SCC samples represented by slump flow, L-box, V-funnel, J-ring and flowability T500 is examined. The properties of hardened state of the SCC samples at 7 and 28 days are also evaluated. Modulus of elasticity, water absortion, voids index (indicatig porosity), and specific mass are attained. Comparisons among specific strengths and consumptions of cement per compressive strengths are also provided. The SCC/30MG/10SF sample has a specific strength ∼50% higher than the conventional SCC sample. When a ratio involving porosity per cement consumption per tensile strength is evaluated, the SCC/30MG/10SF sample has this ratio ∼80% higher than the SCC reference. Additionally, the best result of consumption of cement (CC) per compressive strength (CS) (1.28x lower than the SCC reference) at 28 days is that of the SCC/30MG/10SF sample (5.03 kg/m3. MPa−1). This indicates that an environmentally friendly aspect associated with low relative cost, which is an important parameter to consider in future SCC mixture designing.

The advances in concrete technology lead to the search for alternative materials that provide improvements in concrete properties while at the same time collaborating with sustainable practices in construction. In this study, the influence of the incorporation of waste tire rubber on the mechanical properties of high-performance concrete was discussed. The waste rubber from the tire retreading process was used in partial substitution of the fine aggregate (sand) in the percentages of 7.5%, 15% and 30% with respect to the mass of the sand. For the characterization of the concrete, the following tests were carried out: water absorption, void index, specific density, compressive strength, flexural tensile strength, modulus of elasticity and microscopy analysis. The incorporation of rubber as aggregate in high-performance concrete proved to be promising for the production of a structural concrete with special characteristics, besides collaborating with the proper disposal of waste tires.

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