Incorporating various industrial waste materials into concrete has recently gained attention for sustainable construction. This paper, for the first time, studies the effects of silica stone waste (SSW) powder on concrete. The cement of concrete was replaced with 5, 10, 15, and 20% of the SSW powder. The mechanical properties of concrete, such as compressive and tensile strength, were studied. Furthermore, the microstructure of concrete was studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy analysis (EDX), Fourier transformed infrared spectroscopy (FTIR), and X-Ray diffraction (XRD) tests. Compressive and tensile strength of samples with 5% SSW powder was improved up to 18.8% and 10.46%, respectively. As can be observed in the SEM images, a reduced number of pores and higher density in the matrix can explain the better compressive strength of samples with 5% SSW powder.

Crack propagation can be affected by the holes of the placement of rebars in the reinforced concrete and the resulting changes in the homogeneous structure of concrete. This experimental study aimed at investigating the fiber self-compacting concrete failure and crack propagation in concrete specimens with circular central holes and contain 2, 4, and 8 fiber percentages. The crack propagation mechanisms under the uniaxial compressive strength of the concrete were studied by investigating the holes created by rebars buried in the reinforced concrete. Three concrete mix designs with different compressive strengths of 27, 30, and 33 MPa were used for detailed analysis of the fiber concrete behavior by 224 standard 150 mm cubic specimens. The results showed the insignificant impact of small holes with an approximate area of 1.4% of the specimen surface area on the failure structure so that crack propagation in this case was similar to that occurred in the hole-free concrete. The compressive strength of concrete decreased, by increasing the crack prorogation around the holes. The compressive strength of the concrete may be reduced significantly by increasing the hole diameter. Taking into account these factors in the design of the connection core can reduce the compressive strength of concrete by 30% depending on the rebar grid.