This paper presents an experimental study on how crumb rubber particles from waste tires and corrugated round steel fibers affect the mechanical behavior of concrete. In addition to the standard plain mix and five combinations of mixes composed of 0.5%, 1.0%, and 1.5% ratios, three steel fiber and crumb rubber mixes, 0.5%, 1.0%, and 2.0% weight of sand, coarse aggregate, cement, and silica fume were evaluated. The percentage of silica fume that replaced the weight of the cement in this study was 8%. The fresh properties of the 12 mixtures in terms of slump and density were studied. After 28 days of curing 36 cubes, 36 cylinders, and 12 prisms, the hardened properties were determined by evaluating the mean compressive, split, and flexural strengths. The results indicate that a synergetic effect is observed for the combination of crumb rubber and corrugated round steel fibers to improve the fresh and hardened properties of concrete. Adding fiber reinforcement to concrete can mitigate the negative impacts of rubber, and vice versa. According to the combination content, increases in compressive strength, tensile strength, and flexural strength of up to 49.04%, 38.60%, and 75.76%, respectively, were achieved compared with the control combination. This validates the applicability of the proposed mathematical prediction formulation to evaluate the compressive strength, split tensile strength, and modulus of rupture of rubberized fibrous concrete in terms of fiber and rubber ratios. Based on these results, a promising solution for tire disposal is to recycle waste rubber for fibrous concrete applications.

Concrete developed from light expanded clay aggregate (LECA) and glass fiber has good performance, durability, and sustainability. Towards this, the experimental investigation was designed to study cubes, cylinders, and simply supported beams. Four mixtures had LECA volume of 0%, 75%, 85%, and 95% as coarse aggregate replacement and glass fiber content volume of 2% (N, L75, L85, and L95), and the other two mixtures had 75% LECA and glass fiber content of 1% and 1.5% (L75-F1 and L75-F1.5). Results compared to normal concrete showed the weight reduction of samples while adding more glass fiber caused slump reduction in contrast to LECA. Increasing glass fiber volume in the mixture had a negative influence on tensile strength while causing compressive strength enhancement. Moment resistance and energy absorption capacity of L85 were enhanced by 7.5% and 10.3%, respectively. For L75-F1 specimens, the beam stiffness and ductility were enhanced by 14.8% and 14.3%, respectively.

Fibers and bacterial additives in concrete have achieved significant success as a construction material. This paper presents the field of concrete self-repairing by introducing both Bacillus subtilis bacteria and polyethylene fiber as a dual-components. The main research goal is to reveal the principles of concrete self-repairing. At first, the research investigates the fiber-reinforced-concrete behavior, the concrete self-repairing process with the Bacillus subtilis bacteria for forming bacterial-concrete. And then, the study highlights the damage-repairing numerical simulation of fiber-reinforced-bacterial-concrete. The research shows the bacterial-concrete benefits to durability and mechanical properties besides to the polyethylene fiber assistance to enhance post-cracking tensile resistance and the pre-peak elastic modulus of concrete. The novelty of the fiber-reinforced-bacterial-concrete is the matrix combined improvement of both basic material properties and the post-cracking deflection capacity.

High-strength concrete incorporating macro-fiber combines high compressive strength of the matrix, strain-hardening, and multiple crack characteristics. Also, calcite sediment remediation bacterial techniques can enhance the mechanical properties, reduce concrete deterioration, and prevent corrosion of steel reinforcement in both the short-term and long-term. In this paper, The Bacillus subtilis bacteria at an optimum dosage of 105 cells/ml of mixing water was incorporated into M60 and M80 concrete strengthened with 0.5% macro synthetic-fiber content. The performance of 32 simply supported reinforced concrete beams with rectangular-section were evaluated numerically using ANSYS. In this study, the properties of matrix components are considered for different geometric sizes as slender and short beams with different longitudinal reinforcement ratios. The results showed that the bacterial participation in fibrous concrete beams had more significant enhancement in the initial cracking load, ultimate load, moment capacity ratio, ductility ratio, and flexural toughness compared to associated conventional concrete.