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The sustainable utility of industrial waste and by‐products is crucial to reduce environmental impact. Particularly relevant for the cement and concrete industry, where recycling and utilization of industrial waste can help to replace normal concrete and promote stable growth. One such waste material is aluminum computer numerical control waste (ALCNCW). This study investigated the performance of reinforced concrete beams incorporated with ALCNCW. It was decided to use the effects of the ALCNCW ratio and the proportion of longitudinal reinforcement as parameters. A total of 12 reinforced concrete beams were cast and tested with varying levels of lower reinforcement ratios (0.0125, 0.0074, and 0.0032) and ALCNCW ratios (1%, 2%, and 3% by weight), in addition to a control beam. The load‐carrying capacity, failure mode, crack patterns, ductility, and serviceability were analyzed. The findings of the experiments demonstrated that the cracking and bending effects of reinforced concrete beams were different depending on the quantity of tension reinforcement and ALCNCW that was used. The results indicate that adding 1% or 2% of ALCNCW to concrete beams has a negligible effect on the load capacity. However, the ductility of the beams was adversely affected. Nevertheless, adding ALCNCW to the concrete mix can still be implemented with a specific ratio. Finally, all 12 beams met the serviceability limit state requirements. [ABSTRACT FROM AUTHOR]

The study conducted axial tensile strength tests on concrete samples that replaced conventional aggregates with recycled aggregates. In Series I, using FNG instead of FNA resulted in a reduction in compressive strength by 12.8–49.8% and tensile strength by 14.5–44.6%. If the proportion of FNG exceeds 50%, compressive strength decreases by more than 24.5% and tensile strength by more than 27.5%. In Series II, replacing CNA with CRG reduced compressive and tensile strengths by 18.4–32.8% and 5.1–24.9%, respectively; exceeding 40% CRG results in a compressive strength reduction of more than 32.8% and a tensile strength reduction of more than 24.9%. In Series III, samples made with RCA, CNA, and 20% CRG showed a compressive strength decrease of 8.8–22% and a tensile strength decrease of 10.7–26%; RCA80 samples showed maximum reductions. In Series IV, replacing CNA with RCA resulted in compressive and tensile strength reductions of 15.4–34.7% and 13.9–24.3%, respectively; RCA80 samples again showed maximum reductions. Maximum stress unit deformation values (εo) increased by 3–58.4% in Series I, 9–80% in Series II, 10–44.9% in Series III, and 9–32% in Series IV. Tensile toughness values showed the highest increase of 35.15% in the CRG40 sample and the lowest of 0.13% in the RCA40-20 sample. The use of glass aggregates in concrete is feasible, but exceeding certain ratios can significantly reduce strength. Concrete can effectively use waste glass as a partial substitute for cement, fine aggregates, or as a filler material, potentially enhancing compressive strength. [ABSTRACT FROM AUTHOR]

The recycling of the aquaculture waste into clam powder reduces solid emissions and natural resources, which is important for Portland cement production. This study determines the feasibility of using recycled river shell waste as a partial replacement for cement in concrete technology. The study used normative methods and optical microscopy; the properties of cement mixtures, such as normal consistency, setting time (ST), compressive and flexural strength, were studied. Research findings have shown that the inclusion of river shell powder (RSP) in cement mixtures can reduce water demand and a decrease in setting time with increasing RSP content. It was also found that the strength of the cement mixture can be maintained with an RSP content of up to 10%. The following properties of the concrete were determined: workability, compressive strength (CS), and water absorption. Using RSP as a partial replacement for cement has been proven to elevate the slump of the fresh concrete cone. CS is maintained at a level comparable to the control composition, with an RSP content of no more than 8%, and water-absorbing is reduced by 7.31%. This study created new compositions, and the links between the ingredients, properties, and structure of cement composites modified with river shell powder were investigated. Additionally, the properties of the structure-formation process of these modified composites were studied. [ABSTRACT FROM AUTHOR]

Industrial waste usage in the technology of construction materials is currently in a relevant and promising direction. Materials made of industrial waste have a lower cost and are highly environmentally friendly. The objective of this study is to develop effective compositions of sulfur concrete based on the maximum possible number of various wastes of the local industry for this and to investigate the characteristics of this composite. Test samples of sulfur concrete were made from sulfur, fly ash, mineral aggregates and bitumen additive. The dosages of fly ash, sand and bitumen varied, while the content of sulfur and crushed stone remained constant. The following main characteristics of sulfur concrete were determined: density; compressive strength; and water absorption. Tests of sulfur concrete were carried out after 1 day and 28 days of hardening. The best values of compressive strength (24.8 MPa) and water absorption (0.9%) were recorded for the composition of sulfur concrete at the age of 28 days with the following content of components: sulfur—25%, modified with 4% bitumen of its mass; fly ash—10%; crushed stone—40%; and sand—25%. The optimal composition of modified sulfur concrete showed compressive strength up to 78% more and water absorption up to 53% less than the control composition. The characteristics of the sulfur concrete samples after 28 days of hardening differ slightly from the values after 1 day of hardening (up to 1.8%). An analysis of the structure confirmed the effectiveness of the developed composition of sulfur concrete in comparison with the control. [ABSTRACT FROM AUTHOR]

The use of vibro-centrifugation technology allows the manufacture of variotropic structures that are inhomogeneous in the annular section and have different characteristics along the section thickness. Hardening of the outer layers allows the structure to better resist bending conditions, however, the behavior of the variotropic column under central and eccentric compression remains unexplored. This article considers the problem of compression of hollow columns made of homogeneous concrete that is non-uniform in the annular section (variotropic), and is reinforced with steel reinforcing bars at different values of the load application eccentricity. Variotropic concrete obtained by vibro-centrifugation technology has a stronger outer part and a less durable inner part. The strength of a homogeneous column corresponds to the strength of the middle part of variotropic concrete. The problem was solved numerically in the ANSYS environment for a vertical column rigidly clamped at the bottom edge and loaded with eccentricity at the top edge. Three types of eccentricity are considered; e/r = 0, 0.16 and 0.32 (respectively 0 mm, 0.24 mm and 48 mm). The results of the solution in the form of stress fields, deformations and a pattern of crack development in a spatial setting are obtained. The results showed that for central compression, a homogeneous column has a better bearing capacity of 3.6% than a variotropic one. With the values of eccentricity e/r = 0.16 and 0.32, the variotropic column has a higher bearing capacity (by 5.5% and 6.2%) than the homogeneous one and better resists the development of cracks. The significance of the study lies in the practical application of the proposed approach, developed on a research basis, for non-trivial and complicated operating conditions of columns. This study influences the development of reinforced concrete structures and applies scientific findings to engineering practice. [ABSTRACT FROM AUTHOR]