Civil Sustain. Urban Eng. 98 views
Abstract The beam is a structural element in a reinforced concrete structure. However, its weight places additional strain on the columns and foundations.Polystyrene spheres can be used to replace concrete in a beam to reduce its weight. However, this can affect the beam’s structural performance. This study investigated the behavior of beams with embedded polystyrene spheres under loads. The purpose was to determine the feasibility of this technique. Six beam specimens, including a control specimen, were tested under the four-point load setup. The polystyrene spheres’ diameter ranged from 50 mm to 75 mm. The spacing between the spheres varied from 10 mm to 30 mm. By replacing 8.7% of the concrete, the beam's strength increased by 8% per unit of concrete. The polystyrene spheres marginally altered the load capacity but reduced the stiffness, uncracked load, and ductility. The load capacity decreased by 2.6% as the polystyrene sphere’s diameter increased from 50 mm to 10 mm. The strength increased by 0.6% as the spacing increased from 10 mm to 30 mm. For satisfactory performance, the polystyrene spheres with a diameter of 0.57 times the beam’s width may be spaced at 1.2 times the concrete cover.[...] Read more. Full text

Civil Sustain. Urban Eng. 88 views
Abstract Geopolymers, primarily composed of fly ash, have proved an excellent substitute for ordinary portland cement (OPC) in terms of sustainability and productivity. In order to determine the geopolymer concrete's (GPC) resistance to chemical assaults and water permeability, it is necessary to obtain geopolymer concrete (GPC) of varying strengths after normal curing. The objectives of the research was to test the durability performances of the GPC of various strength under normal curing and investigating the optimum strength based on durability testing of the GPC. For this research, different type of cement-to-fly ash ratio was used for various strength data. The appropriate mixture was conducted by using the trial mix method in order to obtain better accuracy of the results data during the mixing design process. To satisfy the varied strength designs, a small proportion of OPC is added to the GPC mixture as part of the mix design. After 28 days of curing, this durability testing is undertaken after the concrete has reached its maximum strength. The compressive strength test and weights were performed and compared to the GPC mix design at 60 °C after heat curing. The 8% OPC replacement has greater resistance to sulfate attack, saltwater exposure, and water permeability compared to the 6% and 7% OPC alternatives. Consequently, the experiment reveals that the GPC's durability and strength increase as the percentage of OPC increases.[...] Read more. Full text

Civil Sustain. Urban Eng. 198 views
Abstract The issue of the cathode ray tube (CRT) technology facing its end-of-time and increasing quantities across the globe has acquired the responsiveness of many researchers. The use of waste CRT glass as a construction material has fascinated them due to its significant advantage in recycling the hazardous and non-biodegradable waste CRT glass. However, lack of knowledge about the effects and features of CRT glass as a construction material could be a hindrance to the excessive utilization of waste CRT glass. Therefore, in order to establish the idea of using CRT waste glass as a more common construction material, this paper reviews several recycling techniques of CRT glass and further detail on the workability, density, and compressive strength properties of concrete and mortar using CRT glass (treated or untreated) as fine aggregates. The review showed that, generally, the use of CRT glass as a complete or partial replacement of natural sand shows a slight increase in density, workability, and concrete strength compared to conventional concrete. However, there are no clear trends that can be concluded as this review also showed that various factors influenced its performance, such as percentage replacement, particle size, lead (Pb) content, and types of admixtures.[...] Read more. Full text