Construction Technologies and Architecture Vol. 20

Abstract: This research investigated the mechanical properties, impact resistance, and behavior under elevated temperatures of Fiber Rubberized High-Strength Concrete (FRHSC), which incorporates Waste Steel Fiber (WSF) and Crumbed Rubber (CR) obtained from waste tires. The study involved five different concrete mixtures to explore the impact of WSF and CR. WSF was consistently mixed in a ratio of 0.3% by volume of the concrete. CR was used to partially replace the fine aggregate in proportions of 10%, 20%, 30%, and 40% by volume. The study examined various characteristics of both the fresh and hardened FRHSC, including slump, unit weight, compressive, tensile, and flexural strengths, as well as its impact resistance. The effects of elevated temperatures at ambient, 200 °C, 400 °C, and 600 °C for a period of 2 hours were also analyzed, focusing on the failure shape, and residual compressive strength. Findings indicated that as the quantity of rubber in the concrete samples increased, there was a noted gradual decline in their mechanical properties. Concurrently, this increase in rubber content contributed to an enhancement in the ductility of the samples. The energy absorption by the rubberized specimens was found to be consistent, regardless of the variation in rubber content due to the presence of WSF. The residual compressive strengths of FRHSC subjected to elevated temperatures improved with the addition of CR. The presence of CR led to an increase in the concrete's porosity, and exposure to high temperatures resulted in more cracks due to CR evaporation and the replacement of air voids, causing a notable reduction in compressive strengths. Keywords Fiber reinforced Concrete; Crumb rubber; waste steel fiber; waste tires, Rubberized concrete; Impact energy; Mechanical properties; Elevated temperature.

Abstract: Fire hazards in buildings pose a critical challenge, necessitating effective fire protection measures. This study evaluates the potential of nano-calcium hydroxide (NCH) as an additive in fire-resistant paints. Laboratory experiments were conducted following the ASTM E119 standard, testing paint formulations with 1% and 3% NCH. Thermal resistance, protective performance, and economic feasibility were analyzed. Results indicate that NCH-modified paints significantly enhance fire resistance compared to conventional coatings, offering a promising solution for improved fire protection in construction.

Abstract: The construction industry is a complex business. Due to it consists of a various types of stakeholders characterized with different objectives, skills, cultures and professions. This requires effective communication management between the different stakeholders to facilitate their interaction and ensure the delivery of successful projects. Communication is a process that involves the transfer of information between parties and it is directly affects the project’s success. Poor communication can result in project failure especially in severe cases where the problem is left unsolved. The main objective of this study is to determine the causes and impacts of poor communication in residential projects. Data from 21 recent residential projects were collected to determine causes and impacts of poor communication in residential projects. The results showed that the most significant causes and impacts of poor communication in residential projects. Egyptian construction parties can use these results to enhance communication in residential projects.

Abstract: Reverse osmosis (RO), the main technique for desalination, is affected by the quality of the water source. Natural water contains silica, which comes from metal silicates found in the earth's crust. Silica fouling is complicated to manage and often leads to less efficient designs of RO systems for safe operation. This research evaluates the current technologies for treating silica in RO desalination. The pilot project showed considerable water savings, achieving maximum recovery over the longest duration. To enhance water conservation, it is essential to optimize permeate recovery. Water savings were constrained due to silica scaling on the membranes. The chosen membranes can achieve a lower total dissolved solids (TDS) rejection than was required in the initial research, which could enhance water conservation. The additional energy needed for membrane treatment was balanced out by the savings in water costs. To avoid scaling, an antiscalant chemical along with a dosing system was installed next to the membrane system, and this study focused on three methods to mitigate silica scaling: Amonium Bifloride (ABF), a cation ion exchange column (IEX) containing Amberlite-IRC747 (Dupont) resins to eliminate multivalent cations like Ca2+, Mg2+, and Fe3+. Lastly, a simulated anti-scaling test was conducted using a feed solution that was pretreated by MIL-101(Fe) adsorption. Each type of antiscalant suitable for decreasing silica from water possesses distinct characteristics such as pH and other cations. Keywords:, Water conservation, Silica , Anti-Scalant, Amonium Bifloride (ABF), Exchange column (IEX) filled with Amberlite-IRC747 (Dupont), MIL-101(Fe).

Abstract: The use of aluminum oxide nanoparticles (Al-NPs) in wastewater treatment has emerged as a promising approach due to their unique physicochemical properties, including a high surface area, strong adsorption capabilities, and effective adsorbent performance. This study investigates the use of Al-NPs for the removal of chemical oxygen demand (COD) from synthetic aqueous solutions. COD is one of the main indicators of water pollution and can be used to assess water quality. The characterization of Al-NPs was conducted using various techniques, including X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), and the Brunauer-Emmett-Teller (BET) technique. XRD analysis confirmed the successful synthesis of Al-NPs with a well-defined crystalline structure and desirable crystallite size. The data correlated with TEM findings, validating the nanoscale properties of the Al-NPs. The EDX spectrum showed prominent peaks corresponding to aluminum (Al) and oxygen (O), indicating the presence of Al and possibly Al₂O₃. A higher BET surface area typically correlates with improved pollutant adsorption performance, as more surface sites are available for interaction. Adsorption data were analyzed using the Freundlich isotherm model, which suggested a heterogeneous adsorption surface, and the pseudo-second-order kinetic model, indicating that the adsorption mechanism was predominantly chemisorption. These findings highlight the potential of Al-NPs as effective adsorbents for pollutant removal from wastewater, with implications for optimizing treatment processes in industrial and domestic applications. The maximum removal efficiencies (R%) for chemical oxygen demand (COD), phosphate (PO₄), and total suspended solids (TSS) were 97.04%, 42.62%, and 98.63%, respectively. The highest removal efficiency was achieved at an Al-NP dosage of 120 mg/L. These findings demonstrate that Al-NPs can be effectively used as coagulants in wastewater treatment.