Advances in Science and Technology Vol. 152

Abstract: This study investigated the rheological properties and impact resistance of ultra-high-performance concrete (UHPC) enhanced by using waste steel fibre (WSF) extracted from waste tires. The experimental program involved testing five different percentages of WSF to fortified UHPC, which were produced to illustrate how WSF affected the rheological properties of UHPC. The five different percentages of WSF were of 0.3 %, 0.45%, 0.6%, 1.05% and 1.35% by volume of concrete. Both hardened and fresh properties, such as unit weight, compressive strength, slump, flexural strengths, indirect tensile strength (IDT), and impact resistance of UHPC were analyzed, and the results showed that Compressive strength, IDT, and Flexural increased by 49 %, 79 %, and 40 % for mixtures containing 1.35 % waste steel fibre, respectively. The UHPC mixes also showed significant higher impact resistance compared with conventional mix.

Abstract: The purpose of this paper was to assess the effect of upcycling crushed lightweight bricks and plastic waste on the hardened properties of structural lightweight high-strength concrete before and after exposure to elevated temperatures. The lightweight concrete under study was prepared with sand, lightweight crushed bricks as fine aggregate, dolomite, coarse plastic waste, crushed lightweight bricks as coarse aggregate, Portland cement, silica fume (SF), and high-range water-reducing admixtures (HRWR). Besides the slump test, dry density, compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity were investigated on the produced lightweight concrete. At the age of 28 days, the prepared samples were exposed to high temperatures of 100-800 °C in a preheated test furnace to evaluate the residual mechanical properties of the concrete. The experimental results showed that by increasing the aggregate replacement ratio, the workability slightly increased, and the mechanical properties of lightweight concrete decreased. It is also indicated that crushed lightweight bricks can be recycled as a replacement for natural aggregates to obtain high-strength lightweight concrete with appropriate properties. It has also been proven that crushed lightweight bricks and plastic waste can be used as fine and coarse aggregates to conserve natural resources without significantly deteriorating the properties of concrete. The incorporation of crushed lightweight bricks and coarse plastic waste into high-strength lightweight concrete showed better strength under elevated temperatures.

Abstract: It is crucial to utilize industrial waste and recycled bricks in concrete production, particularly in lightweight concrete, for the sake of sustainability. The objective of this investigation is to produce sustainable, durable, and structural lightweight concrete by replacing natural aggregates (dolomite and sand) with industrial waste (plastic waste) and recycled bricks (crushed lightweight bricks). Two groups of mixtures were conducted in which coarse plastic waste and coarse crushed lightweight bricks were used to partially and fully replace the coarse aggregate in the first group. In the second group, besides replacing the fine aggregate with fine crushed lightweight bricks, the coarse aggregate is also partially and completely replaced, respectively. This experimental work investigated how sustainable lightweight concrete performs in terms of dry density, compressive strength, resistance to chloride penetration, sorptivity, water permeability, and ecological impact. Based on experimental data, replacing aggregate reduced the density of lightweight concrete by up to 1400 kg/m³, lowered its compressive strength by up to 33.8 MPa upon complete replacement of the aggregate, and diminished carbon emissions by up to 2.05%. Compressive strength correlates directly with dry density and inversely with sorptivity and permeability. Investigations have concluded the potential for producing eco-friendly lightweight aggregate concrete suitable for sustainable structural applications.

Abstract: Building Envelope is considered to be the main influencing part of heat transfer into the inner space of the building, as a result the amount of heat transferred into indoors affects the consumption of electrical energy for air conditioning systems. Usually, the Envelope of the building consists of two main components i.e opaque and transparent parts, the opaque part in most buildings consist of bricks, outer and inner plaster layers. This main objective of this research paper is to produce a light weight mortar using plastic bottles waste that is Polyethylene terephthalate (PET) by replacing different proportions of both sand and cement in a separate way, then making an evaluation of physical and mechanical properties of the modified mortar samples. In this paper we have measured coefficient of thermal conductivity, density and compressive strength. The paper shows that an apparent decrease in the values of thermal conductivity coefficient (k) by a percentage of (50%) to (60%) compared to an ordinary mortar.

Abstract: Marble powder (MP) emerges as a byproduct during the cutting and grinding operations of marble stone, constituting a non-biodegradable fine powder. This residue, originating from the marble stone industry, holds the potential for sustainable development when incorporated into self-compacting concrete (SCC). A thorough examination of existing literature underscores the substantial promise of MP as either a supplement or substitute for both cement and fine aggregate in concrete compositions. The literature review provides a comprehensive overview of the incorporation of MP in SCC. An evident trend in the reviewed studies indicates that as the proportion of MP used instead of fine aggregate increases, the fresh properties of the concrete tend to diminish. Nevertheless, the chemical composition of marble, containing CaCO₃ and SiO₂, contributes positively to the mechanical properties of the concrete. Notably, when MP is employed as a replacement for fine aggregate at ratios ranging from 15% to 75%, a discernible enhancement in mechanical properties, ranging from 10% to 30%, is observed. Conversely, substituting MP for cement in quantities exceeding 20% exhibits detrimental effects on both the fresh and mechanical properties of the concrete. The impact of MP on various facets of SCC, including workability, setting times, compressive strength (CS), splitting tensile strength (STS), and flexural strength (FS) has been thoroughly investigated and discussed. This scrutiny contributes valuable insights into the potential advantages and challenges associated with the incorporation of MP in SCC.

Abstract: Supplementary cementitious materials are additives that are used to improve the qualities of Portland cement while also reducing its environmental impact. The production of such blended cements relies on the regional availability of additional components. Despite the prevalence of volcanic tuffs in the Eastern Desert and South Sinai encountered in Egypt, there is a scarcity of knowledge regarding experimental research on cement manufacture. The main objective of this study is to analyze the geochemical and experimental characteristics of several volcanic tuffaceous rocks exploited as natural additional cementitious materials and their impact on the characteristics of the resulting blended cement. The partially replacement can play an important role in reducing the local environmental impacts (CO₂ emissions). Various volcanic rock specimens have been collected from the Sinai (Wadi Kid) and the Eastern Desert (Gabal Umm Zarabit, Wadi Umm Khariga, Gabal Igla El-Iswid, and Abu Wassat), Egypt. The samples under study were examined for their mineralogy, petrography, and chemical composition in order to identify their specifications. In addition, a total of fifteen blended cement samples were produced by partially replacing clinker with the investigated samples. The substitution ratios used were 10%, 20%, and 25% by mass. A control mix was also designed, consisting of ordinary Portland cement without any other substances. An assessment has been conducted on the effects of partially replacing clinker with volcanic rocks on the characteristics of the resulting blended cement. The physico-mechanical parameters, including Blaine, setting time, flexural strength, and compressive strength, of the hardened blended mortars were measured at specific times (7 and 28 days). The study demonstrated that the strength of the studied blended cement mixes decreased as the fraction of the examined volcanic rocks to clinker ratio increased throughout the early stages. The highest compressive strength among the mixtures evaluated was achieved when using a 10% ratio of volcanic rocks as clinker replacement.

Abstract: Traditional solutions for residential buildings often focus on maximizing economic benefit at the expense of environmental and social considerations. As a result, many residential buildings are poorly ventilated, poorly insulated, and lack access to natural light and views. These factors can lead to health problems, discomfort, and energy inefficiency. This research presents an innovative model for environmentally friend housing design that maximize economic value while also considering environmental and social factors. The model is based on an applied case study of a residential development in Cairo, Egypt. The model's key features include orientation of buildings to maximize natural ventilation and daylighting - use of sustainable building materials and construction methods - provision of green spaces and other amenities for residents. The model was able to achieve significant environmental and social benefits, including reduced energy consumption - improved indoor air quality - increased comfort and well-being for residents - enhanced visual and acoustic insulation - the model is also economically viable, providing developers with a competitive advantage in the market. Overall, this research presents a promising new approach to the design of environmentally friendly housing.

Abstract: In recent years, the whole world has been ailed by the change in climate with global warming and its negative effects on Earth’s climate system. Increased emissions and amplified energy consumption have resulted in a remarkable rise across the various climatic regions of Egypt, intensifying the thermal stresses on building facades. So to address this matter through a quantitative study, how climate change influences energy consumption rates will be analysed by referring back to the ECEEE records and Egypt's weather data files. The weather data files follow the seven climate regions and the different cities, starting with Alexandria, then Cairo, Minya, Asyut, Hurghada, Kharga, and finally Aswan. Based on the ECEEE records, each climate region has a particular thermal resistance (R-value) regulated by its zone location and weather conditions, thereby regulating consumption and reducing energy consumption. The simulations will also compare the most recent weather data files for 2021 with the original from 2006 in order to determine whether they are still applicable to today's energy depletion rates. The DesignBuilder program will be used to examine and compare R-values for an air-conditioned office space (6x4) m with a southwest orientation between 2006 and 2021. The results show an increase in Delta and Cairo Regions (2) by 50% , South Upper Egypt Regions (4) by 57% , and East Coast Regions (5) by 43% that were treated with XPS Extruded Polystyrene - CO2 Blowing as an insulation material addition, with its thickness adjusted according to the different regions. Keywords Climate Change, Energy Consumption, R-Value, Energy Code, Climatic Regions, Office Space, Orientation, Software Simulation, Envelope