Properties of a Low-Carbon Binder-Based Mortar Made with Waste LCD Glass and Waste Rope (Nylon) Fibers

Carbon dioxide emissions are one of the problems that arouses the interest of scientists because of their harmful effects on the environment and climate. The construction sector, particularly the cement industry, is a significant source of CO2. On the other hand, solid waste constitutes a major problem facing governments due to the difficulty of decomposing it and the fact that it requires large areas for landfill. Among these wastes are LCD waste glass (WG) and used rope waste. Therefore, reusing these wastes, for example, in concrete technology, is a promising solution to reduce their environmental impact. Limited studies have dealt with the simultaneous utilization of glass waste as a substitute for cement and rope waste (nylon) fiber (WRF). Therefore, this study aimed to partially replace cement with WG with the addition of rope waste as fibers. Thirteen mixtures were poured: a reference mixture (without replacement or addition) and three other groups containing WG and WRF in proportions of 5, 15 and 25% by cement weight and 0.25, 0.5 and 0.75% by mortar weight, respectively. Flow rate, compression strength, flexural strength, dry density, water absorption, dynamic modulus of elasticity, ultrasonic pulse velocity and electrical resistivity were tested. The results indicate that the best ratio for replacing cement with WG without fibers was 5% of the weight of cement. However, using WRF increased the amount of glass replacement to 25%, with an improvement in strength and durability characteristics

Potential Use of Rendering Mortar Waste Powder as a Cement Replacement Material: Fresh, Mechanical, Durability and Microstructural Properties

The difficulty of decomposing solid waste over time has made it a significant global problem because of its environmental impact and the need for large areas for disposal. Among these residues is the waste of the rendering mortar that is produced (falls to the ground) while applied to wall surfaces. The quantity of these materials may reach 200 to 500 g/m2. As a result of local urban development (in Iraq), thousands of tons of these wastes are produced annually. On the other hand, the emission of greenhouse gases in the cement industry has had a great environmental impact. One of the solutions to this problem is to reduce the cement content in the mix by replacing it with less emissive materials. Residues from other industries are considered a relatively ideal option due to their disposal on the one hand and the reduction of harmful emissions of the cement industry on the other hand. Therefore, this research aims to reuse rendering mortar waste powder (RMWP) as a possible alternative to cement in mortar. RMWP replaced the cement in proportions (0, 10, 15, 20, 25, and 30% by weight). The flow rate, flexural and compressive strengths, ultrasonic pulse velocity, bulk density, dynamic modulus of elasticity, electrical resistivity, and water absorption tests of the produced mortar were executed. Microstructural analysis of the produced mortar was also investigated. Results indicated that, for sustainable development, an eco-friendly mortar can be made by replacing cement with RMWP at a rate of 15%, resulting in a 17% decrease in compressive strength while maintaining or improving durability properties. Moreover, the microstructure became denser and more homogeneous in the presence of RMWP

Performance Comparison of 45° and 90° Herringboned Permeable Interlocking Concrete Pavement

Pavement deterioration is mainly caused by high traffic loading and by increased levels of runoff water resulting from storms, floods, or other reasons. Consequently, this issue can be efficiently solved by employing permeable pavement, such as permeable interlocking concrete pavement (PICP) to control water runoff and endure increased traffic loads. This study investigates the performance of PICP, in both 45° and 90° herringboned surface patterns, in terms of the infiltration of volumes of water, runoff water volumes, and the ability of pavement to withstand static loading. All the related tests in this study were implemented using a lab apparatus that was fabricated as a simulator for rainfall. Various conditions were adopted during the performance tests, including the application of longitudinal slopes (0, 2.5, 5, and 7.5%), side slopes (0, 2.5, and 5%), and different rainfall intensities (25, 50, 75, and 100 L/min). The results indicated that at high rainfall intensities (75 and 100 L/min), PICP with the 45° herringboned surface pattern had the highest volume of infiltrated water and the lowest runoff water at all the adopted longitudinal and side slopes. In addition, PICP with the 45° herringboned surface pattern showed higher resistance to deflection under a static loading test than the 90° herringboned pattern under the same conditions. Therefore, PICP with a 45° herringboned surface pattern showed supremacy in terms of runoff reduction and load resistance in comparison to PICP with a 90° herringboned pattern. Even though there are differences between the two types of PICP, they are both strongly recommended as alternatives to regular pavement

The effect of industrial and waste fibres on concrete strength and structural behaviour of rc short columns

Concrete is a brittle substance; thus, it is reinforced with rebars and fibers to enhance its ductility. On the other hand, the presence of waste from various industries negatively impacts the environment. The ongoing reconstruction in Iraq has resulted in an abundance of locally produced rebar-connecting wire (RCW) and copper electric wire (CEW) waste. To minimize the environmental impact of these wastes, they can be reused in other industries, such as the concrete industry. Few studies have dealt with concrete's structural and mechanical properties containing these local residues. Therefore, this study included an experimental investigation of concrete columns with and without various types of industrial and waste fibers. Two types of industrial fibers (macro hooked-end; CH, and micro straight; CS) steel fibers and two types of waste fibers (RCW and CEW) were utilized. Six reinforced concrete (RC) columns (150 × 150 × 450 mm3) were cast: one control column without fibers and five columns with fibers. The fiber content within the columns was fixed at 0.75% of the concrete volume. The cracks pattern, load-deflection behavior and concrete strain for RC columns were investigated. Moreover, the mechanical properties in terms of compressive, splitting tensile, and flexural strengths tests were also conducted. The results revealed that all types of fibers used improved the mechanical and structural properties of the concrete. Moreover, although the hybrid synthetic fibers gave the best improvement compared to the reference sample, the waste fibers (especially RCW) showed a significant improvement that reached 30.91% in relation to the ultimate load and (10.1, 10.8 and 14.4%) in relation to the compressive, tensile, and flexural strengths respectively. Konkrit adalah material rapuh; oleh itu ianya dikuatkan dengan besi dan fiber bagi menguatkan kekuatannya. Dalam masa sama, kehadiran bahan buangan dalam pelbagai industri memberi kesan negatif kepada persekitaran. Penstrukturan semula Iraq yang sedang berlangsung memberi kesan kepada kebanjiran bahan buangan seperti besi penghubung litar (RCW) dan litar elektrik tembaga (CEW) buatan tempatan. Bagi mengurangkan kesan pencemaran terhadap alam sekitar, bahan-bahan ini boleh diguna balik dalam industri berbeza, seperti industri konkrit. Terdapat banyak kajian terhadap buangan tempatan yang melibatkan struktur bahan konkrit dan sifat mekanikal.  Oleh itu, kajian ini merupakan kajian eksperimen pasak konkrit dengan atau tanpa pelbagai jenis industri dan fiber buangan. Dua jenis fiber industri iaitu fiber besi (mikro hujung-penyangkut; CH dan mikro lurus; CS) dan dua jenis fiber buangan (RCW dan CEW) dipakai. Enam RC pasak konkrit (150 × 150 × 450 mm3) dihasilkan: satu pasak kawalan tanpa fiber dan lima pasak dengan fiber. Kandungan fiber dalam pasak di tetapkan pada 0.75% isipadu konkrit. Corak rekahan, ciri-ciri kesan beban dan tekanan konkrit pada pasak RC dikaji. Tambahan, kajian terhadap ciri-ciri mekanikal berdasarkan tekanan, rekahan tensil dan kekuatan anjalan telah dijalankan. Dapatan kajian menunjukkan kesemua fiber yang digunakan menambah baik ciri-ciri mekanikal dan struktur konkrit. Tambahan lagi, walaupun fiber sintetik hibrid menunjukkan paling baik berbanding sampel contoh, fiber buangan (terutama RCW) menunjukkan pembaharuan ketara mencapai 30.91% berbanding beban maksimum dan masing-masing menunjukkan 10.1, 10.8 dan 14.4% pada tekanan, rekahan tensil dan kekuatan anjalan

Properties of Modified Warm-Mix Asphalt Mixtures Containing Different Percentages of Reclaimed Asphalt Pavement

The Rapid reduction of energy resources and the escalated effects of global warming have created a strong motivation to find some new techniques in the field of paving construction. Adopting new technologies, such as warm-mix asphalt (WMA) or the recycling process of asphalt can be very helpful for the economy and have a significant impact on the environmental footprint. Thus, this research aimed to study the mechanical and durable characteristics of modified WMA mixtures using (1.0%, 1.5%, and 2.0%) Sasobit REDUX®, (0.3%, 0.4%, and 0.5%) Aspha-Min®, and (0.07%, 0.1%, and 0.125) ZycoTherm® additives corresponding to three percentages of reclaimed asphalt pavement (RAP) (20%, 40%, and 60%). Three mixing temperatures have been conducted in this study to generate WMA mixtures at (135 °C, 125 °C, and 115 °C) corresponding to three compacting temperatures (125 °C, 115 °C, and 105 °C). The mechanical properties of the developed WMA mixtures have been evaluated using the Superpave volumetric properties (air voids, voids filled with asphalt, and voids in mineral aggregate), while the durable properties have been investigated using the resilient modulus test (MR) at 25 °C, resilient modulus ratio (RMR), and Hamburg wheel-track test in terms of permanent deformation, moisture susceptibility, and rutting resistance. To make the WMA mixtures accept high quantities of RAP (>25%), an insignificant increase in the amounts of WMA additives was needed to produce mixtures carrying sustainability labels. Results indicated that all the used additives had pushed the WMA mixtures to achieve considerable mechanical properties, whereas the best properties for the WMA mixtures containing 0%, 20%, 40%, and 60% of RAP have been achieved by mixing with (1.0% Sasobit REDUX® @ 125 °C), (1.0% Sasobit REDUX® or 0.3% Aspha-Min® @ 135 °C), (1.5% Sasobit REDUX® @ 125 °C), and (2.0% Sasobit REDUX® or 0.5% Aspha-Min® @ 135 °C), respectively. On another hand, the best durable properties have been achieved by mixing the mentioned WMA mixtures containing 0%, 20%, 40%, and 60% of RAP with 0.07%, 0.07%, 0.1%, and 0.125% of ZycoTherm® at 153 °C, respectively. Using such additives in the recycled WMA mixtures made it possible to activate waste recycling in the paving industry

Effect of Clay Brick Waste Powder on the Fresh and Hardened Properties of Self-Compacting Concrete: State-of-the-Art and Life Cycle Assessment

Sustainability and reducing environmental damage caused by CO2 emissions have become issues of interest to researchers in the construction sector around the world. Reducing the cement content in concrete by partially substituting it with by-products or waste falls within this field as the cement industry is responsible for 7% of global CO2 emissions. On the other hand, self-compacting concrete (SCC) is one of the special types of concrete that contains a large amount of powder (most of which is cement) to ensure its flow under the influence of its weight without separating its components. Therefore, to produce eco-friendly SCC, many researchers have replaced part of the cement with clay brick waste powder (CBWP) since brick units are among the most widely used building materials after concrete. Accordingly, this study aims to review previous research that included using CBWP in SCC. The effect of these wastes on the fresh, mechanical, durability and microstructural properties of cement was reviewed. Additionally, a comparison between the environmental impacts of SCCs with different CBWP contents has been conducted using the life cycle assessment (LCA) approach. It was found that the highest value of CBWP that can be used without negatively affecting the different properties of concrete is 10% by weight of cement. Moreover, regarding environmental impact, using CBWP as a substitute for cement reduces environmental damage, and the lowest environmental impact that can be achieved per strength unit (MPa) is 37.5%

Studying the effect of shear stud distribution on the behavior of steel-reactive powder concrete composite beams using ABAQUS software

Using the ABAQUS software, this article presents a numerical investigation on the effects of various stud distributions on the behavior of composite beams. A total of 24 continuous 2-span composite beam samples with a span length of 1 m were examined (concrete slab at the top and steel I-section at the bottom). The concrete slab used is made of a reactive powder concrete with a compressive strength of 100.29 MPa. The total depth of each sample was 0.220 m. The samples were separated into four groups. The first group involved 6 specimens with shear connectors distributed into 2 rows with different distances (65, 85, 105, 150, 200, and 250 mm). The second group had the same spacing of shear connectors as the first group except that the shear connectors were distributed with one row along the longitudinal axis. The third group consisted of six specimens with single and double shear connectors distributed along the longitudinal axis. The fourth group included six specimens with one row of shear connectors arranged in a staggered distribution along the longitudinal axis. Results show that the optimum spacing was 105 mm in all groups and the deflection in group four fluctuated up and down due to the non-symmetrical distribution of the shear connectors

Violent Deaths of Iraqi Civilians, 2003–2008: Analysis by Perpetrator, Weapon, Time, and Location

Madelyn Hsiao-Rei Hicks and colleagues provide a detailed analysis of Iraqi civilian violent deaths during 2003-2008 of the Iraq war and show that of 92,614 deaths, unknown perpetrators caused 74% of deaths, Coalition forces 12%, and Anti-Coalition forces 11%

An overview of the utilisation of microalgae biomass derived from nutrient recycling of wet market wastewater and slaughterhouse wastewater

Microalgae have high nutritional values for aquatic organisms compared to fish meal, because microalgae cells are rich in proteins, lipids, and carbohydrates. However, the high cost for the commercial production of microalgae biomass using fresh water or artificial media limits its use as fish feed. Few studies have investigated the potential of wet market wastewater and slaughterhouse wastewater for the production of microalgae biomass. Hence, this study aims to highlight the potential of these types of wastewater as an alternative superior medium for microalgae biomass as they contain high levels of nutrients required for microalgae growth. This paper focuses on the benefits of microalgae biomass produced during the phycore-mediation of wet market wastewater and slaughterhouse wastewater as fish feed. The extraction techniques for lipids and proteins as well as the studies conducted on the use of microalgae biomass as fish feed were reviewed. The results showed that microalgae biomass can be used as fish feed due to feed utilisation efficiency, physiological activity, increased resistance for several diseases, improved stress response, and improved protein retention