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Environmental pollution due to CO 2 emissions from the cement industry and the depletion of the natural resources of the aggregate used in the concrete industry call for the need to find alternatives to reduce these harmful effects. Some of these alternatives include the use of supplementary cementitious materials and the reuse of wastes from other...
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Context 1
... Table 1) is identical to Iraqi Standard No. 5 / 1984 [18]. The specific gravity of this cement is 3.1 and the fineness (which is measured using Bettersize2000 laser particle size analyzer device) is 291 m 2 /Kg. The particle size distribution of cement is presented in Fig. 1. Scanning electron microscope (SEM) image of cement is illustrated in Fig. ...
Context 2
... 0.075 mm sieve opening was used as a partial replacement of cement [21] while the powder with a size range of(0.15-0.075 mm) was used as a substitute for natural sand. The specific gravity of CCP is 2.19. The fineness of CCP is 334 m 2 /Kg. The particle size distribution of CCP is shown in Fig. 1 while its morphology (using SEM) can be seen in Fig. ...
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Pervious concrete paving blocks (PCPB) is a material that widely used for the surface layer of road either for traffic or non-traffic needs. The main characteristic is the pores within the concrete which can allow water to pass through so it can prevent inundation when rain comes. Good absorption rate is not in line with its compressive strength. I...
Considering the advantages of energy conservation and reducing the construction skill requirement of the workers, a new type of interlocking hollow block using recycled aggregates concrete (IHB-RAC) with the compressive strength up to 10 Mpa was proposed, which could help improve more than 56% of the construction efficiency compared to commonly use...
Citations
... There has been increased interest in using recycled materials resulting from large volumes of generated construction wastes during the last couple of decades . This represents a workable approach in Naik and Moriconi (2005) to reduce the carbon footprint of the concrete venture (Nasr et al., 2020;Oh et al., 2021;Wang et al., 2021). Additionally, the (EnF) concrete has been significantly assessed by experimental and mathematical methods as a key element in sustainable construction (Abdulmatin et al., 2019;Hilal et al., 2020). ...
... It has been demonstrated that recycled aggregates improve pore dispersion as well as frost resistance (Wei et al., (2019). Agricultural waste has also been studied to improve the qualities of concrete, especially while mixing with silica fume (Nasr et al., (2020). Also, their prospective use in concrete manufacturing as industrial byproducts such as calcium carbide residue has been evaluated Wang et al., 2021). ...
Recycled aggregate is becoming a sustainable construction resource that minimizes the carbon footprint in concrete structures. To predict the behavior of environmentally friendly (EnF) concrete in sustainable construction, it is necessary to predict the compressive strength using recycled materials accurately. The current research highlights the performance of the Deep Learning Neural Network (DLNN), Random Forests (RFs), and Multivariate Adaptive Regression Splines (MARS) are evaluated and extensive analysis of data segmentation was performed by splitting the dataset used in this study into 75–25% as well as 80–20% training/testing scenarios using Extreme Gradient Boosting (XG Boost), a quantitative measurement of the effect of data segmentation on model efficiency. The combination of AI models with Extreme Gradient Boosting (XG Boost) was employed to ascertain the governing variables on the CS prediction. Numerous statistical models developed were used to compare the effectiveness of these given models showing the best performance of the DLNN model based on the least RMSE (2.93). The results found that more variables should be added to the prediction problem for better prediction accuracy and the data split of 80–20% was the best choice. Based on the high accuracy of models, the results demonstrated that over the other established models, the DLNN model surpasses them in the analysis of concrete behavior and is useful for future applications.
... Mortar or concrete's bulk density is defined by a number of factors, such as the amount and density of aggregate, the amount of water and cement, and the presence or absence of trapped or entrained air spaces [72]. Fig. 11 shows how the density of RCA concrete mixtures is impacted by the concrete's age and the UFCe replacement ratio. ...
... The outcomes for bulk density are displayed in Figure 10. The bulk density of hardened mortar or concrete is determined by many factors, including the presence of trapped or incorporated air spaces, the quantity and density of the aggregate, and the cement and water percentage [97]. The outcomes showed two trends. ...
This study investigates the effectiveness of replacing the cement with 0, 5, 10, 15, and 20 wt.% of ceramic waste powder (HCCP) to improve the performance of recycled aggregate concrete (RCA) prepared using 25 wt.% wall tile ceramic coarse aggregates. The slump, initial and final setting time, compressive strength, splitting tensile strength, flexural strength, electrical resistivity, bulk density, porosity, total and surface water absorption, pH level, ultrasonic pulse velocity, dynamic elastic modulus, chloride ion diffusion coefficient, chloride penetration depth, microstructure analysis, and environmental assessment properties were investigated. The results showed that replacing cement with HCCP by 5 to 20 wt.% prolonged the setting time and improved all hardened properties. The highest improvements in mechanical properties were observed at 5 wt.% HCCP, with increasing rates of 26.5%, 22%, and 22.4% at 90 days for compressive strength, tensile strength, and flexural strength, respectively. On the other hand, the optimum enhancement for the durability, microstructural, and environmental efficiency properties was recorded at a 20 wt.% HCCP replacement rate. However, the strength at this ratio tended to decrease but remained higher than that of the control RAC. For instance, the total water absorption, surface water absorption, void ratio, chloride penetration depth, and migration coefficient were reduced by 47%, 45%, 38%, 62.3%, and 55.52%, respectively, compared to the reference sample.
... Peat depth can reach 16 meters. Peat consists of organic fragments from vegetation that have changed and fossilized chemically, the accumulation of this organic material forms peat soil [2]. ...
Foam mortar is a substitute for sub-base layers and base layers in road pavement construction on peat soil, which has the advantages of lightness, strength, and self-compacting. Sand is one of the building blocks of foam mortar. The purpose of the study was to analyze the effect of the gradation of sand on the resulting physical and mechanical properties of foam mortar (foam concrete). In this research, six gradations of sand were made (gradations of 3 sand sources and 3 gradations based on pusjatan standards) and then used in the manufacture of foam mortar and analyzed for volumetric weigh and compressive strength. Foam mortar from the six gradations of sand, it is concluded that gradation no. 6 (lower limit of pusjatan gradation) with a value of volumetric weigh is 0.97 t/m ³ does not float perfectly in water, and no. 1 to 5 (gradation of 3 sand sources and 2 gradations of Pusjatan upper limit and middle) with a volumetric weigh is 0.83 t/m ³ - 0.93 t/m ³ floats in water. The compressive strength values of the 6 gradations are above 2000 kPa and can be used as foundation layers in road pavements.
... However, its cost may constrain its utility in treating substantial volumes of polluted water due to its limited ability to be regenerated, and the activation process may introduce various chemicals into the activated carbon. Consequently, several researchers have explored alternative, cost-effective adsorbents, with a preference for naturally occurring green materials and locally available waste resources [2,26,39]. Green adsorbents are biodegradable, biocompatible, and renewable, rendering them more efficient in eliminating dyes from wastewater than commercial activated carbon. Further, the significant increase in the volume of waste produced from various sources has prompted its utilization for environmental purposes. ...
There has been substantial research focused on developing environmentally friendly materials to remove pollutants from wastewater. In this regard, a key study area is focused on green materials derived from plants and agricultural wastes. These materials have shown promising results in removing pollutants from water, providing a sustainable solution for wastewater treatment. Additionally, using plant-based materials has helped reduce reliance on traditional chemical-based methods, contributing to a more environmentally friendly approach. The current study investigated the efficacy of utilizing pomegranate skin (PG) and date pedicels (DPd) as potential green adsorbents for the elimination of synthetic dye Yellow Bemacid (YB) from aqueous solutions. The investigation involved adsorption tests conducted under various experimental conditions, such as contact time, solution pH, initial dye concentration, and temperature. The obtained findings manifested that both PG and PdD exhibited considerable adsorption capacities for YB, quantified at 20.75 mg/g and 12 mg/g, respectively. The Langmuir model exceptionally fit the experimental data, and the adsorption kinetics closely followed the pseudo-second-order model for both materials studied. The thermodynamic parameters unveiled that the adsorption of YB was a feasible, spontaneous, and endothermic process, with enthalpy (ΔH) values of 2.330 and 4.165 kJ/mol for PG and PdD, respectively. Furthermore, the favourable affinity between the materials PG, PdD, and the YB molecules was indicated by the positive values (0.010 and 0.014 kJ/mol.K ) of entropy (∆S⁰). Lastly, the negative values of the free enthalpies (∆G⁰ < 0) for the studied systems signified the spontaneity of the adsorption process.
... The UPV can be used to evaluate the presence of voids, the quality of the concrete, the efficiency of crack repair, and the durability of the concrete [45]. According to BS 1881: Part 203, the classification of the concrete quality rating for the GRC mix was found to be "Good" [46]. ...
... The water absorption test measures the capillary forces that cause fluids to be drawn into the material's body by its pore structure. The degree to which mortar mixes are waterproof or watertight determines how much water they absorb [45]. The water absorption rate for each mix designation is displayed in Fig. 15. ...
Concrete is a significant construction material, with a 25% increase in production by 2030. However, rapid industrialization and urbanization have made it non-sustainable due to the use of ordinary Portland cement (OPC). OPC production requires extensive energy and resources and causes greenhouse gas emissions. To promote sustainable development, the construction industry is now seeking alternative raw materials, like reusing waste from infrastructure and buildings. The use of recycled cement as a substitute for OPC has been the subject of recent research. Considering this, the main goal of this study was to determine how using ground recycled concrete cement (GRC) as a partial cement substitution affects the fresh, mechanical, microstructure, and durability properties of mortar. To achieve this goal, several tests were performed after a thorough preliminary analysis. GRC particles lack smoothness and have irregular edges, affecting mortar workability. Nonetheless, the 10% replacement improves mechanical and durability performance and has comparable structural compactness to reference mortar, particularly for the latter ages.
... It was found that the compressive strength of PC-WAAC specimens after carbonization curing was higher than that of PC specimens, and the optimum content of WAAC was 20%. Nasr et al. [15] found that adding 10% CCP (autoclaved aerated concrete block waste powder) could produce sustainable mortar, and the compressive strength was improved without a significant impact on other properties of the mortar. They used waste aerated concrete block powder to replace cement (<0.075 mm) or sand (0.075-0.15 mm) in mortar. ...
The purpose of this research is to investigate the utilization potential of recycled powder made from spent coffee grounds (SCGs) and aerated concrete blocks (ACBs) in green-growing concrete. The green-growing concrete is prepared using ACB powder and SCG ash as raw materials instead of 5%, 15%, and 25% and 5%, 10%, and 15% cement, respectively. Then, the two raw materials are compounded with the optimal content. The compressive strength and alkalinity of green-growing concrete at 7d and 28d and the frost resistance after 25 freeze–thaw cycles at 28d are studied. The results showed that the optimum content of ACB powder and SCG ash was 5%. Replacing 5% cement with recycled powder could improve the strength of concrete. The alkalinity of concrete containing ACB powder gradually increased, while the alkalinity of concrete containing SCG ash gradually decreased. The alkalinity of ACB-SCG powder was lower than that of ACB powder but slightly higher than that of SCG ash. The frost resistance of concrete containing ACB powder decreased gradually, and the frost resistance of concrete containing SCG ash increased first and then decreased greatly. The frost resistance of ACB-SCG powder could neutralize that of ACB powder and SCG ash.
... The bulk density of hardened mortar or concrete is affected by the amount of trapped or entrained air spaces, the quantity and density of aggregate, as well as the cement and water content (Nasr et al., 2020). Figure 8 shows the bulk density of mortar for different curing ages. ...
... The UPV may be used to assess the presence of voids, concrete quality, crack healing effectiveness, and concrete durability (Nasr et al., 2020). To acquire the influence of curing days and to lessen the effect of different-sized mortar, three cubes were utilized to examine the UPV of mortar for each mix and all curing ages. ...
The main objective of this study was to examine the combined effect of ground recycled concrete cement (GRC) and thermo-activated recycled concrete cement (TARC) on properties of mortar. The physical, chemical and microstructural tests were conducted to characterize GRC and TARC before mortar mixtures were produced. The microscopic morphology of GRC and TARC revealed uneven edges and a rough surface that is slightly porous. The GRC and TARC powders were used to replace cement in the range of 0-50% at increments of 10% by volume. The fresh, mechanical, microstructure, and durability characteristics of mortar were tested for different proportion of GRC and TARC as partial replacement of cement. The usage of GRC and TARC decreases the workability of mortar marginally. However, the mechanical performance of the mortar mixtures showed an increasing trend when GRC and TARC share increases in the mixture. Predominantly, compressive strength, bulk density, and ultrasonic pulse velocity (UPV) have all been increased by as much as 20% cement replacement. Furthermore, the incorporation of GRC and TARC enhances the mortar’s durability properties. The microstructure analysis reveals that 20% replacement (GT20) mix has superior structural compactness. In general, partially substitution of GRC and TARC by ordinary Portland cement improves several characteristics of mortar. This will help solve the most prevalent problems that concrete produces, including the high embedded carbon dioxide creation, the high resource usage, and the high waste generation after demolition.
... SCMs can be employed either independently or in conjunction with one another in concrete. Introducing supplementary cementitious materials (SCMs) into concrete mixtures to create blended self-compacting concrete mixes can improve the qualities of the concrete in both its early and final stages [37,38,39]. Utilising them can enhance the workability, strength, and durability of self-compacting concrete. ...
... One of the most excessively utilized building materials is the concrete [1][2][3]. However, there are some characteristics that affect its durability during the service life, such as the shrinkage [4]. ...
