Plastic waste is an undeniable source of pollution that threatens the existence of the earth’s flora and fauna. The bulk of plastic waste generated globally does not go through the proper methods of ...disposal but is carelessly discarded into the aquatic or terrestrial environment. Current recycling efforts are largely inadequate and disposal in landfills is still fraught with environmental and land use challenges. The proper disposal of plastic waste, as well as mitigating the environmental, social, and health impacts of extracting natural aggregates can be achieved by incorporating plastic waste as aggregates in the construction industry. This paper presents a characterization of aggregates manufactured from polyethylene terephthalate plastic waste using thermal/mechanical methods. From the cost analysis, 24,341.67 Ugx (6.09 USD) was spent to produce 1 kg of PET aggregates. Morphological, intrinsic and mechanical characteristics of the produced aggregates were established using standard procedures and equipment. The results of morphological characterization indicate an irregular shaped aggregate with smooth surface, a dense graded aggregate with a fineness modulus of 4.25, flakiness index of 26%, elongation index of 16% and particle index of 13. Intrinsic characterization yielded particle density of 1330 kg/m
3
, bulk density of coarse aggregates of 715 kg/m
3
and water absorption of 0.445%. Mechanical characteristics of aggregates were evaluated, with compressive strength of 50Mpa, Aggregate Crushing Value of 37%, Ten Percent Fines Value of 71KN, Aggregate Impact Value of 24% and Aggregate Abrasion Value of 20%. The characteristics of PET aggregates confirm their suitability for application in structural lightweight concrete and rigid pavement. The produced PET aggregates can be considered in mix design as a total or partial replacement of natural aggregates in concrete.
The main objective of this article is to evaluate the potential use of wood ash as a substitute for cement and sand in mortars. Three types of wood were selected: Ayous, Sapelli and Fraké, all of ...which were sourced from carpentry in Cameroon. The sawdust was dried and combusted to obtain ash, then ground and sieved. Six types of mortar were produced, with cement substitution at 0%, 5%, 10%, 15%, 20% and 25%. The physico-mechanical properties of these substitutions were determined after 7, 28 and 56 days. The results of the cement paste consistency show that it increases with the addition of ash, due to the fact that sawdust ash requires a large quantity of water. The addition of ash caused an increase in setting time due to the fact that sawdust ash is less reactive than Ordinary Portland cement, resulting in a delay in the rate of cement hydration. Apparent density values decreased with the addition of sawdust ash, probably due to the hygroscopic behavior of type of ash in mortar specimens. The highest pozzolanic index is that of 5% replacement by ash and almost identical absorption for all mortars at this substitution percentage. Acid attack results revealed a higher durability of mortar specimens with the higher percentage of ash substitution. Optimum compressive strengths for the different substitution percentages were observed at 5%, 15% and 10% respectively for Ayous, Sapelli and Fraké. The best wood ash is Sapelli because of its chemical composition and resistance to compression in mortars. At 56 days, compressive strength values exceed those of the reference composition. This may be due to pozzolanic reactions in the mortars of ash.
Plastic waste has become a pressing global issue, posing significant environmental challenges. As the construction industry continues to grow, there is a growing need for sustainable construction ...materials that can address this problem. This review paper focuses on the transformation of waste into innovation by exploring the use of plastic bricks as sustainable construction materials. The paper examines the manufacturing processes, properties, environmental benefits, challenges, case studies, and future research directions associated with plastic bricks. It highlights the potential of plastic bricks to reduce plastic waste, carbon emissions, and resource consumption. Additionally, the review addresses the challenges related to structural integrity, long-term durability, regulatory compliance, and public perception. Case studies showcase successful implementations of plastic bricks in construction projects, emphasizing their innovative design possibilities, cost-effectiveness, economic feasibility, and notable structural strength. These case studies illustrate that plastic bricks can achieve the necessary strength for construction applications, making them a viable alternative to traditional materials. The paper also discusses the environmental impact and circular economy perspectives of plastic bricks, highlighting their recyclability, reusability, waste management implications, and contribution to circular economy initiatives. Finally, the review concludes with future research directions and recommendations, focusing on advancements in manufacturing techniques, enhanced performance and engineering properties, and long-term performance monitoring and assessment. This comprehensive review sheds light on the transformative potential of plastic bricks as sustainable construction materials and provides insights for addressing the global plastic waste problem.
This study aims to introduce a comprehensive methodology for optimizing complete real structural systems for roofs involving trusses, purlins, and bracing systems jointly, taking into account ...realistic loads and constraints dictated by technical codes, thereby offering a more accurate representation of practical scenarios. The objective is to achieve the minimum mass through size, shape, and topology optimization of both the main truss and purlin structural subsystems. To achieve this goal, the Enhanced Particle Swarm Optimization (EPSO) algorithm is implemented. An example of a realistic case, which takes into account multiple actual constraints such as stress, displacement, buckling, and natural frequency limits, is thoroughly evaluated. After that, 144 other interactions among dimensions of the building and loads applied are simulated, and the mass of the system is obtained for each one of them. The results indicated that the graphs generated from the various simulations allow for the determination of the optimized mass for different building dimensions. Consequently, the cost and raw material consumption can be estimated for common applications. Therefore, it is concluded that this work presents a significant contribution to structural designers, as the proposed methodology enables structural optimization quickly and easily for practical engineers.
In building construction, seepage and dampness in walls present serious problems since they can cause structural failures and damage in both residential and commercial contexts. Finding more ...affordable options is necessary as mitigating these problems frequently requires expensive fixes. This study aims to evaluate the effects of solvothermal-treated polyethylene added at concentrations ranging from 0 to 1.0% on the mechanical properties of concrete and sandcrete blocks. In addition to assessing the workability, split tensile strength, and compressive strength of concrete samples at different levels of the polyethylene (PE) inclusion, the study looked into the water absorption capacity, density, and compressive strength of sandcrete blocks. The blocks’ compressive strength and water absorption capacity reduced as the amount of polyethylene additives rose, although there was a slight increase in the density. These changes remain well within the Nigerian Industrial Standards’ specified limits. Hardened concrete shows a drop in density, compressive strength, and split tensile strength with increasing polyethylene content, while fresh concrete's workability decreases as the percentage increases. 0.4% incorporation of the treated polyethylene achieved the target strength of 20 N/mm
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while Sandcrete blocks with up to 1% of the solvothermal treated polyethylene had compressive strengths more than the 2.5 N/mm
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minimum required for non-load-bearing walls. About 61% reduction in water absorption was achieved in 48 h by the blocks, presenting a promising and cost-effective solution for seepage-related issues in building construction.
This paper presents a comprehensive Discrete Element Method (DEM) calibration program designed for optimal calibration of hot mix asphalt (HMA) in full-scale paving applications. The program allows ...for the calibration of various asphalt mixes and allows for studies such as how tamper stroke affects pre-compaction based on the calibrated HMA. The study identifies key pavement properties essential to the paving process, including pre-compaction resistance, flow behavior, and friction behavior between HMA and steel or asphalt surfaces, and details their laboratory-based evaluation methods. A contact model that incorporates realistic plastic deformation, adhesive forces, and multiple load cycles is presented in this research. Novel features include a two-clump particle shape system and a two-grain distribution for the grading curve. These parameters, combined with the contact model, facilitate the observation of particle orientations and segregations, ensuring an economical yet robust full-scale simulation. Validation included testing and calibration of three different asphalt mixes (Asphalt Concrete (AC) 11 DS, Stone Mastic Asphalt (SMA) 11 DS, and AC 16 BS). The results demonstrate the successful calibration of all relevant pavement properties using the prescribed methodology and settings. This study advances the understanding of HMA pavement properties and provides a practical framework for optimal calibration in full-scale paving scenarios.
Crack propagation can be affected by the holes of the placement of rebars in the reinforced concrete and the resulting changes in the homogeneous structure of concrete. This experimental study aimed ...at investigating the fiber self-compacting concrete failure and crack propagation in concrete specimens with circular central holes and contain 2, 4, and 8 fiber percentages. The crack propagation mechanisms under the uniaxial compressive strength of the concrete were studied by investigating the holes created by rebars buried in the reinforced concrete. Three concrete mix designs with different compressive strengths of 27, 30, and 33 MPa were used for detailed analysis of the fiber concrete behavior by 224 standard 150 mm cubic specimens. The results showed the insignificant impact of small holes with an approximate area of 1.4% of the specimen surface area on the failure structure so that crack propagation in this case was similar to that occurred in the hole-free concrete. The compressive strength of concrete decreased, by increasing the crack prorogation around the holes. The compressive strength of the concrete may be reduced significantly by increasing the hole diameter. Taking into account these factors in the design of the connection core can reduce the compressive strength of concrete by 30% depending on the rebar grid.
Peat soil presents significant challenges for construction due to its inherent weak properties, including high water content, limited permeability, low shear Strength, low specific gravity, and ...acidity. Despite the potential of Mg-rich synthetic gypsum (MRSG) to improve soil properties, research on its use for stabilising severely poor peat soils is limited. This study addresses this gap by investigating the efficacy of MRSG in peat soil stabilisation using a novel multi-layering backfill approach. The methodology includes soil classification of peat soil. And, to understand the mechanical and chemical changes of stabilized peat soil, the unconfined compressive Strength (UCS) testing and microstructural analysis using SEM, EDX, and XRD before and after stabilisation are studied. Peat samples were treated with MRSG through backfilling method in 5, 7, and 9 layers and evaluated the strength increment after curing periods of 7, 28, and 60 days. Results demonstrate that MRSG significantly enhanced the compressive strength, increasing it to 210.33 kPa as early as 7 days for 9 layers of backfill incomparable with the untreated soil strength of 51.87 kPa. The new cementitious product in the soil known as ettringite was observed from SEM analysis and confirmed by the EDX and XRD analysis. By recycling industrial byproducts, this environmentally friendly method encourages sustainability and lessens dependency on raw resources, which is important for infrastructure construction and other projects in areas rich in peat.
This paper takes place in improving the energy performance assessment of cob buildings, by evaluating thevariability of its hygrothermal properties at the material scale, related to the traditional ...construction process. Forso, we proposed and analysed data to handle the variability of the hygrothermal properties. The specimens weremanufactured using a moulding method representative of on-site cob wall manufacturing process, for three plants species (hemp shiv, flax yarn and hay stalk) and three fibre content (0, 1% and 3%). Using non-destructivetests and statistical analysis, the random variability of cob composites hygrothermal properties (density, thermalconductivity, specific heat capacity, water-vapor permeability, moisture buffering value and sorption isotherms)was found as well as the variability distribution. It has been shown that the variability of properties is sensitive tothe nature of plant fibres specie and the fibre content. Using the variability indicators, it has been found on thermal conductivity, a low coefficient of variation of 2.88% for 1%-flax fibred mixture (lower than unfibred material) and a high one for 3%-hemp composites of 10.88%. The variability of sorption isotherms was usually found to be high at lower humidity loads. It has been shown that increase fibre content stabilizes the variability of properties. Moreover, some evolution trends of the variability according to mixes was proposed; two parameters were found: the first, either FCmax highlighting the fibre content for which the maximum of variability was achieved or FCmin for the opposite; the second is FCres highlighting the residual variability, for high fibre content. The distribution of properties were found to be generally centered.
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