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  • 1
    In: Buildings, MDPI AG, Vol. 12, No. 8 ( 2022-07-25), p. 1085-
    Abstract: Fiber-reinforced polymers poles were on the increase because they were lightweight, have high strength-to-weight ratios, provide corrosion resistance, can be customized to meet strength and deflection requirements, and have a low life-cycle cost of construction and maintenance. This research presents a comprehensive review of all significant research and existing case studies to review the present knowledge concerning fiber-reinforced polymers poles. The main summary covers 70 works focusing on fiber poles to summarize recent activities on selected relevant topics and highlight possible future implementations. In this context, this study discusses fiber-reinforced polymers poles in six aspects: (i) introduction; (ii) methodology; (iii) Materials properties of FRP poles; (iv) manufacturing techniques of FRP poles; (v) testing of FRP poles (static and dynamic flexure test as cantilever beam); (vi) modeling of FRP poles. Therefore, this critical review will demonstrate an overview of FRP Poles manufacturing techniques (Pultrusion, filament winding, centrifugal process, and hand lay-up) and which Pultrusion technique is the best suited for FRP Poles. Static modeling was the most used of other techniques.
    Type of Medium: Online Resource
    ISSN: 2075-5309
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661539-3
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  • 2
    Online Resource
    Online Resource
    Ital Publication ; 2023
    In:  Civil Engineering Journal Vol. 9, No. 8 ( 2023-08-01), p. 1912-1921
    In: Civil Engineering Journal, Ital Publication, Vol. 9, No. 8 ( 2023-08-01), p. 1912-1921
    Abstract: Although GFRP poles are widely accepted today due to their low cost and weight and high electrical and corrosion resistance, they suffer large deformations due to the low elastic and rigidity moduli (E & G) values of the GFRP. Accordingly, it is essential to accurately measure these values to estimate the actual deformation of the pole. This study presented a procedure to measure (E & G) values using three different tests on three sample sizes: full, scale pole, conic sample, and ad coupon sample, instead of using the manufacturer values as usual. This study is also concerned with the shear modulus value and when it can be neglected as usual in other traditional materials. The GRG optimization technique was used to analyze the results and determine the optimum values for (E & G) considering the results of the three tests. The results showed that the values of (E & G) are greatly affected by the sample’s size and shape, the slenderness ratio of the sample (L/r), and the shear deformation contribution. The critical slenderness ratio (L/r), corresponding to a shear deformation contribution of 10%, was determined for each test. This value is recommended as the upper boundary for any test that measures the (E & G) values. Testing several samples with different (L/r) values is also recommended to enhance accuracy. This study was concerned with determining the optimum values of elastic and rigidity moduli for GRFP poles compared to the manufacturer’s conservative values. The results indicated that the shear modulus can be neglected and the importance of the scale effect on the results of flexure and shear modulus. Doi: 10.28991/CEJ-2023-09-08-07 Full Text: PDF
    Type of Medium: Online Resource
    ISSN: 2476-3055 , 2676-6957
    Language: Unknown
    Publisher: Ital Publication
    Publication Date: 2023
    detail.hit.zdb_id: 2844355-X
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  • 3
    In: Advances in Civil Engineering, Hindawi Limited, Vol. 2023 ( 2023-4-18), p. 1-15
    Abstract: As construction activity continues to increase on a daily basis, the demand for fine and coarse aggregates is also rising. However, relying on a few sources would quickly deplete the natural sources of aggregates. In Lahore, Punjab, Pakistan, costly coarse pit sand from northern areas is used for concrete, as the local river sands (Ravi and Chenab) are fine and do not meet ASTM specifications for fine aggregates. To alleviate the pressure on one source, it is necessary to improve the gradation of natural river sand by utilizing quarry dust obtained during the process of crushing rock into crushed stones. This study conducted detailed experimental work to enhance the gradation of natural river sand by adding normalized quarry dust. Concrete mixes with three strengths of 21 MPa, 28 MPa, and 35 MPa were prepared by partially replacing natural river sand with quarry sand. Workability and hardened concrete properties were evaluated for all mixes, and cost analysis was performed for 28 MPa concrete. The results were compared with control concrete made with coarse pit sand. When river sand was enhanced by combining 40% river sand and 60% normalized quarry dust, the resulting sand met ASTM requirements. Furthermore, when some fines were removed from river sand and replaced with 50% normalized quarry dust, the sand also met ASTM grading requirements. The compressive and flexural strengths of concrete made with enhanced sand gradation increased by 10–25% and 9–17%, respectively, for 28 MPa concrete compared to the control concrete. Cost analysis showed that 28 MPa concrete made with enhanced natural river sand gradation was 8.6% more economical than concrete made with coarse pit sand.
    Type of Medium: Online Resource
    ISSN: 1687-8094 , 1687-8086
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2023
    detail.hit.zdb_id: 2449760-5
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  • 4
    In: Materials, MDPI AG, Vol. 15, No. 10 ( 2022-05-17), p. 3584-
    Abstract: Recycled rubber waste (RW) is produced at an alarming rate due to the deposition of 1.5 billion scrap tires annually around the globe, which causes serious threats to the environment due to its open land filling issues. This study investigates the potential application of RW in concrete structures for mitigating the alkali–silica reaction (ASR). Various proportions of RW (5%, 10%, 15%, 20%, and 25%) partially replaced the used aggregates. RW was procured from a local rubber recycling unit. Cubes, prisms, and mortar bar specimens were prepared using a mixture design recommended by ASTM C1260 and tested for evaluating the compressive and flexural strengths and expansion in an ASR conducive environment for specimens incorporating RW. It was observed that the compressive and flexural strength decreased for specimens incorporating RW compared to that of the control specimens without RW. For example, an 18% and an 8% decrease in compressive and flexural strengths, respectively, were observed for specimens with 5% of RW by aggregates volume at 28 days. Mortar bar specimens without RW showed an expansion of 0.23% and 0.28% at 14 and 28 days, respectively, indicating the potential ASR reactivity in accordance with ASTM C1260. A decrease in expansion was observed for mixtures incorporating RW. Specimens incorporating 20% of RW by aggregate volume showed expansions of 0.17% at 28 days, within the limit specified by ASTM C1260. Moreover, specimens incorporating RW showed a lower reduction in compressive and flexural strengths under an ASR conducive environment compared to that of the control specimen without RW. Micro-structural analysis also showed significant micro-cracking for specimens without RW due to ASR. However, no surface cracks were observed for specimens incorporating RW. It can be argued that the use of RW in the construction industry assists in reducing the landfill depositing issues with the additional benefit of limiting the ASR expansion.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2487261-1
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  • 5
    In: Materials, MDPI AG, Vol. 15, No. 15 ( 2022-08-07), p. 5435-
    Abstract: The mechanical properties of concrete are the important parameters in a design code. The amount of laboratory trial batches and experiments required to produce useful design data can be decreased by using robust prediction models for the mechanical properties of concrete, which can save time and money. Portland cement is frequently substituted with metakaolin (MK) because of its technical and environmental advantages. In this study, three mechanical properties of concrete with MK, i.e., compressive strength (f′c), splitting tensile strength (fst), and flexural strength (FS) were modelled by using four machine learning (ML) techniques: gene expression programming (GEP), artificial neural network (ANN), M5P model tree algorithm, and random forest (RF). For this purpose, a comprehensive database containing detail of concrete mixture proportions and values of f′c, fst, and FS at different ages was gathered from peer-reviewed published documents. Various statistical metrics were used to compare the predictive and generalization capability of the ML techniques. The comparative study of ML techniques revealed that RF has better predictive and generalization capability as compared with GEP, ANN, and M5P model tree algorithm. Moreover, the sensitivity and parametric analysis (PA) was carried out. The PA showed that the most suitable proportions of MK as partial cement replacement were 10% for FS and 15% for both f′c and fst.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2487261-1
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  • 6
    Online Resource
    Online Resource
    Ital Publication ; 2023
    In:  Civil Engineering Journal Vol. 9, No. 6 ( 2023-06-01), p. 1389-1401
    In: Civil Engineering Journal, Ital Publication, Vol. 9, No. 6 ( 2023-06-01), p. 1389-1401
    Abstract: Centrifugal-manufactured GFRP pipes are widely used today as lighting and low-power transmission poles due to their lightweight, high electrical insulation, low cost, and corrosion resistance. Despite these advantages, GFRP poles suffer high deflection problems due to their low elastic and shear moduli values. In order to overcome this disadvantage, three techniques were suggested to control the lateral deflection of the GFRP poles: an extended internal steel stub, external steel angles, and internal steel bracing bars. The main objective of this study is to determine the optimum strengthening technique to improve the serviceability of GFRP poles in terms of lateral deflection according to ASTM D4923. An experimental research program containing five full-scale GFRP poles was carried out to determine the optimum strengthening technique and the effect of connectors opening near the base and compare it to previous research. The results indicated that flexural stiffness was increased by 44%, 66%, and 38% for the extended stub, steel angles, and bracing bars, respectively. Besides that, the reduction in flexural stiffness due to connector opening was about 8%. The measured deflections showed good matching with simplified mathematical calculations, and the division was about ±10%. The external steel angle technique showed the best efficiency in Stiffness behavior. Doi: 10.28991/CEJ-2023-09-06-07 Full Text: PDF
    Type of Medium: Online Resource
    ISSN: 2476-3055 , 2676-6957
    Language: Unknown
    Publisher: Ital Publication
    Publication Date: 2023
    detail.hit.zdb_id: 2844355-X
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  • 7
    In: Materials, MDPI AG, Vol. 15, No. 21 ( 2022-11-03), p. 7731-
    Abstract: For the creation of healable cement concrete matrix, microbial self-healing solutions are significantly more creative and potentially successful. The current study investigates whether gram-positive “Bacillus subtilis” (B. subtilis) microorganisms can effectively repair structural and non-structural cracks caused at the nano- and microscale. By creating an effective immobilization strategy in a coherent manner, the primary challenge regarding the viability of such microbes in a concrete mixture atmosphere has been successfully fulfilled. The iron oxide nanoparticles were synthesized. The examined immobilizing medium was the iron oxide nanoparticles, confirmed using different techniques (XRD, SEM, EDX, TGA, and FTIR). By measuring the average compressive strength of the samples (ASTM C109) and evaluating healing, the impact of triggered B. subtilis bacteria immobilized on iron oxide nanoparticles was examined. The compressive strength recovery of cracked samples following a therapeutic interval of 28 days served as a mechanical indicator of the healing process. In order to accurately correlate the recovery performance as a measure of crack healing duration, the pre-cracking load was set at 80% of the ultimate compressive stress, or “f c,” and the period of crack healing was maintained at 28 days. According to the findings, B. subtilis bacteria greatly enhanced the compressive strength and speed up the healing process in cracked cement concrete mixture. The iron oxide nanoparticles were proven to be the best immobilizer for keeping B. subtilis germs alive until the formation of fractures. The bacterial activity-driven calcite deposition in the generated nano-/micro-cracks was supported by micrographic and chemical investigations (XRD, FTIR, SEM, and EDX).
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2487261-1
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  • 8
    In: Buildings, MDPI AG, Vol. 12, No. 5 ( 2022-05-23), p. 693-
    Abstract: The load–deformation relationship under the footing is essential for foundation design. Shallow foundations are subjected to changes in hydrological conditions such as rainfall and drought, affecting their saturation level and conditions. The actual load–settlement response for design and reconstructions is determined experimentally, numerically, or utilizing both approaches. Ssettlement computation is performed through large-scale physical modeling or extensive laboratory testing. It is expensive, labor intensive, and time consuming. This study is carried out to determine the effect of different saturation degrees and loading conditions on settlement shallow foundations using numerical modeling in Plaxis 2D, Bentley Systems, Exton, Pennsylvania, US. Plastic was used for dry soil calculation, while fully coupled flow deformation was used for partially saturated soil. Pore pressure and deformation changes were computed in fully coupled deformation. The Mohr–Columb model was used in the simulation, and model parameters were calculated from experimental results. The study results show that the degree of saturation is more critical to soil settlement than loading conditions. When a 200 KPa load was applied at the center of the footing, settlement was recored as 28.81 mm, which was less than 42.96 mm in the case of the full-depth shale layer; therefore, settlement was reduced by 30% in the underlying limestone rock layer. Regarding settlement under various degrees of saturation (DOS), settlment is increased by an increased degree of saturation, which increases pore pressure and decreases the shear strength of the soil. Settlement was observed as 0.69 mm at 0% saturation, 1.93 mm at 40% saturation, 2.21 mm at 50% saturation, 2.77 mm at 70% saturation, and 2.84 mm at 90% saturation of soil.
    Type of Medium: Online Resource
    ISSN: 2075-5309
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661539-3
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  • 9
    Online Resource
    Online Resource
    Elsevier BV ; 2022
    In:  Environmental Pollution Vol. 306 ( 2022-08), p. 119373-
    In: Environmental Pollution, Elsevier BV, Vol. 306 ( 2022-08), p. 119373-
    Type of Medium: Online Resource
    ISSN: 0269-7491
    RVK:
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2022
    detail.hit.zdb_id: 280652-6
    detail.hit.zdb_id: 2013037-5
    SSG: 12
    SSG: 14
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  • 10
    In: Materials, MDPI AG, Vol. 15, No. 16 ( 2022-08-16), p. 5639-
    Abstract: Biodegradable materials are appropriate for the environment and are gaining immense attention worldwide. The mechanical properties (such as elongation at break, density, and failure strain) of some natural fibers (such as Coir, Hemp, Jute, Ramie, and Sisal) are comparable with those of some synthetic fibers (such as E glass, aramid, or Kevlar). However, the toughness of coconut fibers is comparatively more than other natural fibers. Numerous studies suggest coconut fibers perform better to improve the concrete mechanical properties. However, the knowledge is dispersed, making it difficult for anyone to evaluate the compatibility of coconut fibers in concrete. This study aims to perform a scientometric review of coconut fiber applications in cementitious concrete to discover the various aspects of the literature. The typical conventional review studies are somehow limited in terms of their capacity for linking different literature elements entirely and precisely. Science mapping, co-occurrence, and co-citation are among a few primary challenging points in research at advanced levels. The highly innovative authors/researchers famous for citations, the sources having the highest number of articles, domains that are actively involved, and co-occurrences of keywords in the research on coconut-fiber-reinforced cementitious concrete are explored during the analysis. The bibliometric database with 235 published research studies, which are taken from the Scopus dataset, are analyzed using the VOSviewer application. This research will assist researchers in the development of joint ventures in addition to sharing novel approaches and ideas with the help of a statistical and graphical description of researchers and countries/regions that are contributing. In addition, the applicability of coconut fiber in concrete is explored for mechanical properties considering the literature, and this will benefit new researchers for its use in concrete.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2487261-1
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