| 1. |
- Abuhussain, Mohammed Awad, et al.
(författare)
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Data-driven approaches for strength prediction of alkali-activated composites
- 2024
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Ingår i: Case Studies in Construction Materials. - : Elsevier. - 2214-5095. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Alkali-activated composites (AACs) have attracted considerable interest as a promising alternative to reduce CO2 emissions from Portland cement production and advance the decarbonisation of concrete construction. This study describes the data-driven predictive modelling to anticipate the compressive strength (CS) of AACs. Four different modelling techniques have been chosen to forecast the CS of AACs using the selected data set. The decision tree (DT), multi-layer perceptron (MLP), bagging regressor (BR), and AdaBoost regressor (AR) were employed to investigate the precision level of each model. When it comes to predicting the CS of AACs, the results show that the AR model performs better than the BR model, the MLP model, and the DT model by providing a higher value for the coefficient of determination, which is equal to 0.91, and a lower MAPE value, which is equal to 13.35%. However, the accuracy level of the BR model was very near to that of the AR model, with the R2 value suggesting a value of 0.90 and the MAPE value indicating a value of 14.43%. Moreover, the graphical user interface has also been developed for the strength prediction of alkali-activated composites, making it easy to get the required output from the selected inputs.
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| 2. |
- Awoyera, Paul O., et al.
(författare)
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Structural retrofitting of RC slabs using bamboo fibre laminate: Flexural performance and crack patterns
- 2024
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Ingår i: Heliyon. - : Elsevier. - 2405-8440. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing the durability of structural elements is a viable approach to promote sustainability in civil engineering. Research has shown that well-maintained slabs outperform degraded ones, which deteriorate rapidly due to insufficient upkeep. The occurrence of cracking and deformation in slabs subjected to sustained loads significantly impacts their functionality. However, the implementation of appropriate retrofitting techniques utilizing locally available materials can effectively minimize deflection and crack propagation while also improving flexural capacity. This particular study aimed to evaluate the flexural performance of slabs that were retrofitted using bamboo fibre laminate (BFL). Also, the study investigated two alternative replacement methods alongside the conventional mix; one involved replacing all fine aggregates with ceramic fine aggregate and the other involved a complete replacement of coarse aggregates with ceramic coarse aggregate. These mixes were represented in both the retrofitted and non-retrofitted samples. The retrofitting process included using the combined external bonding and near surface-mounted method. Twelve slab samples were made, with six being non-retrofitted and the other six retrofitted with BFL. Each of the samples had dimensions of 300 mm × 300 mm × 50 mm for reinforced concrete (RC) slabs. The slabs were tested employing the three point-bending system, and the retrofitted slabs with the conventional mix exhibited the highest ultimate failure load and flexural strength (62.1 kN), which compared to the non-retrofitted slabs of the same mix was a 60.76% increase. Additionally, the study did a thorough analysis of the presence of flexural and diagonal shear cracks, as well as the occurrence of debonding between BFL and the slabs. Non-destructive tests were also conducted on the slab samples to further confirm accurate results. These findings offer helpful insights into the development and application of a sustainable retrofitting material that can remarkably improve RC slabs.
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| 3. |
- Mydin, Md Azree Othuman, et al.
(författare)
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Residual durability, mechanical, and microstructural properties of foamed concrete subjected to various elevated temperatures
- 2024
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Ingår i: Engineering Science and Technology, an International Journal. - : Elsevier. - 2215-0986. ; 55
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Tidskriftsartikel (refereegranskat)abstract
- Three different densities (500 kg/m3, 1000 kg/m3, and 1500 kg/m3) of foamed concrete (FC) were tested alongside mortar with a density of 1980 kg/m3 to investigate how high temperatures affect the qualities of FC. A flow table test was used to examine the fresh qualities of the mixtures. The modulus of elasticity, ultrasonic pulse velocity (UPV), bending strength, split tensile strength, compressive strength, thermal conductivity, porosity, and appearance and colour changes at ambient temperature and after exposure to various high temperatures (100 ◦C, 150 ◦C, 200 ◦C, 400 ◦C, 600 ◦C, and 800 ◦C) were evaluated. To study the effects of varying densities, microstructure analysis was performed utilizing scanning electron microscopy and mercury intrusion porosimetry. According to the findings, the four varied densities appeared dissimilar. FC with lower densities (500 kg/m3 and 1000 kg/m3) showed signs of cracking, while FC with a higher density (1500 kg/m3) enabled for precise detection of the pore connectivity and surface spalling occurrences. High temperatures had less effect on the mortar than FC mixtures. As the temperature increased, the modulus of elasticity, split tensile strength, bending strength, compressive strength, thermal conductivity, and mass loss decreased for all the mortar and FC samples. The UPV values increased marginally up to 100 ◦C before decreasing. This investigation highlighted the need for additional research and code provisions that consider different innovative construction materials and FC constituent classes.
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| 4. |
- Wang, Jing, et al.
(författare)
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Experimenting the influence of corncob ash on the mechanical strength of slag-based geopolymer concrete
- 2024
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Ingår i: Reviews on Advanced Materials Science. - : Walter de Gruyter GmbH. - 1606-5131 .- 1605-8127. ; 63:1
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Tidskriftsartikel (refereegranskat)abstract
- The construction sector has been under growing public attention recently as one of the leading causes of climate change and its detrimental effects on local communities. In this regard, geopolymer concrete (GPC) has been proposed as a replacement for conventional concrete. Predicting the concrete’s strength before pouring is, therefore, quite useful. The mechanical strength of slag and corncob ash (SCA–GPC), a GPC made from slag and corncob ash, was predicted utilizing multi-expression programming (MEP). Modeling parameters’ relative importance was determined using sensitivity analysis. When estimating the compressive, flexural, and split tensile strengths of SCA–GPC with MEP, 0.95, 0.93, and 0.92 R2-values were noted between the target and predicted results. The developed models were validated using statistical tests for error and efficiency. The sensitivity analysis revealed that within the mix proportions, the slag quantity (65%), curing age (25%), and fine aggregate (3.30%) quantity significantly influenced the mechanical strength of SCA–GPC. The MEP models result in distinct empirical equations for the strength characteristics of SCA–GPC, unlike Python-based models, which might aid industry and researchers worldwide in determining optimal mix design proportions, thus eliminating unneeded test repetitions in the laboratory.
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| 5. |
- Zhou, Yi, et al.
(författare)
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An overview of recent advancements in fibre-reinforced 3D printing concrete
- 2023
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Ingår i: Frontiers in Materials. - : Frontiers Media SA. - 2296-8016. ; 10
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Forskningsöversikt (refereegranskat)abstract
- 3D printing, also known as additive manufacturing, has recently gained significant attention and popularity as a transformative technology across various industries. One area where 3D printing is making remarkable strides is in the construction field, particularly with the emergence of 3D printing concrete (3DPC). While 3DPC holds immense promise, there are still challenges to overcome, such as incorporating reinforcement. This study reviews the potential of using fibre reinforcement to overcome the challenge of making ductile concrete for 3D printing that can withstand substantial tensile stresses. Effects of various types of fibre addition on widespread aspects of 3DPC are systematically reviewed. This review study considers various aspects of 3DPC: rheological characteristics, buildability, anisotropic mechanical behavior, and ductility. These characteristics of fibre-reinforced 3DPC are discussed in light of the published literature. This research’s graphical and statistical visualizations offer valuable insights for academic scholars. This review summarizes recent advancements in fibre-reinforced 3DPC while highlighting the persisting challenges in developing fibre-reinforced 3DPC with desired properties for real-world applications.
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