Civil Engineering Department, University of Duhok, Duhok, Kurdistan Region, Iraq.
Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia.
PLoS One. 2022 Jul 13;17(7):e0269664. doi: 10.1371/journal.pone.0269664. eCollection 2022.
In recent decades, several studies have considered the use of plastic waste as a partial substitute for aggregate in green concrete. Such concrete has been limited to non-structural applications due to its low strength. This raises whether such concrete can be enhanced for use in some structural applications. This paper reports an attempt to develop a structural-grade concrete containing plastic waste aggregate with high proportions of substitution and confined with carbon fiber reinforced polymer (CFRP) fabrics. Experimental research was conducted involving the casting and testing 54 plain and confined concrete cylinders. A concrete mixture was designed in which the fine aggregate was partially replaced by polyethylene terephthalate (PET) waste plastic at ratios of 0%, 25%, and 50%, and with different w/c ratios of 0.40, 0.45, and 0.55. The results show that confinement has a substantial positive effect on the compressive behavior of PET concrete. The enhancement efficiency increases by 8-190%, with higher enhancement levels for higher substitution ratios. Adding one layer of CFRP fabric raises the ultimate strength of samples that have lost compressive strength to a level close to that of unconfined samples not containing PET. This confinement is accompanied by an increase in the slope of the stress-strain curve and greater axial and lateral strain values at failure. For the specimens confined by CFRP fabric, PET aggregate can be used as a partial substitute for sand at a replacement ratio of up to 50% by volume for structural applications. This paper also considers the ability of existing models to predict the strength of confined-PET concrete circular cross-sections by comparing model predictions with experimental results. The strength of confined PET concrete elements can't be accurately predicted by any of the models that are already out there. It's important to come up with a new model for these elements.
近几十年来，已有多项研究考虑将塑料废物用作绿色混凝土中集料的部分替代品。由于其强度低，此类混凝土仅限于非结构应用。这就提出了这样的问题，即是否可以增强这种混凝土以用于某些结构应用。本文报告了一项开发含有高比例塑料废物集料的结构级混凝土的尝试，该集料采用碳纤维增强聚合物（CFRP）织物进行约束。进行了涉及浇注和测试 54 个普通和约束混凝土圆柱体的实验研究。设计了一种混凝土混合物，其中细集料部分用聚对苯二甲酸乙二醇酯（PET）废塑料代替，替代比为 0%、25%和 50%，水灰比分别为 0.40、0.45 和 0.55。结果表明，约束对 PET 混凝土的抗压性能有显著的积极影响。增强效率提高 8-190%，替代率越高，增强水平越高。添加一层 CFRP 织物可将抗压强度丧失的样品的极限强度提高到接近不含有 PET 的无约束样品的水平。这种约束伴随着应力-应变曲线斜率的增加和破坏时轴向和侧向应变值的增加。对于用 CFRP 织物约束的试件，在体积替代比高达 50%的情况下，PET 集料可用于部分替代砂，用于结构应用。本文还通过将模型预测与实验结果进行比较，考虑了现有模型预测约束-PET 混凝土圆形横截面强度的能力。现有的模型都无法准确预测约束 PET 混凝土构件的强度。为这些构件开发新模型非常重要。
