Since curing remains an essential parameter that directly influences concrete strength and durability, this research aimed at evaluating the effects of water, sodium chloride (NaCl), and sodium carbonate (Na₂CO₃) curing regimes on concrete’s strength and durability. The design mix was composed of concrete mix ratio of 1:2:4, hydrated ordinary Portland cement with a water/binder ratio of 0.50, river sand as fine aggregates, and varying percentages of heat-processed waste PET plastics and granite as coarse aggregates. The curing regimes’ performance was assessed by performing tests viz.: split tensile strength, compressive strength, and water absorption tests. The results showed that the curing regimes slightly influenced the split tensile and compressive strength of PET-modified concrete. The 5%-NaCl and 5%-Na₂CO₃ cured samples, compared to the samples cured in water, gained improved compressive strength values at all curing ages. NaCl curing further led to improved split tensile strengths for the 10 and 20% PET mixes. However, the water cured 20%-PET sample achieved the highest split tensile strength among PET-modified mixes after 28 days. PET-modified concretes attained water absorption percentages within the acceptable limit for normal concrete under the three curing regimes. Statistically, significant correlations and variations were established between the mechanical and durability properties assessed. The study concluded that the NaCl curing technique offers satisfactory performance at 10 and 20% PET replacement levels.

Graphical abstract

中文翻译：

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不同固化体系对再生PET改性混凝土强度和耐久性的影响

由于养护仍然是直接影响混凝土强度和耐久性的重要参数，因此本研究旨在评估水，氯化钠（NaCl）和碳酸钠（Na ₂ CO ₃）关于混凝土强度和耐久性的养护制度。设计配合比由1：2：4的混凝土配合比，水灰比为0.50的水合普通硅酸盐水泥，细集料的河砂和不同比例的经热处理的废弃PET塑料和花岗岩的粗集料组成。通过进行以下测试来评估固化方案的性能，即：拉伸强度，压缩强度和吸水率测试。结果表明，养护方式对PET改性混凝土的劈裂抗拉强度和压缩强度有轻微的影响。5％-NaCl和5％-Na ₂ CO ₃与在水中固化的样品相比，固化样品在所有固化年龄下均获得了更高的抗压强度值。NaCl固化进一步提高了10％和20％PET混合物的劈裂抗张强度。但是，水固化的20％-PET样品在28天后达到了PET改性混合物中最高的劈裂抗张强度。在三种固化方式下，PET改性混凝土达到的吸水率在普通混凝土可接受的范围内。从统计学上讲，在评估的机械性能和耐久性之间建立了显着的相关性和变异性。研究得出的结论是，NaCl固化技术在10％和20％的PET替代水平下提供令人满意的性能。

图形概要