Zaid Osama, Althoey Fadi, García Rebeca Martínez, de Prado-Gil Jesús, Alsulamy Saleh, Abuhussain Mohammed Awad
Department of Civil Engineering, Swedish College of Engineering and Technology, 47070, Wah Cantt, Punjab, Pakistan.
Department of Civil Engineering, College of Engineering, Najran University, Najran, Saudi Arabia.
Heliyon. 2023 Sep 9;9(9):e19978. doi: 10.1016/j.heliyon.2023.e19978. eCollection 2023 Sep.
Recycled aggregate (RA) made from waste concrete is an environmentally friendly alternative to natural aggregate (NA) for concrete manufacturing. However, compared to NA concrete, concrete produced with recycled aggregates has poor characteristics. Supplementary cementitious materials (SCMs) can be used to enhance the poor properties of recycled aggregate concrete (RAC). Silica fume and fly ash are commonly used SCMs in the World, but their high usage led to a shortage of silica fume and fly ash. Still, the deficiency of these materials in large parts of the world is a challenge that requires exploring alternative feedstock materials for the construction industry in the coming years. Wheat straw ash (WSA) is an agricultural waste product that could be used as an alternative SCM due to its pozzolanic behavior to enhance the properties of RAC. In addition, concrete is brittle and needs reinforcement, for which polypropylene fibers (PPFs) can be used. The current research examines the mechanical characteristics of fiber-reinforced RAC, including compressive strength, splitting tensile strength, and ductility performance. Durability indicators, such as chloride diffusion, chloride penetration, acid resistance, and water absorption test, were also assessed. The results showed that concrete samples with 10% WSA, 50% RA and 1.5% PPFs had the highest compressive and splitting tensile strength, 60.2 MPa and 7.25 MPa, respectively, representing increases of 24.75% and 30.65%, as compared to plain samples at 56 days. In these samples, water absorption was reduced by 13% due to the finer WSA particles resulting in the lowest reduction in strength and mass recorded when exposing concrete samples to acidic media. The statistical analysis also validated that irrespective of WSA and PPFs, the concrete with 0% RA had the highest performance in strength and durability behavior. The study showed that WSA and PPFs might be employed in tandem to offset the poor behavior of RA, enhance the bond between fibers and concrete, and improve the mechanical strength and durability performance of RAC, thus demonstrating its suitability as a sustainable and economical construction material.
由废弃混凝土制成的再生骨料（RA）是混凝土生产中天然骨料（NA）的一种环保替代品。然而，与天然骨料混凝土相比，用再生骨料生产的混凝土性能较差。辅助胶凝材料（SCMs）可用于改善再生骨料混凝土（RAC）的不良性能。硅灰和粉煤灰是世界上常用的辅助胶凝材料，但它们的大量使用导致了硅灰和粉煤灰的短缺。尽管如此，在世界大部分地区这些材料的短缺仍是一个挑战，需要在未来几年为建筑业探索替代原料。麦秸灰（WSA）是一种农业废弃物，由于其火山灰特性，可作为替代辅助胶凝材料来改善再生骨料混凝土的性能。此外，混凝土是脆性的，需要增强，对此可使用聚丙烯纤维（PPF）。当前的研究考察了纤维增强再生骨料混凝土的力学特性，包括抗压强度、劈裂抗拉强度和延性性能。还评估了耐久性指标，如氯离子扩散、氯离子渗透、耐酸性和吸水性试验。结果表明，含有10%麦秸灰、50%再生骨料和1.5%聚丙烯纤维的混凝土样品具有最高的抗压强度和劈裂抗拉强度，分别为60.2MPa和7.25MPa，与56天时的素混凝土样品相比，分别提高了24.75%和30.65%。在这些样品中，由于麦秸灰颗粒更细，吸水性降低了13%，在将混凝土样品暴露于酸性介质时，强度和质量的降低幅度最小。统计分析还证实，无论有无麦秸灰和聚丙烯纤维，不含再生骨料的混凝土在强度和耐久性方面表现最佳。研究表明，麦秸灰和聚丙烯纤维可协同使用，以弥补再生骨料的不良性能，增强纤维与混凝土之间的粘结力，并改善再生骨料混凝土的机械强度和耐久性，从而证明其作为一种可持续且经济的建筑材料的适用性。
