Banyai Kitti, Czoboly Oliver, Menyhart Krisztian, Orban Zoltan
University of Pecs, Faculty of Engineering and Information Technology, Structural Diagnostics and Analyses Research Team, H-7624 Pécs, Hungary.
Beton Technológia Centrum Ltd., H-1107 Budapest, Hungary.
Materials (Basel). 2025 Feb 28;18(5):1108. doi: 10.3390/ma18051108.
The principles of the circular economy and the effective utilization of construction and demolition waste are becoming increasingly important, as evidenced by a growing body of research in this field. However, studies focusing on the waterproofing properties and setting times of recycled concrete derived from various construction and demolition waste sources remain scarce. This research investigates the characteristics of recycled aggregates from different origins and explores how these characteristics influence the properties of concrete. The study examines the effects of pre-soaking aggregates to saturation, the incorporation of water absorption-reducing additives, and the ratio of recycled aggregates to natural aggregates on the properties of both fresh and hardened concrete. Laboratory tests were conducted on crushed recycled concrete aggregates (RCA), confirming that concrete produced with recycled aggregates can meet standard requirements for compressive strength and water resistance exposure classes despite the recycled aggregates themselves not meeting the required standards. The results were used to calculate an effective water-cement ratio and establish a correlation between this ratio and compressive strength. The findings indicated that the compressive strength of mixtures approached, and in most instances exceeded, that of the reference concrete utilizing natural aggregates. Specifically, the reference concrete (REF-1) achieved a compressive strength value of 51.4 MPa after 28 days, whereas the 30% recycled mixture (REC-10), made from pure concrete demolition waste, produced a compressive strength of 62.7 MPa. The maximum water penetration depth of the REC-10 mixture was measured at 11 mm, in comparison to 15 mm for the reference mixture (REF-1). Additionally, the initial setting time of the mixtures incorporating special additives reached the 80 min threshold. The practical aspects of this research examined potential industrial applications that do not necessitate special aggregate treatments, thus maintaining the water-cement ratio within acceptable limits. This study evaluates the feasibility of utilizing recycled concrete aggregates (RCA) from construction waste to produce concrete that satisfies the standard requirements for compressive strength and water resistance. It assesses the impact of RCA on performance, provides industrial insights, and suggests potential regulatory revisions.
循环经济原则以及建筑与拆除废物的有效利用正变得愈发重要，该领域越来越多的研究证明了这一点。然而，针对源自各种建筑与拆除废物源的再生混凝土的防水性能和凝结时间的研究仍然匮乏。本研究调查了不同来源再生骨料的特性，并探究这些特性如何影响混凝土的性能。该研究考察了将骨料预浸泡至饱和、掺入吸水性降低添加剂以及再生骨料与天然骨料的比例对新拌混凝土和硬化混凝土性能的影响。对破碎的再生混凝土骨料（RCA）进行了实验室测试，证实尽管再生骨料本身不符合要求标准，但用其生产的混凝土仍能满足抗压强度和耐水暴露等级的标准要求。利用测试结果计算了有效水灰比，并建立了该比值与抗压强度之间的相关性。研究结果表明，混合物的抗压强度接近并在大多数情况下超过了使用天然骨料的基准混凝土。具体而言，基准混凝土（REF - 1）在28天后达到了51.4 MPa的抗压强度值，而由纯混凝土拆除废物制成的30%再生混合物（REC - 10）的抗压强度为62.7 MPa。REC - 10混合物的最大水渗透深度测得为11 mm，而基准混合物（REF - 1）为15 mm。此外，掺入特殊添加剂的混合物的初凝时间达到了80分钟的阈值。本研究的实际方面考察了无需特殊骨料处理的潜在工业应用，从而将水灰比维持在可接受的范围内。本研究评估了利用建筑废物中的再生混凝土骨料（RCA）生产满足抗压强度和耐水标准要求的混凝土的可行性。它评估了RCA对性能的影响，提供了行业见解，并提出了潜在的监管修订建议。
