Dosage framework and resilient behavior of waste foundry sand-cement mixtures

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics Pub Date : 2025-07-12 DOI:10.1016/j.trgeo.2025.101640

Marcelo Heidemann , Helena Paula Nierwinski , António Viana da Fonseca , Sara Rios

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引用次数: 0

Abstract

Waste foundry sands (WFS) are a byproduct of the foundry industry with potential applications in construction, but WFS are still frequently landfilled worldwide. This study investigates the use of Portland cement (PC) to enhance the resilient modulus (RM) of compacted WFS, as its pure state does not meet the stiffness requirements for pavement layers. To provide a dosage framework and demonstrate the suitability of Portland cement as a stabilizing agent, the effects of different cement contents (c_iv), porosities (η), and curing times on the unconfined compressive strength (UCS) and split tensile strength (STS) were evaluated through laboratory tests. Specimens were prepared under two distinct porosities, corresponding to normal and modified compaction energies, with five cement contents ranging from 3 % to 15 % and three curing periods (7, 14, and 28 days). The results indicate that UCS and STS are governed by the η/c_iv ratio, with their variation well described by a power function that also accounts for curing time. The STS/UCS ratio for WFS-PC mixtures is approximately 0.15. Cyclic triaxial tests revealed a significant RM increase due to PC addition, primarily controlled by the stress state but also consistently influenced by the η/c_iv ratio. A model based on confining and deviatoric stress was adapted to incorporate the influence of the η /c_iv ratio in RM predictions, in addition to the confining and deviator stresses. This revised model provides valuable insights for WFS-PC dosage, enabling the identification of multiple porosity and cement content combinations to achieve a target RM. Moreover, since UCS evolution over time can also be captured by a unified model based on η/c_iv, it is possible to predict long-term RM from UCS measurements at shorter curing times. Although such correlations are specific to this WFS, their extension to other WFS and natural materials can be easily performed following the framework proposed herein.

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废铸造砂-水泥混合料的掺量、结构及回弹性能

废铸造砂（WFS）是铸造工业的副产品，在建筑领域具有潜在的应用前景，但在世界范围内仍经常被填埋。由于纯态WFS不满足路面层刚度要求，本研究研究了使用波特兰水泥（PC）来提高压实后WFS的弹性模量（RM）。为了提供一个剂量框架并证明波特兰水泥作为稳定剂的适用性，通过实验室试验评估了不同水泥含量（civ）、孔隙率（η）和养护时间对无侧限抗压强度（UCS）和劈裂抗拉强度（STS）的影响。在两种不同的孔隙率下制备试样，对应于正常和改良的压实能，5种水泥含量从3%到15%，3个养护周期（7、14和28天）。结果表明，UCS和STS受η/civ比的影响，它们的变化可以用幂函数很好地描述，幂函数也可以解释固化时间。WFS-PC混合物的STS/UCS比约为0.15。循环三轴试验表明，PC的加入显著增加了RM，这主要受应力状态控制，但也受η/civ比的影响。采用基于围压和偏应力的模型，除考虑围压和偏应力外，还考虑了RM预测中η /civ比的影响。该修正模型为WFS-PC用量提供了有价值的见解，能够识别多种孔隙度和水泥含量组合，从而实现目标RM。此外，由于UCS随时间的变化也可以通过基于η/civ的统一模型来捕获，因此可以通过UCS测量在较短的固化时间内预测长期RM。虽然这种相关性是特定于这种WFS的，但根据本文提出的框架可以很容易地将其扩展到其他WFS和天然材料。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Transportation Geotechnics Social Sciences-Transportation

CiteScore

8.10

自引率

11.30%

发文量

194

审稿时长

51 days

期刊介绍： Transportation Geotechnics is a journal dedicated to publishing high-quality, theoretical, and applied papers that cover all facets of geotechnics for transportation infrastructure such as roads, highways, railways, underground railways, airfields, and waterways. The journal places a special emphasis on case studies that present original work relevant to the sustainable construction of transportation infrastructure. The scope of topics it addresses includes the geotechnical properties of geomaterials for sustainable and rational design and construction, the behavior of compacted and stabilized geomaterials, the use of geosynthetics and reinforcement in constructed layers and interlayers, ground improvement and slope stability for transportation infrastructures, compaction technology and management, maintenance technology, the impact of climate, embankments for highways and high-speed trains, transition zones, dredging, underwater geotechnics for infrastructure purposes, and the modeling of multi-layered structures and supporting ground under dynamic and repeated loads.