The increasing amount of tires manufactured annually worldwide has made waste tire management a major environmental concern. The goal of this work is to investigate the potential applications of waste tire aggregates (WTA) in a novel class of affordable, recycled composite materials. This study assesses the material behavior of rubberized 3D printed lightweight cement composites (3DLC) reinforced with raw micro attapulgite (ATP) and micro steel fibers (MSF) using WTA as a 100 % replacement for fine aggregate manufactured through 3D printing. The paper takes advantage of 3D concrete printing's advantages and addresses the environmental issues associated with waste tires. The extrudability and buildability properties of 3DLC are determined in the fresh state. Physical and thermal properties of 3DLC were determined. Mechanical properties of 3DLC including compressive, flexural, shear strength and flexural toughness were assessed. 3D printed samples were exposed to high temperature and sulfate (MgSO), and their durability properties were determined. The microstructures of the mixes was analyzed. The CO emissions and costs of the blends were also assessed. The outcomes revealed that, the 3DLC mixture with 10 % ATP and 2 % MSF showed the greatest compressive strength performance, with increases of 17.82 and 29.51 % at 28 and 90 days, respectively relative to the mixture without ATP. Regardless of MSF level, at 28 and 90 days, all mixes with 10%ATP content showed the largest flexural strengths. The 3DLC mixture with 10 % ATP and 2 % MSF had the highest measured thermal conductivity. The blends with 20 % ATP and 0 % MSF showed the lowest thermal conductivity. The mixture containing 10 % ATP and 2 % MSF demonstrated the greatest high temperature performance, demonstrating strength enhancement of 21.85, 6.72 and 3.36 % at 200,400 and 600°C respectively. Replacing cement with 10 and 20%ATP greatly increased the sulfate resistance of 3DLC mixtures and the mixture with 20%ATP and 2%MSF exhibited the best sulfate performance. The lowest CO2 emission and cost were determined for the mixture containing 20%ATP and 0%MSF (A20S0).

中文翻译：

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用微凹凸棒石和微钢纤维增强的绿色橡胶3D打印轻质水泥复合材料的耐久性：适印性和环境角度


全球每年生产的轮胎数量不断增加，使得废旧轮胎管理成为主要的环境问题。这项工作的目标是研究废旧轮胎骨料 (WTA) 在新型经济实惠的可回收复合材料中的潜在应用。本研究评估了用原始微凹凸棒土 (ATP) 和微钢纤维 (MSF) 增强的橡胶 3D 打印轻质水泥复合材料 (3DLC) 的材料行为，使用 WTA 作为通过 3D 打印制造的细骨料 100% 的替代品。该论文利用了 3D 混凝土打印的优势，解决了与废旧轮胎相关的环境问题。 3DLC 的可挤出性和可成型性特性是在新鲜状态下测定的。测定了 3DLC 的物理和热性能。评估了 3DLC 的机械性能，包括压缩强度、弯曲强度、剪切强度和弯曲韧性。将 3D 打印的样品暴露在高温和硫酸盐 (MgSO) 中，并测定其耐久性能。分析了混合物的微观结构。还评估了混合物的二氧化碳排放量和成本。结果显示，含有 10% ATP 和 2% MSF 的 3DLC 混合物表现出最大的抗压强度性能，相对于不含 ATP 的混合物，在 28 天和 90 天分别增加了 17.82 % 和 29.51%。无论 MSF 水平如何，在 28 和 90 天时，所有 ATP 含量为 10% 的混合物都显示出最大的弯曲强度。含有 10% ATP 和 2% MSF 的 3DLC 混合物具有最高的测量热导率。含有 20% ATP 和 0% MSF 的混合物表现出最低的导热率。 含有 10% ATP 和 2% MSF 的混合物表现出最佳的高温性能，在 200,400°C 和 600°C 下强度分别提高了 21.85%、6.72% 和 3.36%。用10%和20%ATP代替水泥大大提高了3DLC混合物的抗硫酸盐性能，其中20%ATP和2%MSF的混合物表现出最好的硫酸盐性能。确定含有 20% ATP 和 0% MSF (A20S0) 的混合物的 CO2 排放量和成本最低。