Abbas Safeer, Ahmed Ali, Waheed Ayesha, Abbass Wasim, Yousaf Muhammad, Shaukat Sbahat, Alabduljabbar Hisham, Awad Youssef Ahmed
Department of Civil Engineering, University of Engineering and Technology, Lahore 54890, Pakistan.
Punjab Intermediate Cities Improvement Investment Program, Lahore 54660, Pakistan.
Materials (Basel). 2022 May 17;15(10):3584. doi: 10.3390/ma15103584.
Recycled rubber waste (RW) is produced at an alarming rate due to the deposition of 1.5 billion scrap tires annually around the globe, which causes serious threats to the environment due to its open land filling issues. This study investigates the potential application of RW in concrete structures for mitigating the alkali-silica reaction (ASR). Various proportions of RW (5%, 10%, 15%, 20%, and 25%) partially replaced the used aggregates. RW was procured from a local rubber recycling unit. Cubes, prisms, and mortar bar specimens were prepared using a mixture design recommended by ASTM C1260 and tested for evaluating the compressive and flexural strengths and expansion in an ASR conducive environment for specimens incorporating RW. It was observed that the compressive and flexural strength decreased for specimens incorporating RW compared to that of the control specimens without RW. For example, an 18% and an 8% decrease in compressive and flexural strengths, respectively, were observed for specimens with 5% of RW by aggregates volume at 28 days. Mortar bar specimens without RW showed an expansion of 0.23% and 0.28% at 14 and 28 days, respectively, indicating the potential ASR reactivity in accordance with ASTM C1260. A decrease in expansion was observed for mixtures incorporating RW. Specimens incorporating 20% of RW by aggregate volume showed expansions of 0.17% at 28 days, within the limit specified by ASTM C1260. Moreover, specimens incorporating RW showed a lower reduction in compressive and flexural strengths under an ASR conducive environment compared to that of the control specimen without RW. Micro-structural analysis also showed significant micro-cracking for specimens without RW due to ASR. However, no surface cracks were observed for specimens incorporating RW. It can be argued that the use of RW in the construction industry assists in reducing the landfill depositing issues with the additional benefit of limiting the ASR expansion.
由于全球每年有15亿条废旧轮胎被丢弃，再生橡胶废料（RW）的产生速度惊人，因其露天填埋问题对环境造成了严重威胁。本研究调查了RW在混凝土结构中减轻碱-硅反应（ASR）的潜在应用。用不同比例（5%、10%、15%、20%和25%）的RW部分替代用过的骨料。RW购自当地的橡胶回收单位。根据ASTM C1260推荐的配合比设计制备立方体、棱柱体和砂浆棒试件，并在有利于ASR的环境中对含有RW的试件进行抗压强度、抗折强度和膨胀测试。结果表明，与不含RW的对照试件相比，含有RW的试件的抗压强度和抗折强度有所降低。例如，在28天时，骨料体积含5% RW的试件的抗压强度和抗折强度分别降低了18%和8%。不含RW的砂浆棒试件在14天和28天时的膨胀率分别为0.23%和0.28%，表明根据ASTM C1260其具有潜在的ASR反应性。含RW的混合物的膨胀率有所降低。骨料体积含20% RW的试件在28天时的膨胀率为0.17%，在ASTM C1260规定的限值范围内。此外，与不含RW的对照试件相比，含RW的试件在有利于ASR的环境下抗压强度和抗折强度的降低幅度较小。微观结构分析还表明，不含RW的试件由于ASR出现了明显的微裂纹。然而，含RW的试件未观察到表面裂纹。可以认为，在建筑行业中使用RW有助于减少垃圾填埋问题，并具有限制ASR膨胀的额外好处。
