Eltawil Khaled A, Mahdy Mohamed G, Youssf Osama, Tahwia Ahmed M
Department of Structural Engineering, Faculty of Engineering, Mansoura University, Mansoura 35511, Egypt.
Science, Technology, Engineering and Mathematics Unit, University of South Australia, Adelaide, SA 5095, Australia.
Materials (Basel). 2021 Sep 16;14(18):5353. doi: 10.3390/ma14185353.
Experimental work was carried out to study new fine aggregate shielding construction materials, namely black sand (BS). The BS effect on the mechanical, durability, and shielding characteristics of heavyweight high-performance concrete (HWHPC) was evaluated. This study aimed at improving various HWHPC properties, concertedly. Fifteen mixtures of HWHPC were made, with various variables, including replacing 10% and 15% of the cement with fly ash (FA) and replacing normal sand by BS at various contents (15%, 30%, 45%, 60%, 75%, and 100%). The test specimens were subjected to various exposure conditions, including elevated temperatures, which ranged from 250 °C to 750 °C, for a duration of 3 h; magnesium sulfate (MS) exposure; and gamma-ray exposure. The effects of elevated temperature and sulfate resistance on concrete mass loss were examined. The results revealed that BS is a promising shielding construction material. The BS content is the most important factor influencing concrete compressive strength. Mixes containing 15% BS demonstrated significantly better strength compared to the control mixes. Exposure to 250 °C led to a notable increase in compressive strength. BS showed a significant effect on HWHPC fire resistance properties, especially at 750 °C and a significant linear attenuation coefficient. Using 10% FA with 15% BS was the most effective mixing proportion for improving all HWHPC properties concertedly, especially at greater ages.
开展了实验工作以研究新型细集料屏蔽建筑材料，即黑砂（BS）。评估了黑砂对重质高性能混凝土（HWHPC）的力学、耐久性和屏蔽特性的影响。本研究旨在协同改善重质高性能混凝土的各种性能。制备了15种重质高性能混凝土混合物，包含各种变量，其中包括用粉煤灰（FA）替代10%和15%的水泥，并用不同含量（15%、30%、45%、60%、75%和100%）的黑砂替代普通砂。对测试样本进行了各种暴露条件测试，包括在250℃至750℃范围内的高温下持续3小时；硫酸镁（MS）暴露；以及伽马射线暴露。研究了高温和抗硫酸盐性对混凝土质量损失的影响。结果表明，黑砂是一种很有前景的屏蔽建筑材料。黑砂含量是影响混凝土抗压强度的最重要因素。与对照混合物相比，含15%黑砂的混合物表现出显著更好的强度。暴露在250℃下会导致抗压强度显著增加。黑砂对重质高性能混凝土的耐火性能有显著影响，尤其是在750℃时，且具有显著的线性衰减系数。使用10%的粉煤灰与15%的黑砂是协同改善所有重质高性能混凝土性能的最有效混合比例，尤其是在更长龄期时。
