الفهرس 
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Abstract
The present study aims to develop a new heavy weight concrete type called heavyweight high-performance concrete (HWHPC). It’s characterized by resisting various nuclear radiation and an elevated temperature simultaneously over its operation time rely on using the appropriate proportion of multiple minerals from different used materials such as black sand (BS) and supplementary cementing materials (SCMs). Using various minerals aimed to balance between all HWHPC properties, not only the shielding properties. The BS is a promising concrete shielding material rich in specific minerals, and these minerals get sand with very special merit. It improves concrete properties, particularly at high temperatures, if used carefully. Many considerations should be taken to study the influence of BS on shielding attenuation properties, such as the water binder (W/B) ratio. SCMs such as FA and SF are used to enhance HWHPC performance. A total of 29 HWHPC mixes were made, with various variables, including replacing 10% and 15% of the cement with fly ash (FA) and replacing normal sand (NS) by BS at different contents (15%, 30%, 45%, 60%, 75%, and 100%). The test specimens were subjected to various exposure conditions, including elevated temperatures, which ranged from 250C to 750C, for a duration of 3h; magnesium sulfate (MS) exposure; and gamma-ray exposure. The effects of elevated temperature and MS 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. The preferred SCMs with BS is FA. The use of BS at rates ranging between 15% to 60% affected different properties of concrete are well maintained. Mixes containing 15% BS demonstrated significantly better strength compared to the control mixes. Exposure to 250C led to a notable increase in compressive strength. BS greatly affected HWHPC fire resistance properties, especially at 750C 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 later ages. Finally, the results indicated the possibility of using BS as a construction material in structures exposed to high temperatures and radiation shielding, especially gamma radiation. The significant HWHPC properties enhanced, especially strength through various exposure temperatures at 750C due to the formation of Friedel’s Salt (FS) due to different minerals such as Fe and Ti from BS, and Ca, Cl, and Al from FA with a suitable ratio.