Producing Heavyweight High-Performance Concrete by Using Black Sand as Newly Shielding Construction Material

Area of Science:

• Materials Science
• Civil Engineering
• Nuclear Engineering

Background:

• Heavyweight high-performance concrete (HWHPC) is crucial for radiation shielding.
• Developing cost-effective and efficient shielding materials is an ongoing challenge.
• Black sand (BS) is a potential candidate for enhancing concrete properties.

Purpose of the Study:

• To evaluate the impact of black sand (BS) on the mechanical, durability, and shielding characteristics of HWHPC.
• To investigate the combined effects of fly ash (FA) and BS on HWHPC performance.
• To determine the optimal mixture proportions for improved HWHPC properties.

Main Methods:

• Fifteen HWHPC mixtures were prepared with varying percentages of FA (10%, 15%) and BS (15%–100%) replacing cement and sand, respectively.
• Specimens were tested after exposure to elevated temperatures (250 °C–750 °C), magnesium sulfate (MS), and gamma-ray radiation.
• Mechanical properties (compressive strength), durability (mass loss), and shielding characteristics (linear attenuation coefficient) were assessed.

Main Results:

• Black sand significantly improved concrete compressive strength, with 15% BS showing superior performance compared to control mixes.
• Elevated temperatures up to 250 °C increased compressive strength, while BS enhanced fire resistance, particularly at 750 °C.
• The combination of 10% FA and 15% BS yielded the most significant improvements in overall HWHPC properties, including shielding effectiveness.

Conclusions:

• Black sand is a viable and effective material for enhancing the shielding and mechanical properties of HWHPC.
• The optimal mixture of 10% fly ash and 15% black sand offers a synergistic effect, improving concrete performance across various conditions.
• This research provides valuable insights for developing advanced shielding concrete materials using sustainable aggregates.