Enhancing the microscopic structure of seawater sea-sand concrete through compression casting technique

Abstract

The global demand for concrete production drives the search for suitable raw materials. This study investigates the potential for enhancing the performance of seawater sea-sand concrete through compression casting, addressing a gap in the existing literature. The study involved the preparation of compressed seawater sea-sand concrete specimens using three different compression pressures (5, 10, and 15 MPa) and two compression durations (8 and 1440 min). These specimens were then compared with uncompressed ones, including desalted sand tap water concrete and conventional seawater sea-sand concrete. The results indicate that an increase in compression pressure significantly improves the mechanical performance and reduces porosity in the concrete specimens. However, applying pressure for an extended duration does not yield a significant improvement, making it less practical due to production efficiency considerations. Thermogravimetric, differential thermogravimetric, scanning electron microscopy and energy-dispersive spectroscopy analyses revealed no substantial impact on the hydration of seawater sea-sand concrete due to compression pressure. Mercury intrusion porosimetry and backscattered electron imaging showed that the compression casting technique is particularly effective in improving the structure of the interfacial transition zone for pore diameters larger than 50 nm, leading to enhanced mechanical performance in seawater sea-sand concrete. These findings have practical implications for the use of seawater sea-sand concrete, addressing concerns related to the scarcity of specific natural resources, scarcity of raw materials, and performance issues. Ultimately, this research contributes to the efficient management and utilization of natural resources in concrete production, offering a sustainable approach to meet the global demand for concrete manufacturing.