Evaluation of the Pore Characteristics and Microstructures of Concrete with Fly Ash, Limestone-Calcined Clay, Seawater, and Sea Sand

• Published in: Arabian journal for science and engineering (2011) 2022-10, Vol.47 (10), p.13603-13622
• Main Authors: Liu, Jun, Liu, Jiaying, Jin, Hesong, Fan, Xu, Jiang, Zhilu, Zhu, Jihua, Liu, Wei
• Format: Article
• Language: English
• Subjects: Clay; Concrete; Concrete structures; Densification; Engineering; Fly ash; Fractal geometry; Fractal models; Fractals; Gels; Humanities and Social Sciences; Limestone; Microstructure; multidisciplinary; Pore size; Pore size distribution; Porosity; Prediction models; Predictions; Regression analysis; Research Article-Civil Engineering; Roasting; Sand; Scanning electron microscopy; Science; Seawater; X-ray diffraction
• ISSN: 2193-567X; 1319-8025; 2191-4281
• DOI: 10.1007/s13369-022-06809-2

Due to the shortage of freshwater and river sand resources, the utilization of seawater and sea sand is likely to become an effective way to improve this situation. However, seawater and sea sand have a significant impact on the microstructures of concrete. According to previous studies, adding a certain amount of fly ash and limestone-calcined clay (LC 2 ) to concrete can densify the matrix. Therefore, this study explored the micromorphology, pore structures, and phase evolution of seawater and sea sand concrete (SSC) under different conditions through mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Additionally, the fractal prediction model of seawater sea sand concrete is established through data regression analysis. The results show that seawater and sea sand can optimize the pores of SSC. Similarly, fly ash and LC 2 improved the pore size distribution of SSC, significantly increasing the proportion of transition pores, up to 89.68%. However, the porosity increased by approximately 30%. According to the SEM and XRD results, the addition of seawater and sea sand enabled the formation of more C-S–H gels in the matrix and the densification of the concrete structure. In addition, the established fractal prediction model can estimate the fractal dimension of SSC, thereby predicting the pore size distribution. Overall, this work not only provides a theoretical basis for the microscopic pore structure of future international research on the microscopic properties of SSC but also explores the feasibility of seawater and sea sand application in practical engineering by adding fly ash and LC 2 .