Effect of MgO expansive agent on the shrinkage and mechanical properties of SHCC containing coarse silica sand

Strain hardening cementitious composites (SHCC) exhibit promising potential for pavement applications owing to their excellent crack control and self-healing ability. However, the high cement content and absence of coarse aggregates in SHCC lead to high shrinkage and poor wear resistance, limiting SHCC’s large-scale application. This study aims to develop a low-shrinkage SHCC containing coarse silica sand by incorporating MgO expansive agent (MEA), and compare its performance with SHCC incorporating shrinkage reducing agent (SRA). The effects of MEA and SRA with different contents on the shrinkage and mechanical properties of SHCC containing coarse silica sand were systematically investigated through shrinkage tests, abrasion tests, compression tests and tension tests. The results show that the incorporation of MEA and SRA both significantly reduces the shrinkage of SHCC, but the latter leads to a significant decrease in the mechanical properties of SHCC. The mechanism underlying the reduction of shrinkage by MEA and SRA, as well as their influence on mechanical properties, are investigated at the microscopic level through XRD and SEM analysis. Overall, this study provides valuable insights into the advantages of incorporating MEA in enhancing the properties of SHCC, thereby offering significant potential for practical pavement applications utilizing SHCC.