Identification of indexes that could reflect early drying shrinkage of high strength concrete with minerals

High-strength concrete (HSC) suffers severe shrinkage, which deteriorates the structural safety of buildings over time. Therefore, this study aims to search for indexes that could reflect the development of early drying shrinkage in HSC with different types/quantities of minerals. The influences of minerals on the internal pore structure and water evaporation of HSC were investigated by experimental work, whose correlation with early drying shrinkage was clarified. The results indicated that pore size distribution (PSD) and water evaporation of HSC should be taken into account simultaneously, facilitating the proposal of a two-factor parameter, rs, and a smaller rs was accompanied by greater drying shrinkage of samples. In addition, only partial mesopore lost water that led to drying shrinkage of HSC instead of water in all mesopores. Finally, an early drying shrinkage model of HSC based on rs was established correspondingly, which was in line with the experimental data, showing great accuracy, suitability and values in practice in reflecting early drying shrinkage behaviors of the HSC selected in this study. However, the current model is based on pore structure parameters obtained from mercury intrusion porosimetry (MIP). The backscattered electron image analysis (BSE-IA) measurement of pore structure indicates that MIP underestimates the content of pores larger than 200 nm. Therefore, the actual parameter rs should be greater than the currently calculated value. In the future, with the development of pore structure testing techniques, a more accurate rs value that closely represents the true value should be obtained, and a more universal model that considers several factors should be established. •Influences of different types/quantities of minerals on HSC were studied.•Correlation between pore structures and water evaporation of HSC were investigated.•The pore structure of HSC was investigated using both MIP and BSE-IA.•A two-factor parameter, rs in HSC was proposed to characterize shrinkage of HSC.•The early drying shrinkage model of HSC based on rs fitted well with the test results.