Recognition of the free slump in dry concrete mix: A 3D-digital image correlation test and the spatiotemporal variability

Abstract

Dry concrete mix has advantages of high construction efficiency and rapid early strength development. It has been employed extensively in a variety of sectors, including construction and pavement engineering. Traditional methods assessing its workability such as the Vebe test are susceptible to human error, which usually leads to the lack of the satisfactory accuracy in practice. To address the limitations of traditional methods, this study develops a three-dimensional digital image correlation (3D-DIC) method to meticulously recognize the free slump in dry concrete mix. Owing to the prominent advances in high precision and full-field measurement, the 3D-DIC method enables a novel monitoring and visualization of the free slump in terms of the spatiotemporal variability, i.e., the temporal evolution and the spatial variability. It is meanwhile possible to elucidate the spatiotemporal variability through two statistical models such as the Gaussian model and the semi variogram exponential model. Consequently, the 3D-DIC method presents two synergistic parameters of high accuracy other than a single one of low accuracy as used in traditional methods to quantify the free slump in dry concrete mix, which correspond respectively to the consistency and cohesiveness of the workability.