Study on in-situ modification of poly-dopamine on glass fibers and its effect on shrinkage performance of cement materials

Abstract

Cement-based materials are one of the essential construction materials that had been widely used in infrastructure and facilities. However, it experienced shrinkage problems, which led to the cracking of concrete buildings and deterioration of the durability. The incorporation of glass fibers can improve the shrinkage resistance of cement materials by enhancing the interface between cement and fiber. Aiming at improving the shrinkage resistance of cement, in this study, glass fibers were in-situ modified with poly-dopamine in aqueous solution. The effect of dopamine hydrochloride concentration and the pH of the solution were investigated with the optimal condition attained to be 2×10−3 g/ml and 8.5, respectively. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy analysis (XPS) were utilized for the characterization of as-prepared poly-dopamine modified glass fibers. Subsequently, as-prepared and untreated glass fibers were mixed with cement at varied volume fraction and water-cement ratio for the study of shrinkage performance. The glass fiber-reinforced cement had a lower shrinkage than cement without glass fibers. Compared with the cement without glass fibers, when the water-cement ratio was 0.4 and the volume content of in-situ modified glass fibers of poly-dopamine was 7%, the reduction in 28-day shrinkage of poly-dopamine in-situ modified glass fiber-reinforced cement was large extent, reducing by 42%. The shrinkage resistance performance of in-situ modified glass fibers reinforced cement with poly-dopamine was better than that of untreated glass fibers. In short, this work developed novel approach for in-situ modification of glass fibers and found a new path to improve the shrinkage resistance of cement material.