Synergistic effect of metakaolin and silica fume on hydrochloric acid resistance of concrete

Abstract

The issue caused by acid corrosion of concrete merits continued scientific attention. In this paper, the acid resistance of concrete incorporated different dosages of metakaolin (5 and 10% by weight of total cementitious materials) and silica fume (5, 10, and 15% by weight of total cementitious materials) was studied. Herein, special attention was paid to compressive strength, mass loss, dynamic elastic modulus, thickness of damage layer, and stress-strain response (including ductility and energy dissipation capacity). In addition, the stress-strain behavior was described by the damage constitutive model with the initial damage based on Weibull theory. Moreover, the morphology and characteristic of microstructure and erosion products formed in the specimen during the process of hydrochloric acid attack were studied via X-ray diffraction (XRD), thermo-gravimetric (TG) analysis, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The result revealed that the acid resistance of concrete was improved by the synergistic effect of MK and SF, in which the effect was notable when the dosage of both is 5%. The result of the study is of practical significance in improving the acid resistance of concrete.