Discussion on the water absorption depth of gangue-based concrete and its relationship with the damage layer thickness

Abstract

Capillary water absorption is one of the key factors in evaluating the durability of concrete structures. In this paper, solid waste-coal gangue was used as raw material, and activated gangue powder (ACGP) was used to prepare gangue-based concrete (GBC) by partially replacing cement. The capillary water absorption performance of GBC under the action of freeze-thaw cycles was investigated by freeze-thaw cycle test as well as capillary water absorption test. The relationship between water absorption depth and water content was established. The interrelationship between the water absorption depth and the damage layer thickness was analyzed. The test results indicated that the frost resistance of concrete was enhanced after incorporating ACGP. The capillary water absorption performance of GBC was weaker than that of ordinary concrete, with less water content and lower sorptivity, and the effect was most apparent when the dosage of ACGP was 20%. The water absorption depth gradually grew with the number of freeze-thaw cycles and the water absorption time. There was a significant linear correlation between the water content and the water absorption depth, which provided a new insight into the prediction of the hardly measurable water absorption depth from the easily accessible water content. The water absorption depth was significantly higher than the damage layer thickness, and the difference between them was broadened after the incorporation of ACGP. Besides, an approximate linear relationship between the water absorption depth and the damage layer thickness was pointed out.