Abstract:The capillary water absorption of coal gangue concrete(CGC) and ordinary concrete(OC) was studied under the action of freeze thaw, and ASTM C1585 13 was introduced to measure the water absorption rate of hydraulic cement concrete. The effects of freeze thaw cycles and coal gangue replacement rate on the capillary water absorption of CGC were analyzed, and the prediction model of the initial water absorption rate of CGC under the action of freeze thaw was established. Results show that with the increase of the coal gangue replacement rate under the same freeze thaw environment, or with the increase of the freeze thaw cycles number under the same coal gangue replacement rate, the cumulative water absorption, the initial water absorption rate and the capillary water absorbing capacity will all increase respectively; the capillary water absorbing capacity of CGC is greater than OC; the CGC has a strong response to freeze thaw cycles. The predict model of the initial water absorption rate of CGC under the freeze thaw environment was established by regression analysis, which has a relatively high computation precision. The model can be used to predict the capillary water absorption properties of CGC, which provides theoretical support for the research on frost resistance of CGC.