Study On Physical Mechanics And Freezing Resistance Of Aluminum Ash-Fly Ash Non-autoclaved Aerated Concrete

This paper produced A7.5B08 aluminum-fly ash aerated concrete with secondary aluminum dust?a kind of waste in the aluminum industry?replacing aluminum powder and multiple maintenance way consisting of three-day 60?steam curing and seven-day natural curing replacing autoclaved curing.By exploring the influence of different factors on the pouring quality and main properties of alumina-fly ash aerated concrete,the basic materials and additives were determined in turn,and the optimum mixing ratio of alumina-fly ash aerated concrete with A7.5B08 specification was obtained as follows:fly ash 62.5%,cement 11.5%,quicklime 23.0%,gypsum 3.0%,secondary alumina lime 0.48%,twelve.Sodium alkyl sulfate 0.7%,sodium silicate 5.0%,anhydrous sodium sulfate 0.2%,triethanolamine 0.02%,water-to-material ratio 0.55;pouring temperature 40 C,static temperature 60 C.A7.5B08 aluminium ash-fly ash aerated concrete has 61.01%porosity,22.0%moisture content and 41.8%water absorption.The quality loss rate of the aerated concrete with aluminium ash and fly ash is similar to that of the autoclaved aerated concrete with the same specification after freeze-thaw,but the compressive strength of the autoclaved aerated concrete with the same specification after freeze-thaw is lower than that of the autoclaved aerated concrete with the same specification.The influence of dry-wet cycle on the aerated concrete with aluminium ash and fly ash is not obvious.Through the study of physical and durability of aerated concrete with aluminium ash and fly ash and SEM analysis,it is found that there are a certain number of connecting holes and Macroholes in the concrete.By XRD analysis,it is found that the hydrate is mainly composed of glass phase and gel,and less crystalline phase,which is an important reason for its low strength.Through XRD analysis of secondary aluminium ash,it is found that it contains impurities such as Al₂O₃ and AlN,which may affect the fuming of aluminium ash and also pollute the environment.