镁渣基碳化养护加气混凝土的制备OA北大核心

Magnesium slag is an industrial by-product of magnesium production,which exhibits high carbonation activity due to the presence of large amount of dicalcium silicate in its composition.Here,a MS-based carbonated aerated concrete(MCAC)is reported.The mixture is mainly composed of MS powder,supplemented with a small amount of Portland cement with high hydration activity to provide demolding strength.The density of MCAC(750 kg/m3)is regulated by aluminum powder,and the effect of different carbonation systems on the mechanical prop-erties and void structure is studied.By controlling the water to solid ratio,carbonization time and pre-drying treat-ment time,the best carbonization system is explored.The results reveal that the water to solid ratio of 0.24 is de-termined to be the best;there is almost zero of the compressive strength of MCAC after 12 h standard pre-curing(before carbonation).After carbonation for 24 h at 0.1 MPa,the compressive strength of MCAC reaches 5.3 MPa.The moisture before carbonation of 16％is considered as the optimum value,which can be controlled by pre-dying treatment.In addition,a large amount of calcium carbonate with calcite and a small amount of aragonite as the main crystal is generated after carbonation,which gradually deposits on the void inner surface along with the carbonation.This study provides a new insight into the preparation of a new type of green and sustainable aer-ated concrete,accompanied by the achievement of CO2 solidification.