气凝胶和碱激发粉煤灰对发泡混凝土的影响

The Influence of Aerogel and Alkali Activated Fly Ash on Foamed Concrete

分别探讨了粉煤灰、气凝胶和CaO对双氧水发泡混凝土结构和性能的影响。研究表明,气凝胶可以提高发泡速率和发泡体积,当发泡时间增至200s后,发泡速率降低至0.1mm/s,发泡过程基本停止。随着气凝胶掺量的增大,导热系数和抗压强度随之下降。但泡沫混凝土孔隙率增大,吸水率随着上升。气凝胶掺量增大时易附着在泡孔壁上,使孔壁防水性能提高,软化系数增大。固定气凝胶掺量为1%,当CaO掺量为0.3%,粉煤灰取代量为40%时,双氧水分解率提高,粉煤灰活性被激发,粉煤灰和水泥水化产物相互搭接在孔壁上形成网状结构,导热系数为0.052 W/(m·K),抗压强度为0.72MPa。CaO激发活性的粉煤灰可以有效降低气凝胶泡沫混凝土的容重和导热系数,降幅分别达17.6%和25.9%。

The effects of fly ash,aerogel,and CaO on the structure and performance of hydrogen peroxide foamed concrete were discussed separately.The experimental results show that aerogel can increase the foaming rate and foaming volume.When the foaming time increases to 200 s,the foaming rate reduces to 0.1 mm/s,and the foaming process basically stops.As the amount of aerogel increases,the thermal conductivity and compressive strength decrease.However,the porosity of foamed concrete increases,and the water absorption increases.When the aerogel content increases,it is easy to adhere to the cell wall,which improves the waterproof performance of the cell wall and increases the softening coefficient.The fixed aerogel content is 1%.When the content of CaO is 0.3%and the replacement content of fly ash is 40%,the decomposition rate of hydrogen peroxide will increase,the activity of fly ash will be activated,and the products of fly ash and cement hydration will interact with each other.It is connected to the hole wall to form a network structure,the thermal conductivity is 0.052 W/(m·K),and the compressive strength is 0.72 MPa.CaO activated fly ash can effectively reduce the bulk density and thermal conductivity of aerogel foam concrete by 17.6%and 25.9%,respectively.