Study On The Properties Of Recycled Powder For Foam Concrete

The key to getting rid of the energy crisis lies in the rational use of resources,and the recycling of construction waste not only conforms to current environmental protection policies,but also effectively saves gravel resources.The use of recycled fine powder to prepare foam concrete can not only solve the problem of resource utilization of construction waste,but also solve the problem of poor fire resistance of organic thermal insulation materials.The recycled fine aggregate with a particle size of less than 4.75mm after crushing of the waste concrete is ground by a ball mill to prepare recycled fine powder.In this experiment,recycled micropowder was used to replace part of the cement to prepare foam concrete.The amount of recycled micropowder,hydrogen peroxide content,water-to-binder ratio,and the compressive strength,water absorption,and thermal conductivity of foamed concrete mixed with recycled micropowder and fly ash And the influence of microstructure.The main findings are as follows:(1)When the amount of hydrogen peroxide is 4%and 5%,the single-mixed amount of recycled fine powder increases,and the compressive strength of foam concrete decreases;When the amount of hydrogen peroxide is 6%,the compressive strength of foamed concrete increases first and then decreases with the increase of the amount of recycled fine powder.Under the condition of keeping the amount of recycled fine powder unchanged and controlling the same water-to-binder ratio,the compressive strength of foam concrete gradually decreases with the increase of the amount of hydrogen peroxide;Under the condition of keeping the amount of recycled fine powder unchanged and controlling the same amount of hydrogen peroxide,the compressive strength of foamed concrete increases first and then decreases with the increase of water-binder ratio,And when the water-binder ratio is 0.62,the compressive strength of foam concrete is better;When the water-binder ratio and the amount of hydrogen peroxide do not change,the compressive strength of the foam concrete mixed with fly ash and recycled fine powder is better than that of the foam concrete mixed with recycled fine powder alone.(2)When the amount of hydrogen peroxide is 4%,the thermal conductivity of foam concrete decreases with the increase of the amount of recycled fine powder alone;When the content of hydrogen peroxide is 6%,the single content of recycled fine powder has little effect on the thermal conductivity of foamed concrete;Under the condition of keeping the amount of recycled fine powder unchanged and controlling the same water-to-binder ratio,the thermal conductivity of foam concrete decreases with the increase of the amount of hydrogen peroxide.And when the amount of hydrogen peroxide is 6%,the thermal conductivity of foam concrete is the best;When the amount of recycled fine powder is kept constant and the amount of hydrogen peroxide is kept constant,the thermal conductivity of foam concrete decreases with the increase of water-to-binder ratio;When the water-binder ratio and the amount of hydrogen peroxide do not change,the mixed micro-powder and fly ash have little effect on the thermal conductivity of foamed concrete.(3)When the amount of hydrogen peroxide is 4%,the water absorption rate of foamed concrete increases with the increase of the amount of single-cycle recycled fine powder;When the amount of hydrogen peroxide is 6%,the amount of recycled micro-powder has little effect on the water absorption of foamed concrete;Keeping the amount of recycled fine powder unchanged and controlling the same water-to-binder ratio,the water absorption of foamed concrete increases with the increase of the amount of hydrogen peroxide,And when the amount of hydrogen peroxide is 6%,the foam concrete has the highest water absorption rate;When the amount of hydrogen peroxide is 6%,the combination of recycled fine powder and fly ash has little effect on the water absorption of foamed concrete;Keeping the amount of recycled fine powder unchanged and the amount of hydrogen peroxide unchanged,the water absorption of foamed concrete increases with the increase of water-to-binder ratio.(4)When the water-binder ratio is 0.62,the amount of hydrogen peroxide is 6%of the cementitious material,cement:fly ash:recycled fine powder=70:10:20,the prepared foam concrete meets the compressive strength greater than 0.3MPa and the thermal conductivity is only0.0858W/m·K.