Recycled Clay Brick Micro-powder Activity Excitation And Its Application In Foamed Concrete

Aiming at the problem of low activity of recycled brick powder,this thesis studies the influence of physical and chemical excitation methods on the activation effect and mechanism of recycled clay brick powder activation,and further develops the application research of activated clay brick powder in foam concrete.Use calcium oxide,sodium hydroxide,and composite activator(Ca O:Na OH=4:1)to excite clay brick powder activated brick powder,and replace part of cement with activated clay brick powder as a cementing material to prepare recycled clay brick-cement-based cementing materials,study the effects of different activators on the mechanical properties(compressive strength),hydration products(XRD,TG-DTG)and hydration heat release characteristics(TAM-air)of recycled clay brick-cement-based cementitious materials.At the same time,the alkali-excited clay brick powder was mixed into the foam concrete,and the water-to-binder ratio,activated regenerated clay brick powder,rubber powder and hydrogen peroxide content on the compressive strength of the regenerated clay brick powder foam concrete were studied.The influence of dry density and thermal conductivity.The main research results are as follows:The results of the active stimulation test of clay brick powder show that when the content of alkali activator does not exceed 5%,both calcium oxide and composite alkali activator(Ca O+Na OH)can increase the 28d strength of the clay brick-cement-based cementitious material.When the content is 3%,the 28d strength of the calcium oxide base stimulated composite cementing material is 21.81MPa,and the 28d strength of the composite base activator stimulated composite cementing material is 22.42MPa.Compared with the unstimulated sample,the strength is increased by 29.59%and 33.21%.Sodium hydroxide can increase the28d strength of the clay brick-cement-based composite cementitious material,but when the sodium hydroxide content exceeds 1%,it will adversely affect the strength of the composite cementitious material,and the strength is lower than the non-alkali excitation test.When using alkali to activate the clay brick powder,the content of calcium oxide and composite alkali should not exceed 5%,and the content of sodium hydroxide should not exceed 1%.Studying the activation mechanism of alkali activator on clay brick powder,we know that the incorporation of construction waste brick powder and activator composite powder material will not change the hydration product composition of cement paste,but it will change the hydration product calcium hydroxide.The quantity,thereby improving the compactness and strength of the composite cementitious material.The experimental research results of foam concrete show that when the brick powder content increases,the compressive strength decreases,the dry density increases slightly,and the thermal conductivity increases.When the water-binder ratio and hydrogen peroxide increase,the compressive strength decreases,the dry density decreases,and the thermal conductivity decreases.When the amount of rubber powder increases,the compressive strength,dry density and thermal conductivity of the recycled brick powder foam concrete increase.When the brick powder content is 40%,the water-binder ratio is 0.5,the rubber powder content is 0.1%,and the hydrogen peroxide content is 8%,the dry density of the recycled brick powder foam concrete reaches 1122.3kg/m~3 and the compressive strength It is 3.76MPa and the thermal conductivity is 0.059134W/(m·K),which meets the requirements of JG/T266-2011"Foam Concrete"standard.