Study On The Adaptability Of Chemical Foaming Agent In Alkali Slag Cementitious Material System

With the increasingly prominent issues of environmental protection and energy,people have higher requirements for building materials.As a light-weight thermal insulation and fireproof building material,foamed concrete is particularly necessary to promote its greening and energy saving.Alkali slag foamed concrete is a new type of building material that came into being.Foamed concrete is mainly divided into two categories according to the different sources of bubbles in the paste: physical foaming method and chemical foaming method.At present,the alkali slag foamed concrete is basically foamed by the physical foaming method,but the quality of the physical foaming agent product is uneven,the economy is not good,and it is incapable of preparing low-density foamed concrete.Therefore,this paper uses chemical foaming agents(hydrogen peroxide and aluminum powder)to prepare alkali slag foamed concrete for related research.By measuring the gas production rate of chemical foaming agents(hydrogen peroxide and aluminum powder)in the simulated liquid to study their gas production behavior characteristics in different alkaline environments,and then compare the relevant formulation parameters for ordinary Portland cement and alkali slag The influence of the rheological properties of the slurry is to explore the relationship between the rheological properties of the alkali slag slurry and the foaming effect.Single factor experiments were used to study the influence of different components on the properties of alkali slag foamed concrete such as dry bulk density,compressive strength,mass water absorption,and average pore size.Orthogonal experiments were designed to analyze the degree of influence of each component on the basic properties such as foaming volume,dry bulk density,compressive strength,mass water absorption,and average pore size of the alkali slag foamed concrete,and to compare the alkali slag foaming agent system The characteristics of the factors affecting the performance of slag foamed concrete,and the optimal level is determined to provide the optimal mix ratio for the preparation of alkali slag foamed concrete.Experimental results show:(1)Increasing the temperature of the simulated liquid can increase the gas production rate of hydrogen peroxide and aluminum powder in the alkaline slag simulated liquid,and the change of temperature has a greater influence on the gas production rate of hydrogen peroxide in the simulated liquid than aluminum powder.(2)The plastic viscosity of alkali slag slurry decreases with the increase of water-cement ratio,and increases with the increase of water glass modulus and alkali equivalent;when the activator is Na OH,the plastic viscosity of alkali slag slurry is compared with the activator In the case of water glass,the plastic viscosity of alkali slag slurry is much larger;the foaming volume of alkali slag is more sensitive in the plastic viscosity range of 0.1-0.3Pa·s,and its size may be more easily affected by other factors.(3)When the chemical foaming agent is hydrogen peroxide and aluminum powder,water-cement ratio,sodium silicate modulus,alkali equivalent,tea saponin content on the dry bulk density,compressive strength,mass water absorption,average pore size of alkali slag foam concrete The influence of basic performance is not the same.Regardless of whether the chemical blowing agent is hydrogen peroxide or aluminum powder,the increase in modulus can increase the strength of the system,but there is an optimal value.Tea saponin and calcium stearate are compounded as foam stabilizers to reduce the dry bulk density.(4)According to the results of orthogonal test analysis,it can be seen that the alkali equivalent has a great influence on the performance of alkali slag foamed concrete.Combined with the actual workability of alkali slag foaming,it is determined that when the chemical foaming agent is hydrogen peroxide,the alkali slag foamed concrete The standard mixing ratio is: water-to-glue ratio 0.5,water glass modulus 1.2,alkali equivalent 6%,hydrogen peroxide content 9%,calcium stearate content 0.6%.When the chemical foaming agent is aluminum powder,the basic mixing ratio of alkali slag foamed concrete is: water-to-binder ratio 0.55,water glass modulus 1.2,alkali equivalent 8%,aluminum powder content 2.2%,calcium stearate content 0.6 %.(5)On the whole,the dry bulk density and compressive strength of alkali slag foamed concrete prepared with aluminum powder as a foaming agent are much smaller than those prepared with hydrogen peroxide.The dry bulk density of the alkali slag foamed concrete prepared with hydrogen peroxide is basically above 650 kg/m3,and it is impossible to prepare low-density alkali slag foamed concrete,while aluminum powder can prepare low-density alkali slag foamed concrete less than 300kg/m3 With the support of the project,the research content of this paper needs to meet the requirement of dry bulk density below 300kg/m3,so aluminum powder is more suitable as a foaming agent.