Effect Of Polyvinyl Alcohol Fiber And Vitrified Microbead On Properties Of Foam Concrete

With the rapid development of green buildings and prefabricated buildings in China,foam concrete has been widely used in engineering due to its advantages such as light weight and high strength,thermal insulation,and environmental protection.However,in the engineering application of foam concrete,there are still problems such as foam instability,high bulk density,low strength,high water absorption,high thermal conductivity,and severe drying shrinkage.This essay studies the above issues and draws corresponding results which are as follows:Firstly,the foaming factor of the foaming liquid,the foam bulk density,the 1h water bleeding rate and the 1h settlement distance of the foam were studied through the type of foaming agent,the compression frequency of the foaming machine and the dilution factor of the foaming agent.Finally,the composite foam is selected and the compression frequency of the foaming machine is in 60 Hz,and the dilution factor of the foaming agent is 10 times.By adjusting the water-binder ratio and silica fume content in the foam concrete mix ratio,it is finally found that when the water-binder ratio is 0.45 and the silica fume content is 10%,the specific weight of the foam concrete is smaller and the strength is greater.Adding a proper amount of polyvinyl alcohol fiber and vitrified microbeads to foam concrete can effectively reduce the mass loss and strength loss of the foamed concrete after drying shrinkage and freeze-thaw cycles;with the increase of the amount of vitrified microbeads,the high-temperature resistance of the foamed concrete is improved.When the temperature is higher than 600?,the strength of the foamed concrete is basically lost.However,the foamed concrete does not ignite or burn after being burned at2000?.When polyvinyl alcohol fibers are mixed with vitrified microbeads(the fiber content is 1.2 kg/m~3,and the vitrified microbead substitution rate is 10%),it can effectively improve the mechanical,physical,and thermal insulation properties of foam concrete.The black-and-white binarization of the foamed concrete cross-section photos and analysis of the pore structure of the foamed concrete using Image-Pro-Plus(IPP)software showed that the polyvinyl alcohol fibers improved the pore structure of the foamed concrete,while vitrified microspheres It has an adverse effect on the pore structure of foamed concrete;when the fiber is mixed with vitrified microbeads(the fiber content is 1.2kg/m~3,and the vitrified microbead replacement rate is 10%),the foam circle diameter of the foamed concrete is reduced.Degree value,average pore size and porosity,so that the mechanical,physical and thermal insulation properties of foamed concrete are improved.