Research And Development And Mechanical Properties Of Polyurethane Foamed Ceramsite Concrete Material

The construction of highway tunnels in China started late.Many key technologies still have a certain gap co MPared with developed countries,and the geological conditions in our country are more complicated.There are many reasons for the actual collapse during construction.Occurred,the construction safety problem was extremely serious.The construction of the secondary lining is particularly important.We all k Now that the highway tunnel may be built in the initial stage,and the soil may still squeeze the secondary lining over time,causing the secondary lining to crack or even collapse,although many scholars have already Committed to adding an interlayer on the secondary lining to resist the pressure caused by part of the soil,but there are still deficiencies.If there is high geothermal heat in the tunnel project,it will not only affect the labor production schedule,but the presence of additional temperature stress will also cause the silicon lining to crack,which will affect the stability of the tunnel structure.Therefore,it is of great significance to develop a new type of interlayer material.This new type of interlayer material should have a certain compressive strength(2MPa)and deformation(> 50%),which can not only buffer and resist the pressure caused by part of the soil,but also have Insulation function.In this paper,starting from the design mix ratio of the new interlayer material,the best mix ratio is determined by changing the ceramsite type,the amount and the polyurethane foam mix ratio in the early stage,and taking the compressive strength and compression amount as the design indicators.Based on the mix ratio,the new model The interlayer material is studied from the mechanical properties,and finally the compressive strength of the new interlayer material mixed with cement is analyzed.The specific tests and conclusions are as follows:By searching for the research data of ceramsite and polyurethane foam,the design idea of mix ratio is the proportion of polyurethane foam in the ceramsite and the content of the ceramsite itself.In this paper,5 groups of ceramsite are made up,accounting for 20% and 40 %,60%,80%,100%,and 6 groups of polyurethane foam accounted for 5%,10%,15%,20%,25%,30% of the maximum incorporation of ceramsite,based on compressive strength and deformation Indicators,through experimental research,determine the best blending amount of polyurethane foam and ceramsite,and finally determine the test material usage and test mix ratio.It is determined that the compressive strength reaches 2MPa and the deformation exceeds50% of the mix ratio group,and there are five groups in the final mix ratio group.Varying the types of ceramsite and analyzing the influence of different types of ceramsite on the compressive strength.In this paper,5 groups of ceramsite are made up to account for 20%,40%,60%,80%,100%,and 6 groups of polyurethane The foam accounts for 5%,10%,15%,20%,25%,and 30% of the maximum incorporation of ceramsite.Through experimental studies,the results show that the overall compressive strength and deformation of the gravel-type ceramsite with larger particle size The amount is lower than that of ordinary ceramsite,but the change law of compressive strength and deformation of crushed stone ceramsite is about the same as that of ordinary ceramsite;at the same time,determine the best blending amount of polyurethane foam and crushed ceramsite,and determine It meets the mix ratio group with compressive strength of 2MPa and the deformation exceeds 50%.There are four groups in the final mix ratio group.In this paper,three groups of ceramsites account for 20%,50%,100% of the maximum content of ceramsite and polyurethane foam in less,half and more cases,and three groups of polyurethane foam account for ceramsite.5%,15%,30% of the maximum blending,the axial compression performance,flexural performance and i MPact resistance test of the 6 groups of mix ratios are conducted,and the axial compression performance,flexural performance and resistance of the 6 groups are explored IMPact performance,and the load-displacement curve of the axial compressive strength of 6 sets of mix ratios was analyzed.In this paper,the three groups of ceramsite account for 20%,50%,100% of their maximum incorporation,and the three groups of polyurethane foam account for 5%,15%,30% of the maximum incorporation of ceramsite.On this basis,cement is added,The mixing ratio of 1 group of single ceramsite and the mixing ratio of 1 group of single urethane foam are used as a co MParison to improve the compressive strength of the material and there is no big change in the amount of deformation.The blended amount of cement is 10%,20%,30%,and the three groups of polyurethane foam account for the maximum blended amount of ceramsite.The blended cement amount is5%,10%,and 15%.The change of compressive strength and the amount of deformation showed that the compressive strength of the 6 groups of mixing ratios with cement were all improved.