Experimental Study On The Mechanical Properties And Salt Corrosion Resistance Of Polypropylene Fiber Foamed Concrete

In the construction industry,there are a lot of problems in the production and use of building materials,which put forward requirements for the development of future materials such as green and sustainable,so that foam concrete with the advantages of light weight,porous and convenient construction has gradually come into people’s sight.At the same time,in order to improve the problems of cracking and shrinkage,experts and scholars chose the method of adding fiber.However,most of the experimental studies on fiber foam concrete are about its basic mechanical properties,mix ratio,thermal performance,etc.,but have not thoroughly studied the relationship between the mechanical properties of the material and the constitutive relationship.And if it involves areas such as saline-alkali land and the surrounding ocean,its salt erosion resistance also needs to be improved.In order to explore the mechanical properties and salt corrosion resistance of polypropylene fiber foamed concrete,the following researches are carried out in this paper:(1)Nine groups of different polypropylene fiber foam concrete mix ratios were designed by the orthogonal experiment method,and their compressive and tensile properties were studied.The influence of polypropylene fiber content,fly ash content and polypropylene fiber length on different mechanical properties is obtained,And respectively use linear function and power function to express the relationship between axial compressive strength and cubic compressive strength,split tensile strength and cubic compressive strength;The cubic polynomial function and rational fraction function are applied to the fitting process,and the constitutive relationship curve of polypropylene fiber foam concrete is fitted piecewise.(2)A 90-day sulfate erosion test was carried out on the polypropylene fiber foamed concrete.During the 90-day erosion cycle,the two erosion indicators,the quality of the specimen and the compressive strength of the specimen,both increased first and then decreased,with the largest changes reaching 9.4% and 22.67%,respectively.The gray system theory is used to predict the compressive strength after a 90-day period.The GM(1,1)model is qualified for the test data and can be used as one of the options for predicting the long-term durability of related materials.(3)Based on the electric flux test,the anti-chloride ion penetration performance of the polypropylene fiber foamed concrete was evaluated.The degree of influence of various factors on its resistance to chloride ion penetration is in the order of: polypropylene fiber content> fly ash content> polypropylene fiber length;The electric flux value of each group of polypropylene fiber foamed concrete is in the range of 2500C～4500C,and the resistance to chloride ion penetration is at a relatively low level.