Experimental Study On Mechanical Properties Of Cellulose Fiber Concrete Under Sulfate Attack

The problem of sulfate-eroded concrete is an important reason for the deterioration and failure of concrete,mainly concentrated in China's coastal areas and the saline land area of the north-western salt lake.The influencing factors are complicated,especially in the environment with sulfate-containing splashes and water level changes.The deterioration of concrete is more serious,which seriously affects the safe use and life of concrete buildings in China.The overall face of the Nazixia face rockfill dam is made of cellulose fiber concrete and is located in the northwest saline soil area.Its sulfate content in the environment can reach 4200mg/L or more.Therefore,it is of great significance to carry out research on the degradation law and degradation mechanism of sulfate-eroded cellulose fiber concrete for the durability safety assessment of the NaZiXia concrete face rock fill dam and the future projects using cellulose fiber concrete.In this paper,the research method of combining laboratory test and theoretical analysis is used to study the degradation mechanism and performance degradation law of cellulose fiber concrete under the combined action of sulfate erosion and dry-wet cycle,and establish the compressive strength and splitting strength.The attenuation model of the number of dry and wet cycles is analyzed based on the Zhenhai model and Carreia J model.The main research contents are as follows:(1)The durability test of cellulose fiber concrete under the combined action of sulfate erosion and dry-wet cycles were carried out,considering two situations of different sulfate concentration and different fly ash content,using four indexes apparent phenomena and quality loss rate,compressive strength corrosion resistance coefficient and cleavage strength corrosion resistance coefficient,were used to evaluate the sulfate resistance.(2)The influence of sulfate concentration and fly ash content on the deterioration law of cellulose fiber concrete under the combined action of sulfate erosion and dry-wet cycle was analyzed,and a mechanical damage model was established;mass,;the relationship between mass,compressive strength,splitting and cycle coefficient was established(3)The uniaxial compression test of cellulose fiber concrete under the combined action of sulfate erosion and dry-wet cycle was carried out to study the effects of sulfate concentration and fly ash content respectively,the relationship between the peak stress;peak strain and elastic modulus and the number of cycles were established(4)The stress-strain relationship of the rising section of cellulose fiber concrete under the combined action of sulfate erosion and dry-wet cycle was studied.On the basis of the Zhenhai model and Carreia J model,t the damage stress-strain relationship of cellulose fiber concrete was fitted to rise Segment model...