Bonding Properties Of GFRP Bars And Seawater Sand PVA Cement-based Composites(Concrete)

Reducing the corrosion of reinforced concrete in coastal areas has been one of the hot issues in academic and engineering circles.This paper uses sea sand and artificial sea water to mix cement-based composites to study the bonding properties of fiber tendons and cement-based composites.Considering the amount of PVA fiber,seawater concentration,strength of cement-based materials and age,and embedding GFRP bars with a diameter of 12mm,a total of 162 cube drawn test pieces were produced.The following results were obtained through experiments:1.There are two types of damage:pull-out failure and split failure.Most of the drawn specimens are in the form of pullout failure,and very few specimens are in the form of split failure.The increase in seawater concentration,age,and uneven stress on the surface of ribs increased the probability of splitting failure.The damaged interface occurs between the resin on the surface of the fiber tendon and the internal fibers.2.When the age and seawater concentration are constant,as the fiber content increases,the S_uvalue of the C30 and C50 series specimens decreases,and the C50specimens have a smaller decline than the C30 specimens.The P_uvalue of the C30and C50 series specimens decreases,the downward trend is that the P_uvalue of the C50 specimen is smaller than that of the C30 specimen.When the age and the amount of PVA are constant,as the seawater concentration increases,the S_uvalue of the C30specimen increases in general,and the P_uvalue increases greatly at three times the concentration.3.For the bond slip curve,when the PVA content is constant,the improvement of the bonding ability of 3 times the concentration of seawater is very obvious at all ages.The improvement effect is reflected in delaying the failure of the drawn test piece,increasing the ultimate bonding strength and Residual bond strength.The increase in seawater concentration has a small effect on the limit adhesion of C50 specimens,while the limit adhesion of C30 specimens is greatly affected by changes in seawater concentration.4.The bond strength of the drawn specimen tends to be stable after reaching the180-day age.Based on the 180-day age bond-slip curve,a constitutive model for the bond-slip curve of GFRP bars seawater and sea-sand cement-based composites is given.The fitting curve matches the test curve and model curve well.