Bond Behavior of Basalt Fiber-Reinforced Polymer Bars Embedded in Concrete Under Mono-tensile and Cyclic Loads

Abstract

AbstractThis study evaluates the static and fatigue bond behavior in basalt fiber-reinforced polymer (BFRP) bars embedded in concrete. For bond behavior under a mono-tensile load, BFRP bars with four types of surface patterns (round, rectangular, cross-winding, and spiral-winding) were adopted, and 20 groups of rib parameters were introduced for round-type BFRP bars. The bond–slip relationships and the influences of the above parameters on bond behavior were investigated. An analytical model for simulating the relationships of full bond slip was studied by data fitting. For bond behavior under cyclic loads, the relationship between stress levels and the number of cycles was investigated, and the slip of round-ribbed BFRP bars was studied with respect to the number of cycles. The results showed that the rectangular, cross-winding, and spiral-winding ribbed bars experienced serious wear, and that the average bond strength was approximately 80.6% of that of the round-ribbed bars. Thus, the bond behavior of the round rib is superior to those of the other surfaces. In addition, a bond–slip constitutive model for a BFRP bar is proposed, representing four main stages: a micro-slip stage, a slip stage, a descending stage, and a residual stage. Under cyclic loads, an equation was proposed for predicting fatigue life with a regression coefficient of 0.880, and a development law of slip was characterized as three stages: the linear increase stage, the steady increase stage, and the sharp increase stage, respectively.