Experimental studies into the strength of compressed concrete elements reinforced with fiber-reinforced polymer rebars

Introduction. Reinforced concrete structures affected by various aggressive environments operate under off-center compression. Fiber-reinforced polymer (FRP) rebars replacing steel reinforcement in these structures are capable of increasing their durability and decreasing operating costs. However, the use of FRP rebars is limited by insufficient previous research into the methods of designing such constructions. The majority of international regulatory technical documents concerning the design of concrete structures reinforced with FRP rebars indicate the necessity of detailed studies into the stress-strain state of these structures under compression.

Aim. To study the effect of longitude and shear reinforcement on load-bearing characteristic of stressed concrete samples reinforced with longitudinal glass fiber-reinforced polymer (GFRP) rebars.

Materials and methods. The study was carried out using a concrete prism sample with different parameters of longitudinal and shear reinforcement. Five types of GFRP rebars differing in mechanical properties, as well as anchorage were considered. Shear reinforcement of the samples was performed with metal clamps at different pitches. The sample testing was fulfilled using centric compression with static load.

Results. The strength values of compressed concrete samples reinforced with GFRP rebars were obtained. An increase of up to 19 % in the strength of compressed concrete samples reinforced with GFRP rebars was found in comparison with non-reinforced samples.

Conclusions. The strength of compressed concrete elements increases when reinforced with glass fiber-reinforced polymer rebars. The degree of increase in the strength of such elements depends on the number of longitudinal reinforcements, as well as shear reinforcement pitch. The effect of the type of anchorage of GFRP rebars along with the values of its compression resistance on the strength of compressed concrete elements have not been established. 

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