Experimental study on an adhesion of composite rod and concrete

The object of research is the connection of the composite rods glued into concrete. The objective of this study is to determine the bond strength of the bar to be concrete based on a series of pull-out tests of bonded composite bars. The average shear stresses of the bar to concrete bond at the maximum pull-out force are needed to determine the required anchorage length of the composite rods. Method. Two series of pull-out tests were performed on composite rods glued into a concrete cube with epoxy glue. The series differed in the thickness of the adhesive layer: 7 mm and 3.5 mm. To determine the class of concrete, three samples were tested for compression. Finite element modeling of the pulling of out of a composite rod from a concrete cube was performed and the numerical results were compared with experimental data. Results. Based on the test results, for each series, the average value of the maximum shear stress acting between the rod and concrete was calculated. The values of the stresses were determined by a confidence level of 0.95. Pull-out tests were performed on composite rods cemented into a concrete cube. Experiments showed that in this case the pull-out force and average shear stress increased by approximately 20-25 percent.

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