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Axial Compressive Performance of Rectangular Short Concrete Column Strengthened with CFRP Grid Reinforced ECC Matrix

confined concrete; CFRP grid; ECC matrix; analytical model; lateral constraint stiffness; transverse effective strain

Based on the relevant research on analytical models of confined concrete, the key factors affecting the compressive performance of passive confined concrete columns were discussed. Then, rectangular short concrete columns strengthened with carbon-fibre-reinforced-plastics (CFRP) grid reinforced engineering cementitious composite (ECC) matrix were prepared, and the compressive performances of short columns were experimentally studied. The effect of different lateral constraints on the improvement of compressive performance were clarified. The test results show that the brittle failure characteristics of concrete is improved for concrete columns strengthened with CFRP grid reinforced ECC matrix, which exhibits a smaller slope in downward section. The failure of concrete columns strengthened with CFRP grid reinforced ECC matrix is characterized as the peeling of CFRP grid and ECC matrix at the corner. With the increase of reinforcing layers, higher values of compressive strength and peak strain can be achieved for confined concrete while the transverse effective strain of constraint layer declines. A model for predicting the compressive strength of confined concrete strengthened with CFRP grid reinforced ECC matrix is obtained on the basis of the comparative analysis between analytical models of confined concrete and relevant experimental results.