Studying the effect of using CFRP warping on strength of husk rice concrete columns

This research presents the effect of carbon fiber-reinforced polymer (CFRP) on a strength of concrete containing rice husk. Two shapes of columns (circular and square) were used to compare these two types in terms of resistance axial loading. Twelve concrete columns were casting; six are square and others are circular cross-section. All columns of each shape were divided into three groups, and each group consisted of two columns: the first group without CFRP, the second group covered with one layer of CFRP, and the last group covered with two layers of CFRP. The dimensions of the square columns were 300 mm x 300 mm and the height was 900 mm, with reinforced 4-6 mm steel bars. The circular columns were 300 mm in diameter with same height 900 mm and reinforced with 6-6 mm steel bars. Burnt rice husks are added at a rate of 10% of the amount of cement that should be added to the concrete mix. The test results showed the circular columns were the strongest and most resistant to axial loading than square columns. Also, the CFRP wrapping is very effective in strengthening circular concrete columns but significantly less effective in strengthening square concrete columns because the latter have sharp corners and flat sides.