Influence of magnetic field treated water on the compressive strength and bond strength of concrete containing silica fume

The overall objective of this study is to investigate the effect of magnetic field treated water and silica fume content on the compressive strength and bond strength of concrete. A total of ninety specimens were cast and tested under compression and pullout tests. In order to fully understand the concrete strength development, both tests were carried out at 7 and 28 days of concrete age. Normal water and magnetic water were used in the mix using different silica fume content. The results showed significant increase in the compression strength when magnetic water was used regardless of the silica fume content. Specimens prepared with magnetized water showed an increase in the bond strength compared to those prepared with normal water at all silica fume contents. The results also showed the use of high content of silica fume reduces the bond strength due to the reduction in adhesive properties between steel and concrete. The ultimate pullout load for 16 mm diameter bar was larger than that for use of larger than that for the 12 mm bar size but the bond strength of the larger diameter bar size is smaller since it has larger surface embedded area. The effect of silica fume on bar size illustrated that for a smaller bar size a lower development of bond strength is recorded because the distribution of silica fume particles around the small surface area reduces the adhesion forces between concrete and steel bars. Finally, as expected, the results showed that age of concrete has significant influence on the bond strength. The main contribution of this work is to prove that magnetic field treated water can enhance not only the compressive strength of concrete but also the bond strength between steel bar and concrete.