The effect of basalt fiber on mechanical properties of slag cementing slurries

Compared with the cement system, the slag is more brittle. This feature means it easy to cause submerged cracking, resulting in failure of the oil well cementing. We use slag with higher content of titanium and vanadium produced in Panzhihua city. The effects and mechanisms of basalt fiber (BF) toughening are investigated by mechanical properties testing and microscopic characterization. The results are as follows: (1) the addition of BF can enhance the compressive strength of slag mortars, and the optimum amount is 4%. After 3, 7, 14 and 28 days of maintenance, the strength increased by 31.47%, 46.02%, 43.75% and 45.02%, respectively, compared with the samples without BF (i.e. blank sample). (2) BF significantly improved the toughness of the slag mortars. The impact strengths of the samples with 4% BF added at impact speeds of 4, 6 and 8 m/s were 83.09, 131.71 and 157.90 MPa, respectively. (3) According to microstructure characterization, there is a close physical combination between BF and slag cement, and no extra material is produced. The pore size of all the samples are between 50 and 500 nm.Themost possible pore size of samples containing 4% BF is 117.4 nm and the porosity is 34%. The following conclusions can be drawn: BF improves the toughness of materials by dispersing stress, pulling out energy consumption and bridging to control the generation and development of microcracks. This experiment shows that BF has well toughening on slag mortars, and it can promote the application of slag in well cementing.